diff --git a/Directory.Build.props b/Directory.Build.props
index e42935c9..45a935d0 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -4,6 +4,17 @@
     <LangVersion>9</LangVersion>
     <Nullable>warnings</Nullable>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <!--
+      > [CS8785] warning is emitted if a source generator failed to produce output
+      > due to an exception and there are no generated files. Since the warning
+      > is easy to miss among errors from missing sources it's useful to promote
+      > it to an error.
+      Credit:
+      - Andrey Dyatlov
+      - https://github.com/TessenR/BestPracticesSourceGeneratorsDemo
+      - b8be40f0e153f46ccc79682397680be1b2649b6d
+    -->
+    <MSBuildWarningsAsErrors>CS8785</MSBuildWarningsAsErrors>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
diff --git a/DocoptNet.sln b/DocoptNet.sln
index e723b406..44397d2e 100644
--- a/DocoptNet.sln
+++ b/DocoptNet.sln
@@ -31,8 +31,34 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		README.rst = README.rst
 	EndProjectSection
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DocoptNet.CodeGeneration", "src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj", "{37D45A51-EB3E-4D6D-9943-EF2F3967343C}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "SourceGenerator", "SourceGenerator", "{99846126-1D88-42CC-897C-ACEA7C2DBB2B}"
+	ProjectSection(SolutionItems) = preProject
+		eg\SourceGenerator\Directory.Build.props = eg\SourceGenerator\Directory.Build.props
+		eg\SourceGenerator\Directory.Build.targets = eg\SourceGenerator\Directory.Build.targets
+	EndProjectSection
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NavalFate", "eg\SourceGenerator\NavalFate\NavalFate.csproj", "{E41419E5-251C-4093-ADDE-77EF694964E3}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ArgumentsExample", "eg\SourceGenerator\ArgumentsExample\ArgumentsExample.csproj", "{99A5B165-A15E-4CE1-B68E-E0992F4478D9}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CalculatorExample", "eg\SourceGenerator\CalculatorExample\CalculatorExample.csproj", "{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CountedExample", "eg\SourceGenerator\CountedExample\CountedExample.csproj", "{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "OddEvenExample", "eg\SourceGenerator\OddEvenExample\OddEvenExample.csproj", "{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "OptionsExample", "eg\SourceGenerator\OptionsExample\OptionsExample.csproj", "{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "OptionsShortcutExample", "eg\SourceGenerator\OptionsShortcutExample\OptionsShortcutExample.csproj", "{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "QuickExample", "eg\SourceGenerator\QuickExample\QuickExample.csproj", "{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}"
+EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DocoptNet.Playground", "src\DocoptNet.Playground\DocoptNet.Playground.csproj", "{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Git", "eg\SourceGenerator\Git\Git.csproj", "{63B571D9-DA1B-4209-B4E2-59F0AC529E06}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -95,6 +121,114 @@ Global
 		{5A641DFB-CB1A-4044-AF52-554CC8904449}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
 		{5A641DFB-CB1A-4044-AF52-554CC8904449}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{5A641DFB-CB1A-4044-AF52-554CC8904449}.Release|x86.ActiveCfg = Release|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Debug|x86.Build.0 = Debug|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Release|x86.ActiveCfg = Release|Any CPU
+		{37D45A51-EB3E-4D6D-9943-EF2F3967343C}.Release|x86.Build.0 = Release|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Debug|x86.Build.0 = Debug|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Release|x86.ActiveCfg = Release|Any CPU
+		{E41419E5-251C-4093-ADDE-77EF694964E3}.Release|x86.Build.0 = Release|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Debug|x86.Build.0 = Debug|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Release|x86.ActiveCfg = Release|Any CPU
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9}.Release|x86.Build.0 = Release|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Debug|x86.Build.0 = Debug|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Release|x86.ActiveCfg = Release|Any CPU
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E}.Release|x86.Build.0 = Release|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Debug|x86.Build.0 = Debug|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Release|Any CPU.Build.0 = Release|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Release|x86.ActiveCfg = Release|Any CPU
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18}.Release|x86.Build.0 = Release|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Debug|x86.Build.0 = Debug|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Release|x86.ActiveCfg = Release|Any CPU
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B}.Release|x86.Build.0 = Release|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Debug|x86.Build.0 = Debug|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Release|x86.ActiveCfg = Release|Any CPU
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE}.Release|x86.Build.0 = Release|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Debug|x86.Build.0 = Debug|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Release|Any CPU.Build.0 = Release|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Release|x86.ActiveCfg = Release|Any CPU
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74}.Release|x86.Build.0 = Release|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Debug|x86.Build.0 = Debug|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Release|x86.ActiveCfg = Release|Any CPU
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D}.Release|x86.Build.0 = Release|Any CPU
 		{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
@@ -107,12 +241,34 @@ Global
 		{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}.Release|x86.ActiveCfg = Release|Any CPU
 		{93595D4E-5AE9-4714-AC8B-1FB24D68A15C}.Release|x86.Build.0 = Release|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Debug|x86.Build.0 = Debug|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Release|Any CPU.Build.0 = Release|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Release|x86.ActiveCfg = Release|Any CPU
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{2B454F8B-D702-4281-80DF-367142007B0C} = {AE631D61-6BE6-438F-A535-955BB9A0218F}
+		{99846126-1D88-42CC-897C-ACEA7C2DBB2B} = {AE631D61-6BE6-438F-A535-955BB9A0218F}
+		{E41419E5-251C-4093-ADDE-77EF694964E3} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{99A5B165-A15E-4CE1-B68E-E0992F4478D9} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{8BCB1D8B-0233-48C5-B5C6-6E3EDB566D3E} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{962D6BAB-A7DE-41BC-9E91-567A6EEE4C18} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{E4EB11FF-6FD7-42F5-A5CD-2C7C2B52568B} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{6C3733DD-C7BD-47C7-BF9A-691A3D0ACCCE} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{21E4EA57-6291-4C58-BFC4-CA8ACF48DB74} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{86843F8B-9B83-4985-9E68-77F9ACF4DA2D} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
+		{63B571D9-DA1B-4209-B4E2-59F0AC529E06} = {99846126-1D88-42CC-897C-ACEA7C2DBB2B}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {3DEED27A-6D3F-4F2E-A5D5-1F71648F2413}
diff --git a/eg/SourceGenerator/ArgumentsExample/ArgumentsExample.csproj b/eg/SourceGenerator/ArgumentsExample/ArgumentsExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/ArgumentsExample/ArgumentsExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/ArgumentsExample/Program.cs b/eg/SourceGenerator/ArgumentsExample/Program.cs
new file mode 100644
index 00000000..42849e89
--- /dev/null
+++ b/eg/SourceGenerator/ArgumentsExample/Program.cs
@@ -0,0 +1,36 @@
+using System;
+using DocoptNet.Generated;
+using ArgumentsExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args);
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Help       = {arguments.OptHelp    },
+    V          = {arguments.OptV       },
+    Q          = {arguments.OptQ       },
+    R          = {arguments.OptR       },
+    Left       = {arguments.OptLeft    },
+    Right      = {arguments.OptRight   },
+    Correction = {arguments.ArgCorrection},
+    File       = [{string.Join(", ", arguments.ArgFile)}],
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/ArgumentsExample/Program.docopt.txt b/eg/SourceGenerator/ArgumentsExample/Program.docopt.txt
new file mode 100644
index 00000000..ecdbbaf8
--- /dev/null
+++ b/eg/SourceGenerator/ArgumentsExample/Program.docopt.txt
@@ -0,0 +1,17 @@
+Usage: ArgumentsExample [-vqrh] [FILE] ...
+       ArgumentsExample (--left | --right) CORRECTION FILE
+
+Process FILE and optionally apply correction to either left-hand side or
+right-hand side.
+
+Arguments:
+  FILE        optional input file
+  CORRECTION  correction angle, needs FILE, --left or --right to be present
+
+Options:
+  -h --help
+  -v       verbose mode
+  -q       quiet mode
+  -r       make report
+  --left   use left-hand side
+  --right  use right-hand side
diff --git a/eg/SourceGenerator/CalculatorExample/CalculatorExample.csproj b/eg/SourceGenerator/CalculatorExample/CalculatorExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/CalculatorExample/CalculatorExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/CalculatorExample/Program.cs b/eg/SourceGenerator/CalculatorExample/Program.cs
new file mode 100644
index 00000000..a0d7ef17
--- /dev/null
+++ b/eg/SourceGenerator/CalculatorExample/Program.cs
@@ -0,0 +1,36 @@
+using System;
+using DocoptNet.Generated;
+using CalculatorExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args);
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Help     = {arguments.OptHelp    },
+    +        = {arguments.CmdPlus    },
+    -        = {arguments.CmdMinus   },
+    *        = {arguments.CmdStar    },
+    /        = {arguments.CmdSlash   },
+    Function = {arguments.ArgFunction},
+    Comma    = {arguments.CmdComma   },
+    Value    = [{string.Join(", ", arguments.ArgValue)}],
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/CalculatorExample/Program.docopt.txt b/eg/SourceGenerator/CalculatorExample/Program.docopt.txt
new file mode 100644
index 00000000..1b4c5281
--- /dev/null
+++ b/eg/SourceGenerator/CalculatorExample/Program.docopt.txt
@@ -0,0 +1,14 @@
+Not a serious example.
+
+Usage:
+  calculator_example.py <value> ( ( + | - | * | / ) <value> )...
+  calculator_example.py <function> <value> [( , <value> )]...
+  calculator_example.py (-h | --help)
+
+Examples:
+  calculator_example.py 1 + 2 + 3 + 4 + 5
+  calculator_example.py 1 + 2 '*' 3 / 4 - 5    # note quotes around '*'
+  calculator_example.py sum 10 , 20 , 30 , 40
+
+Options:
+  -h, --help
diff --git a/eg/SourceGenerator/CountedExample/CountedExample.csproj b/eg/SourceGenerator/CountedExample/CountedExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/CountedExample/CountedExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/CountedExample/Program.cs b/eg/SourceGenerator/CountedExample/Program.cs
new file mode 100644
index 00000000..2240c565
--- /dev/null
+++ b/eg/SourceGenerator/CountedExample/Program.cs
@@ -0,0 +1,33 @@
+using System;
+using DocoptNet.Generated;
+using CountedExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args);
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Help       = {arguments.OptHelp },
+    V          = {arguments.OptV    },
+    Go         = {arguments.CmdGo   },
+    File       = [{string.Join(", ", arguments.ArgFile)}],
+    Path       = {arguments.OptPath },
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/CountedExample/Program.docopt.txt b/eg/SourceGenerator/CountedExample/Program.docopt.txt
new file mode 100644
index 00000000..4f829264
--- /dev/null
+++ b/eg/SourceGenerator/CountedExample/Program.docopt.txt
@@ -0,0 +1,10 @@
+Usage: CountedExample --help
+       CountedExample -v...
+       CountedExample go [go]
+       CountedExample (--path=<path>)...
+       CountedExample <file> <file>
+
+Try: CountedExample -vvvvvvvvvv
+     CountedExample go go
+     CountedExample --path ./here --path ./there
+     CountedExample this.txt that.txt
diff --git a/eg/SourceGenerator/Directory.Build.props b/eg/SourceGenerator/Directory.Build.props
new file mode 100644
index 00000000..581ec552
--- /dev/null
+++ b/eg/SourceGenerator/Directory.Build.props
@@ -0,0 +1,10 @@
+<Project>
+
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)..'))" />
+
+  <PropertyGroup>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+    <DebugDocoptNet>false</DebugDocoptNet>
+  </PropertyGroup>
+
+</Project>
diff --git a/eg/SourceGenerator/Directory.Build.targets b/eg/SourceGenerator/Directory.Build.targets
new file mode 100644
index 00000000..06c305d3
--- /dev/null
+++ b/eg/SourceGenerator/Directory.Build.targets
@@ -0,0 +1,7 @@
+<Project>
+
+  <PropertyGroup>
+    <CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)Generated</CompilerGeneratedFilesOutputPath>
+  </PropertyGroup>
+
+</Project>
diff --git a/eg/SourceGenerator/Git/Git.csproj b/eg/SourceGenerator/Git/Git.csproj
new file mode 100644
index 00000000..fc3f4133
--- /dev/null
+++ b/eg/SourceGenerator/Git/Git.csproj
@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+    <CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)Generated</CompilerGeneratedFilesOutputPath>
+    <DebugDocoptNet>false</DebugDocoptNet>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- FIXME Re-enable after addressing CS0102 errors -->
+    <None Remove="GitBranch.docopt.txt" />
+    <None Remove="GitCheckout.docopt.txt" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/Git/Git.docopt.txt b/eg/SourceGenerator/Git/Git.docopt.txt
new file mode 100644
index 00000000..7895b0dc
--- /dev/null
+++ b/eg/SourceGenerator/Git/Git.docopt.txt
@@ -0,0 +1,21 @@
+usage: git [--version] [--exec-path=<path>] [--html-path]
+           [-p|--paginate|--no-pager] [--no-replace-objects]
+           [--bare] [--git-dir=<path>] [--work-tree=<path>]
+           [-c <name>=<value>] [--help]
+           <command> [<args>...]
+
+options:
+   -c <name=value>
+   -h, --help
+   -p, --paginate
+
+The most commonly used git commands are:
+   add        Add file contents to the index
+   branch     List, create, or delete branches
+   checkout   Checkout a branch or paths to the working tree
+   clone      Clone a repository into a new directory
+   commit     Record changes to the repository
+   push       Update remote refs along with associated objects
+   remote     Manage set of tracked repositories
+
+See 'git help <command>' for more information on a specific command.
diff --git a/eg/SourceGenerator/Git/GitAdd.docopt.txt b/eg/SourceGenerator/Git/GitAdd.docopt.txt
new file mode 100644
index 00000000..96fb4d6a
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitAdd.docopt.txt
@@ -0,0 +1,16 @@
+usage: git add [options] [--] [<filepattern>...]
+
+    -h, --help
+    -n, --dry-run        dry run
+    -v, --verbose        be verbose
+
+    -i, --interactive    interactive picking
+    -p, --patch          select hunks interactively
+    -e, --edit           edit current diff and apply
+    -f, --force          allow adding otherwise ignored files
+    -u, --update         update tracked files
+    -N, --intent-to-add  record only the fact that the path will be added later
+    -A, --all            add all, noticing removal of tracked files
+    --refresh            don't add, only refresh the index
+    --ignore-errors      just skip files which cannot be added because of errors
+    --ignore-missing     check if - even missing - files are ignored in dry run
diff --git a/eg/SourceGenerator/Git/GitBranch.docopt.txt b/eg/SourceGenerator/Git/GitBranch.docopt.txt
new file mode 100644
index 00000000..811e56c2
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitBranch.docopt.txt
@@ -0,0 +1,25 @@
+usage: git branch [options] [-r | -a] [--merged=<commit> | --no-merged=<commit>]
+       git branch [options] [-l] [-f] <branchname> [<start-point>]
+       git branch [options] [-r] (-d | -D) <branchname>
+       git branch [options] (-m | -M) [<oldbranch>] <newbranch>
+
+Generic options
+    -h, --help
+    -v, --verbose         show hash and subject, give twice for upstream branch
+    -t, --track           set up tracking mode (see git-pull(1))
+    --set-upstream        change upstream info
+    --color=<when>        use colored output
+    -r                    act on remote-tracking branches
+    --contains=<commit>   print only branches that contain the commit
+    --abbrev=<n>          use <n> digits to display SHA-1s
+
+Specific git-branch actions:
+    -a                    list both remote-tracking and local branches
+    -d                    delete fully merged branch
+    -D                    delete branch (even if not merged)
+    -m                    move/rename a branch and its reflog
+    -M                    move/rename a branch, even if target exists
+    -l                    create the branch's reflog
+    -f, --force           force creation (when already exists)
+    --no-merged=<commit>  print only not merged branches
+    --merged=<commit>     print only merged branches
diff --git a/eg/SourceGenerator/Git/GitCheckout.docopt.txt b/eg/SourceGenerator/Git/GitCheckout.docopt.txt
new file mode 100644
index 00000000..1e9fad2b
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitCheckout.docopt.txt
@@ -0,0 +1,15 @@
+usage: git checkout [options] <branch>
+       git checkout [options] <branch> -- <file>...
+    -q, --quiet           suppress progress reporting
+    -b <branch>           create and checkout a new branch
+    -B <branch>           create/reset and checkout a branch
+    -l                    create reflog for new branch
+    -t, --track           set upstream info for new branch
+    --orphan <new branch>
+                          new unparented branch
+    -2, --ours            checkout our version for unmerged files
+    -3, --theirs          checkout their version for unmerged files
+    -f, --force           force checkout (throw away local modifications)
+    -m, --merge           perform a 3-way merge with the new branch
+    --conflict <style>    conflict style (merge or diff3)
+    -p, --patch           select hunks interactively
diff --git a/eg/SourceGenerator/Git/GitClone.docopt.txt b/eg/SourceGenerator/Git/GitClone.docopt.txt
new file mode 100644
index 00000000..33399c47
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitClone.docopt.txt
@@ -0,0 +1,22 @@
+usage: git clone [options] [--] <repo> [<dir>]
+    -v, --verbose         be more verbose
+    -q, --quiet           be more quiet
+    --progress            force progress reporting
+    -n, --no-checkout     don't create a checkout
+    --bare                create a bare repository
+    --mirror              create a mirror repository (implies bare)
+    -l, --local           to clone from a local repository
+    --no-hardlinks        don't use local hardlinks, always copy
+    -s, --shared          setup as shared repository
+    --recursive           initialize submodules in the clone
+    --recurse-submodules  initialize submodules in the clone
+    --template <template-directory>
+                          directory from which templates will be used
+    --reference <repo>    reference repository
+    -o, --origin <branch>
+                          use <branch> instead of 'origin' to track upstream
+    -b, --branch <branch>
+                          checkout <branch> instead of the remote's HEAD
+    -u, --upload-pack <path>
+                          path to git-upload-pack on the remote
+    --depth <depth>       create a shallow clone of that depth
diff --git a/eg/SourceGenerator/Git/GitCommit.docopt.txt b/eg/SourceGenerator/Git/GitCommit.docopt.txt
new file mode 100644
index 00000000..767a6f43
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitCommit.docopt.txt
@@ -0,0 +1,43 @@
+usage: git commit [options] [--] [<filepattern>...]
+
+    -h, --help
+    -q, --quiet           suppress summary after successful commit
+    -v, --verbose         show diff in commit message template
+
+Commit message options
+    -F, --file <file>     read message from file
+    --author <author>     override author for commit
+    --date <date>         override date for commit
+    -m, --message <message>
+                          commit message
+    -c, --reedit-message <commit>
+                          reuse and edit message from specified commit
+    -C, --reuse-message <commit>
+                          reuse message from specified commit
+    --fixup <commit>      use autosquash formatted message to fixup specified commit
+    --squash <commit>     use autosquash formatted message to squash specified commit
+    --reset-author        the commit is authored by me now
+                          (used with -C-c/--amend)
+    -s, --signoff         add Signed-off-by:
+    -t, --template <file>
+                          use specified template file
+    -e, --edit            force edit of commit
+    --cleanup <default>   how to strip spaces and #comments from message
+    --status              include status in commit message template
+
+Commit contents options
+    -a, --all             commit all changed files
+    -i, --include         add specified files to index for commit
+    --interactive         interactively add files
+    -o, --only            commit only specified files
+    -n, --no-verify       bypass pre-commit hook
+    --dry-run             show what would be committed
+    --short               show status concisely
+    --branch              show branch information
+    --porcelain           machine-readable output
+    -z, --null            terminate entries with NUL
+    --amend               amend previous commit
+    --no-post-rewrite     bypass post-rewrite hook
+    -u, --untracked-files=<mode>
+                          show untracked files, optional modes: all, normal, no.
+                          [default: all]
diff --git a/eg/SourceGenerator/Git/GitPush.docopt.txt b/eg/SourceGenerator/Git/GitPush.docopt.txt
new file mode 100644
index 00000000..646e663c
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitPush.docopt.txt
@@ -0,0 +1,20 @@
+usage: git push [options] [<repository> [<refspec>...]]
+
+    -h, --help
+    -v, --verbose         be more verbose
+    -q, --quiet           be more quiet
+    --repo <repository>   repository
+    --all                 push all refs
+    --mirror              mirror all refs
+    --delete              delete refs
+    --tags                push tags (can't be used with --all or --mirror)
+    -n, --dry-run         dry run
+    --porcelain           machine-readable output
+    -f, --force           force updates
+    --thin                use thin pack
+    --receive-pack <receive-pack>
+                          receive pack program
+    --exec <receive-pack>
+                          receive pack program
+    -u, --set-upstream    set upstream for git pull/status
+    --progress            force progress reporting
diff --git a/eg/SourceGenerator/Git/GitRemote.docopt.txt b/eg/SourceGenerator/Git/GitRemote.docopt.txt
new file mode 100644
index 00000000..44108508
--- /dev/null
+++ b/eg/SourceGenerator/Git/GitRemote.docopt.txt
@@ -0,0 +1,14 @@
+usage: git remote [-v | --verbose]
+       git remote add [-t <branch>] [-m <master>] [-f] [--mirror] <name> <url>
+       git remote rename <old> <new>
+       git remote rm <name>
+       git remote set-head <name> (-a | -d | <branch>)
+       git remote [-v | --verbose] show [-n] <name>
+       git remote prune [-n | --dry-run] <name>
+       git remote [-v | --verbose] update [-p | --prune] [(<group> | <remote>)...]
+       git remote set-branches <name> [--add] <branch>...
+       git remote set-url <name> <newurl> [<oldurl>]
+       git remote set-url --add <name> <newurl>
+       git remote set-url --delete <name> <url>
+
+    -v, --verbose         be verbose; must be placed before a subcommand
diff --git a/eg/SourceGenerator/Git/Program.cs b/eg/SourceGenerator/Git/Program.cs
new file mode 100644
index 00000000..085fdbae
--- /dev/null
+++ b/eg/SourceGenerator/Git/Program.cs
@@ -0,0 +1,60 @@
+#nullable enable
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using DocoptNet.Generated;
+using Git;
+
+try
+{
+    return Run(args);
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (Exception e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+static int Run(string[] args)
+{
+    var arguments = GitArguments.Apply(args, version: "git version 1.7.4.4", optionsFirst: true);
+
+    Console.WriteLine("global arguments:");
+    foreach (var (name, value) in arguments)
+        Console.WriteLine($"{name} = {value}");
+
+    Console.WriteLine("command arguments:");
+
+    IEnumerable<KeyValuePair<string, object?>> Apply(Func<IEnumerable<string>, IEnumerable<KeyValuePair<string, object?>>> f)
+    {
+        var argv = new[] { arguments.ArgCommand! }.Concat(arguments.ArgArgs).ToArray();
+        return f(argv);
+    }
+
+    var commandArgs = arguments.ArgCommand switch
+    {
+        "add"       => Apply(args => GitAddArguments.Apply(args)),
+    // FIXME Next two command produce following errors:
+    // - error CS0102: The type 'GitBranchArguments' already contains a definition for 'OptD'
+    // - error CS0102: The type 'GitBranchArguments' already contains a definition for 'OptM'
+    // - error CS0102: The type 'GitCheckoutArguments' already contains a definition for 'OptB'
+    // "branch"     => Apply(args => GitBranchArguments.Apply(args)),
+    // "checkout"   => Apply(args => GitCheckoutArguments.Apply(args)),
+        "clone"     => Apply(args => GitCloneArguments.Apply(args)),
+        "commit"    => Apply(args => GitCommitArguments.Apply(args)),
+        "push"      => Apply(args => GitPushArguments.Apply(args)),
+        "remote"    => Apply(args => GitRemoteArguments.Apply(args)),
+        var command => throw new ApplicationException($"{command} is not a Git command. See 'git help'.")
+    };
+
+    foreach (var (name, value) in commandArgs)
+        Console.WriteLine($"{name} = {value}");
+
+    return 0;
+}
diff --git a/eg/SourceGenerator/NavalFate/NavalFate.csproj b/eg/SourceGenerator/NavalFate/NavalFate.csproj
new file mode 100644
index 00000000..2e970b3c
--- /dev/null
+++ b/eg/SourceGenerator/NavalFate/NavalFate.csproj
@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+    <CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)Generated</CompilerGeneratedFilesOutputPath>
+    <DebugDocoptNet>false</DebugDocoptNet>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/NavalFate/Program.cs b/eg/SourceGenerator/NavalFate/Program.cs
new file mode 100644
index 00000000..dd0f69ff
--- /dev/null
+++ b/eg/SourceGenerator/NavalFate/Program.cs
@@ -0,0 +1,43 @@
+using System;
+using DocoptNet.Generated;
+using NavalFate;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args, version: "Naval Fate 2.0");
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Ship     = {arguments.CmdShip    },
+    New      = {arguments.CmdNew     },
+    Name     = [{string.Join(", ", arguments.ArgName)}],
+    Move     = {arguments.CmdMove    },
+    X        = {arguments.ArgX       },
+    Y        = {arguments.ArgY       },
+    Speed    = {arguments.OptSpeed   },
+    Shoot    = {arguments.CmdShoot   },
+    Mine     = {arguments.CmdMine    },
+    Set      = {arguments.CmdSet     },
+    Remove   = {arguments.CmdRemove  },
+    Moored   = {arguments.OptMoored  },
+    Drifting = {arguments.OptDrifting},
+    Help     = {arguments.OptHelp    },
+    Version  = {arguments.OptVersion },
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/NavalFate/Program.docopt.txt b/eg/SourceGenerator/NavalFate/Program.docopt.txt
new file mode 100644
index 00000000..8d9198b4
--- /dev/null
+++ b/eg/SourceGenerator/NavalFate/Program.docopt.txt
@@ -0,0 +1,16 @@
+Naval Fate.
+
+    Usage:
+      naval_fate.exe ship new <name>...
+      naval_fate.exe ship <name> move <x> <y> [--speed=<kn>]
+      naval_fate.exe ship shoot <x> <y>
+      naval_fate.exe mine (set|remove) <x> <y> [--moored | --drifting]
+      naval_fate.exe (-h | --help)
+      naval_fate.exe --version
+
+    Options:
+      -h --help     Show this screen.
+      --version     Show version.
+      --speed=<kn>  Speed in knots [default: 10].
+      --moored      Moored (anchored) mine.
+      --drifting    Drifting mine.
diff --git a/eg/SourceGenerator/OddEvenExample/OddEvenExample.csproj b/eg/SourceGenerator/OddEvenExample/OddEvenExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/OddEvenExample/OddEvenExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/OddEvenExample/Program.cs b/eg/SourceGenerator/OddEvenExample/Program.cs
new file mode 100644
index 00000000..c226b5a0
--- /dev/null
+++ b/eg/SourceGenerator/OddEvenExample/Program.cs
@@ -0,0 +1,31 @@
+using System;
+using DocoptNet.Generated;
+using OddEvenExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args);
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Help = {arguments.OptHelp},
+    Odd  = [{string.Join(", ", arguments.ArgOdd)}],
+    Even = [{string.Join(", ", arguments.ArgEven)}],
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/OddEvenExample/Program.docopt.txt b/eg/SourceGenerator/OddEvenExample/Program.docopt.txt
new file mode 100644
index 00000000..65b4d991
--- /dev/null
+++ b/eg/SourceGenerator/OddEvenExample/Program.docopt.txt
@@ -0,0 +1,7 @@
+Usage: OddEvenExample [-h | --help] (ODD EVEN)...
+
+Example, try:
+  OddEvenExample 1 2 3 4
+
+Options:
+  -h, --help
diff --git a/eg/SourceGenerator/OptionsExample/OptionsExample.csproj b/eg/SourceGenerator/OptionsExample/OptionsExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/OptionsExample/OptionsExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/OptionsExample/Program.cs b/eg/SourceGenerator/OptionsExample/Program.cs
new file mode 100644
index 00000000..40375a01
--- /dev/null
+++ b/eg/SourceGenerator/OptionsExample/Program.cs
@@ -0,0 +1,44 @@
+using System;
+using DocoptNet.Generated;
+using OptionsExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args, version: "1.0.0rc2");
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Help       = {arguments.OptHelp      },
+    Verbose    = {arguments.OptVerbose   },
+    Quiet      = {arguments.OptQuiet     },
+    Repeat     = {arguments.OptRepeat    },
+    File       = {arguments.OptFile      },
+    Exclude    = {arguments.OptExclude   },
+    Select     = {arguments.OptSelect    },
+    Ignore     = {arguments.OptIgnore    },
+    ShowSource = {arguments.OptShowSource},
+    Statistics = {arguments.OptStatistics},
+    Count      = {arguments.OptCount     },
+    Benchmark  = {arguments.OptBenchmark },
+    Path       = [{string.Join(", ", arguments.ArgPath)}],
+    Doctest    = {arguments.OptDoctest   },
+    Testsuite  = {arguments.OptTestsuite },
+    Version    = {arguments.OptVersion   },
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/OptionsExample/Program.docopt.txt b/eg/SourceGenerator/OptionsExample/Program.docopt.txt
new file mode 100644
index 00000000..f7547ae9
--- /dev/null
+++ b/eg/SourceGenerator/OptionsExample/Program.docopt.txt
@@ -0,0 +1,31 @@
+Example of program with many options using docopt.
+
+Usage:
+  OptionsExample [-hvqrf NAME] [--exclude=PATTERNS]
+                 [--select=ERRORS | --ignore=ERRORS] [--show-source]
+                 [--statistics] [--count] [--benchmark] PATH...
+  OptionsExample (--doctest | --testsuite=DIR)
+  OptionsExample --version
+
+Arguments:
+  PATH  destination path
+
+Options:
+  -h --help            show this help message and exit
+  --version            show version and exit
+  -v --verbose         print status messages
+  -q --quiet           report only file names
+  -r --repeat          show all occurrences of the same error
+  --exclude=PATTERNS   exclude files or directories which match these comma
+                       separated patterns [default: .svn,CVS,.bzr,.hg,.git]
+  -f NAME --file=NAME  when parsing directories, only check filenames matching
+                       these comma separated patterns [default: *.py]
+  --select=ERRORS      select errors and warnings (e.g. E,W6)
+  --ignore=ERRORS      skip errors and warnings (e.g. E4,W)
+  --show-source        show source code for each error
+  --statistics         count errors and warnings
+  --count              print total number of errors and warnings to standard
+                       error and set exit code to 1 if total is not null
+  --benchmark          measure processing speed
+  --testsuite=DIR      run regression tests from dir
+  --doctest            run doctest on myself
diff --git a/eg/SourceGenerator/OptionsShortcutExample/OptionsShortcutExample.csproj b/eg/SourceGenerator/OptionsShortcutExample/OptionsShortcutExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/OptionsShortcutExample/OptionsShortcutExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/eg/SourceGenerator/OptionsShortcutExample/Program.cs b/eg/SourceGenerator/OptionsShortcutExample/Program.cs
new file mode 100644
index 00000000..0a4bdc86
--- /dev/null
+++ b/eg/SourceGenerator/OptionsShortcutExample/Program.cs
@@ -0,0 +1,35 @@
+using System;
+using DocoptNet.Generated;
+using OptionsShortcutExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args, version: "1.0.0rc2");
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Help    = {arguments.OptHelp   },
+    Version = {arguments.OptVersion},
+    Number  = {arguments.OptNumber },
+    Timeout = {arguments.OptTimeout},
+    Apply   = {arguments.OptApply  },
+    Q       = {arguments.OptQ      },
+    Port    = {arguments.ArgPort   },
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/OptionsShortcutExample/Program.docopt.txt b/eg/SourceGenerator/OptionsShortcutExample/Program.docopt.txt
new file mode 100644
index 00000000..f30589cf
--- /dev/null
+++ b/eg/SourceGenerator/OptionsShortcutExample/Program.docopt.txt
@@ -0,0 +1,12 @@
+Example of program which uses [options] shortcut in pattern.
+
+Usage:
+  OptionsShortcutExample [options] <port>
+
+Options:
+  -h --help                show this help message and exit
+  --version                show version and exit
+  -n, --number N           use N as a number
+  -t, --timeout TIMEOUT    set timeout TIMEOUT seconds
+  --apply                  apply changes to database
+  -q                       operate in quiet mode
diff --git a/eg/SourceGenerator/QuickExample/Program.cs b/eg/SourceGenerator/QuickExample/Program.cs
new file mode 100644
index 00000000..c91a4ff7
--- /dev/null
+++ b/eg/SourceGenerator/QuickExample/Program.cs
@@ -0,0 +1,37 @@
+using System;
+using DocoptNet.Generated;
+using QuickExample;
+
+ProgramArguments arguments;
+
+try
+{
+    arguments = ProgramArguments.Apply(args, version: "1.0.0rc2");
+}
+catch (DocoptExitException e)
+{
+    Console.WriteLine(e.Message);
+    return e.ErrorCode;
+}
+catch (DocoptInputErrorException e)
+{
+    Console.Error.WriteLine(e);
+    return 0xbd;
+}
+
+foreach (var (name, value) in arguments)
+    Console.WriteLine($"{name} = {value}");
+
+Console.WriteLine($@"{{
+    Tcp     = {arguments.CmdTcp    },
+    Host    = {arguments.ArgHost   },
+    Port    = {arguments.ArgPort   },
+    Timeout = {arguments.OptTimeout},
+    Serial  = {arguments.CmdSerial },
+    Baud    = {arguments.OptBaud   },
+    H       = {arguments.OptH      },
+    Help    = {arguments.OptHelp   },
+    Version = {arguments.OptVersion},
+}}");
+
+return 0;
diff --git a/eg/SourceGenerator/QuickExample/Program.docopt.txt b/eg/SourceGenerator/QuickExample/Program.docopt.txt
new file mode 100644
index 00000000..3123c1f9
--- /dev/null
+++ b/eg/SourceGenerator/QuickExample/Program.docopt.txt
@@ -0,0 +1,4 @@
+Usage:
+  QuickExample tcp <host> <port> [--timeout=<seconds>]
+  QuickExample serial <port> [--baud=9600] [--timeout=<seconds>]
+  QuickExample -h | --help | --version
diff --git a/eg/SourceGenerator/QuickExample/QuickExample.csproj b/eg/SourceGenerator/QuickExample/QuickExample.csproj
new file mode 100644
index 00000000..ca2efb44
--- /dev/null
+++ b/eg/SourceGenerator/QuickExample/QuickExample.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.targets" />
+
+</Project>
diff --git a/global.json b/global.json
index a46dc9b0..988a308f 100644
--- a/global.json
+++ b/global.json
@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "5.0.100",
+    "version": "5.0.300",
     "rollForward": "latestFeature"
   }
 }
diff --git a/src/DocoptNet.CodeGeneration/AnalyzerReleases.Shipped.md b/src/DocoptNet.CodeGeneration/AnalyzerReleases.Shipped.md
new file mode 100644
index 00000000..d567f142
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/AnalyzerReleases.Shipped.md
@@ -0,0 +1,3 @@
+; Shipped analyzer releases
+; https://github.com/dotnet/roslyn-analyzers/blob/master/src/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md
+
diff --git a/src/DocoptNet.CodeGeneration/AnalyzerReleases.Unshipped.md b/src/DocoptNet.CodeGeneration/AnalyzerReleases.Unshipped.md
new file mode 100644
index 00000000..0777b335
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/AnalyzerReleases.Unshipped.md
@@ -0,0 +1,8 @@
+; Unshipped analyzer release
+; https://github.com/dotnet/roslyn-analyzers/blob/master/src/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md
+
+### New Rules
+
+Rule ID | Category | Severity | Notes
+--------|----------|----------|-------
+DCPT0001 | Docopt | Error | SyntaxError
diff --git a/src/DocoptNet.CodeGeneration/CSharpSourceBuilder.cs b/src/DocoptNet.CodeGeneration/CSharpSourceBuilder.cs
new file mode 100644
index 00000000..14afe587
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/CSharpSourceBuilder.cs
@@ -0,0 +1,281 @@
+#nullable enable
+
+#region Copyright (c) 2021 Atif Aziz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+namespace DocoptNet.CodeGeneration
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Diagnostics;
+    using System.Text;
+
+    sealed class CSharpSourceBuilder :
+        CSharpSourceBuilder.IStatementFlow,
+        CSharpSourceBuilder.IBlockFlow,
+        CSharpSourceBuilder.IControlBlockFlow,
+        CSharpSourceBuilder.ISwitchFlow,
+        CSharpSourceBuilder.ISwitchCasesFlow
+    {
+        bool _skipNextNewLine;
+
+        public CSharpSourceBuilder() : this(new()) { }
+        public CSharpSourceBuilder(StringBuilder sb) => StringBuilder = sb;
+
+        public StringBuilder StringBuilder { get; }
+
+        public int Level { get; private set; }
+        public bool IsNewLine { get; private set; } = true;
+
+        CSharpSourceBuilder Indent
+        {
+            get
+            {
+                Level++;
+                return this;
+            }
+        }
+
+        CSharpSourceBuilder Outdent
+        {
+            get
+            {
+                if (Level == 0)
+                    throw new InvalidOperationException();
+                Level--;
+                return this;
+            }
+        }
+
+        StringBuilder OnAppending()
+        {
+            if (!IsNewLine)
+                return StringBuilder;
+            IsNewLine = false;
+            return StringBuilder.Append(' ', Level * 4);
+        }
+
+        void Append(char value) => OnAppending().Append(value);
+        void Append(string value) => OnAppending().Append(value);
+        void Append(int value) => OnAppending().Append(value);
+
+        void AppendLine()
+        {
+            if (_skipNextNewLine)
+            {
+                _skipNextNewLine = false;
+                return;
+            }
+
+            StringBuilder.AppendLine();
+            IsNewLine = true;
+        }
+
+        public override string ToString() => StringBuilder.ToString();
+
+        public CSharpSourceBuilder SkipNextNewLine { get { _skipNextNewLine = true; return this; } }
+
+        [Conditional("DEBUG")]
+        void AssertSame(CSharpSourceBuilder other) => Debug.Assert(ReferenceEquals(this, other));
+
+        public CSharpSourceBuilder this[string code] { get { Append(code); return this; } }
+        public CSharpSourceBuilder this[char code] { get { Append(code); return this; } }
+        public CSharpSourceBuilder this[CSharpSourceBuilder code] { get { AssertSame(code); return this; } }
+
+        public CSharpSourceBuilder Blank() => this;
+        public CSharpSourceBuilder NewLine { get { AppendLine(); return this; } }
+
+        static readonly char[] ForbiddenRegularStringLiteralChars =
+        {
+            '"', '\\', '\r', '\n',
+            '\u0085', // Next line character
+            '\u2028', // Line separator character
+            '\u2029', // Paragraph separator character
+        };
+
+        const string Quote = "\"";
+
+        public CSharpSourceBuilder Literal(string value) =>
+            //
+            // https://github.com/dotnet/csharplang/blob/f1533732b093e54665471fcf92aba5c77f0acedd/spec/lexical-structure.md
+            //
+            // single_regular_string_literal_character
+            //     : '<Any character except " (U+0022), \\ (U+005C), and new_line_character>'
+            //     ;
+            // new_line_character
+            //     : '<Carriage return character (U+000D)>'
+            //     | '<Line feed character (U+000A)>'
+            //     | '<Next line character (U+0085)>'
+            //     | '<Line separator character (U+2028)>'
+            //     | '<Paragraph separator character (U+2029)>'
+            //     ;
+            //
+            _ = value.IndexOfAny(ForbiddenRegularStringLiteralChars) >= 0
+              ? this['@'][Quote][value.Replace(Quote, Quote + Quote)][Quote]
+              : this[Quote][value][Quote];
+
+        public CSharpSourceBuilder Literal(int value) { Append(value); return this; }
+
+        public CSharpSourceBuilder Each<T>(IEnumerable<T> source, Func<CSharpSourceBuilder, T, int, CSharpSourceBuilder> builder)
+        {
+            var i = 0;
+            foreach (var item in source)
+                builder(this, item, i++);
+            return this;
+        }
+
+        CSharpSourceBuilder Equal => this[" = "];
+
+        public CSharpSourceBuilder Using(string ns) =>
+            this["using "][ns].EndStatement;
+
+        public CSharpSourceBuilder Using(string alias, string typeName) =>
+            this["using "][alias].Equal[typeName].EndStatement;
+
+        public CSharpSourceBuilder UsingStatic(string typeName) =>
+            this["using "].Static[typeName].EndStatement;
+
+        public CSharpSourceBuilder Namespace(string name) =>
+            this["namespace "][name].NewLine.BlockStart;
+
+        public CSharpSourceBuilder Null    => this["null"];
+        public CSharpSourceBuilder True    => this["true"];
+        public CSharpSourceBuilder False   => this["false"];
+
+        public CSharpSourceBuilder Break   => this["break"].EndStatement;
+
+        public CSharpSourceBuilder Partial => this["partial "];
+        public CSharpSourceBuilder Static  => this["static "];
+        public CSharpSourceBuilder Class   => this["class "];
+        public CSharpSourceBuilder Public  => this["public "];
+        public CSharpSourceBuilder Yield   => this["yield "];
+        public CSharpSourceBuilder New     => this["new "];
+
+        public IControlBlockFlow If      => this["if "].Control;
+        public IControlBlockFlow While   => this["while "].Control;
+        public IControlBlockFlow ForEach => this["foreach "].Control;
+
+        public CSharpSourceBuilder BlockStart => this['{'].NewLine.Indent;
+        public CSharpSourceBuilder BlockEnd   => Outdent['}'].NewLine;
+
+        public CSharpSourceBuilder EndStatement => this[';'].NewLine;
+
+        public CSharpSourceBuilder LineComment(string comment) =>
+            this["// "][comment].NewLine;
+
+        public CSharpSourceBuilder Const(string name, string value) =>
+            this["const string "].Assign(name)[Literal(value)];
+
+        public IStatementFlow Return => this["return "];
+        public IStatementFlow Var(string name) => this["var "].Assign(name);
+        public IStatementFlow Assign(string name) => this[name].Equal;
+        public IStatementFlow Assign(CSharpSourceBuilder code) { AssertSame(code); return Equal; }
+
+        public IBlockFlow Block => BlockStart;
+
+        public interface IBlockFlow
+        {
+            CSharpSourceBuilder this[string code] { get; }
+            CSharpSourceBuilder this[CSharpSourceBuilder code] { get; }
+        }
+
+        CSharpSourceBuilder IBlockFlow.this[string code] => BlockFlow(this[code]);
+        CSharpSourceBuilder IBlockFlow.this[CSharpSourceBuilder code] => BlockFlow(code);
+        CSharpSourceBuilder BlockFlow(CSharpSourceBuilder code) { AssertSame(code); return BlockEnd; }
+
+        public interface IStatementFlow
+        {
+            CSharpSourceBuilder this[string code] { get; }
+            CSharpSourceBuilder this[CSharpSourceBuilder code] { get; }
+        }
+
+        CSharpSourceBuilder IStatementFlow.this[string code] => StatementFlow(this[code]);
+        CSharpSourceBuilder IStatementFlow.this[CSharpSourceBuilder code] => StatementFlow(code);
+        CSharpSourceBuilder StatementFlow(CSharpSourceBuilder code) { AssertSame(code); return EndStatement; }
+
+        IControlBlockFlow Control => this['('];
+
+        public interface IControlBlockFlow
+        {
+            IBlockFlow this[string code] { get; }
+            IBlockFlow this[CSharpSourceBuilder code] { get; }
+        }
+
+        IBlockFlow IControlBlockFlow.this[string code] => ControlBlockFlow(this[code]);
+        IBlockFlow IControlBlockFlow.this[CSharpSourceBuilder code] => ControlBlockFlow(code);
+        IBlockFlow ControlBlockFlow(CSharpSourceBuilder code) { AssertSame(code); return this[')'].NewLine.Block; }
+
+        public ISwitchFlow Switch => this["switch ("];
+
+        public interface ISwitchFlow
+        {
+            ISwitchCasesFlow this[string code] { get; }
+            ISwitchCasesFlow this[CSharpSourceBuilder code] { get; }
+        }
+
+        ISwitchCasesFlow ISwitchFlow.this[string code] => SwitchFlow(this[code]);
+        ISwitchCasesFlow ISwitchFlow.this[CSharpSourceBuilder code] => SwitchFlow(code);
+        ISwitchCasesFlow SwitchFlow(CSharpSourceBuilder code) { AssertSame(code); return this[')'].NewLine.BlockStart; }
+
+        public interface ISwitchCasesFlow
+        {
+            CSharpSourceBuilder Cases<T, TArg>(IEnumerable<T> source,
+                                               TArg arg,
+                                               Func<TArg, T, int, SwitchCaseChoice> caseChooser,
+                                               Func<CSharpSourceBuilder, TArg, T, CSharpSourceBuilder> caseBlock);
+        }
+
+        CSharpSourceBuilder ISwitchCasesFlow.Cases<T, TArg>(
+            IEnumerable<T> source,
+            TArg arg,
+            Func<TArg, T, int, SwitchCaseChoice> caseChooser,
+            Func<CSharpSourceBuilder, TArg, T, CSharpSourceBuilder> caseBlock)
+        {
+            var i = 0;
+            foreach (var item in source)
+            {
+                _ = this["case "][caseChooser(arg, item, i++) switch
+                    {
+                        { IsInteger: true, Integer: var n } => Literal(n),
+                        { IsString: true, String: var str } => Literal(str),
+                        _ => throw new NotSupportedException(),
+                    }]
+                    [':'][caseBlock(this, arg, item)].Break;
+            }
+
+            return BlockEnd;
+        }
+
+        public readonly struct SwitchCaseChoice
+        {
+            readonly int _num;
+            readonly string? _str;
+
+            SwitchCaseChoice(int num, string? str) => (_num, _str) = (num, str);
+
+            public static SwitchCaseChoice Choose(int num) => new(num, null);
+            public static SwitchCaseChoice Choose(string str) => new(0, str);
+
+            public bool IsInteger => !IsString;
+            public bool IsString => _str is not null;
+
+            public int Integer => IsInteger ? _num : throw new InvalidOperationException();
+            public string String => _str ?? throw new InvalidOperationException();
+
+            public override string ToString() => IsInteger ? Integer.ToString() : String;
+        }
+    }
+}
diff --git a/src/DocoptNet.CodeGeneration/DocoptNet.CodeGeneration.csproj b/src/DocoptNet.CodeGeneration/DocoptNet.CodeGeneration.csproj
new file mode 100644
index 00000000..32d9c646
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/DocoptNet.CodeGeneration.csproj
@@ -0,0 +1,39 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>annotations</Nullable>
+    <IsRoslynComponent>true</IsRoslynComponent>
+    <IsPackable>true</IsPackable>
+    <AssemblyOriginatorKeyFile>..\DocoptNet\DocoptNet.snk</AssemblyOriginatorKeyFile>
+    <SignAssembly>true</SignAssembly>
+    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0" PrivateAssets="all" />
+    <PackageReference Include="Nullable" Version="1.3.0">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <!-- Package the generator in the analyzer directory of the nuget package -->
+    <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <AdditionalFiles Include="AnalyzerReleases.Shipped.md" />
+    <AdditionalFiles Include="AnalyzerReleases.Unshipped.md" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="..\DocoptNet\*.cs" Link="DocoptNet\%(Filename)%(Extension)" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <EmbeddedResource Include="..\DocoptNet\*.cs" Link="Generated\%(Filename)%(Extension)" />
+  </ItemGroup>
+
+</Project>
diff --git a/src/DocoptNet.CodeGeneration/DocoptNet.CodeGeneration.targets b/src/DocoptNet.CodeGeneration/DocoptNet.CodeGeneration.targets
new file mode 100644
index 00000000..72b91c33
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/DocoptNet.CodeGeneration.targets
@@ -0,0 +1,19 @@
+<Project>
+
+  <Target Name="_InjectDocoptAdditionalFiles" BeforeTargets="PrepareForBuild;CompileDesignTime;GenerateMSBuildEditorConfigFileShouldRun">
+    <ItemGroup>
+      <AdditionalFiles Include="@(None)"
+                       Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('%(Filename)%(Extension)', 'docopt\.txt$'))"
+                       SourceItemType="docopt"
+                       KeepMetadata="Name" />
+    </ItemGroup>
+  </Target>
+
+  <ItemGroup>
+    <CompilerVisibleProperty Include="RootNamespace" />
+    <CompilerVisibleProperty Include="DebugDocoptNet" />
+    <CompilerVisibleItemMetadata Include="AdditionalFiles" MetadataName="SourceItemType" />
+    <CompilerVisibleItemMetadata Include="AdditionalFiles" MetadataName="Name" />
+  </ItemGroup>
+
+</Project>
diff --git a/src/DocoptNet.CodeGeneration/Extensions.cs b/src/DocoptNet.CodeGeneration/Extensions.cs
new file mode 100644
index 00000000..6e03e552
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/Extensions.cs
@@ -0,0 +1,117 @@
+#region Copyright (c) 2021 Atif Aziz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#nullable enable
+
+namespace DocoptNet.CodeGeneration
+{
+    using System.Diagnostics;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.Diagnostics;
+
+    // Inspiration & credit:
+    // https://github.com/devlooped/ThisAssembly/blob/43eb32fa24c25ddafda1058a53857ea3e305296a/src/GeneratorExtension.cs
+
+    static partial class Extensions
+    {
+        public static void LaunchDebuggerIfFlagged(this GeneratorExecutionContext context,
+                                                   string generatorName) =>
+            context.AnalyzerConfigOptions.GlobalOptions.LaunchDebuggerIfFlagged(generatorName);
+
+        public static void LaunchDebuggerIfFlagged(this AnalyzerConfigOptions options,
+                                                   string generatorName)
+        {
+            if (options.IsFlagged("build_property.DebugSourceGenerators") ||
+                options.IsFlagged("build_property.Debug" + generatorName))
+            {
+                Debugger.Launch();
+            }
+        }
+
+        public static bool IsFlagged(this AnalyzerConfigOptions options, string name) =>
+            options.TryGetValue(name, out var s) && bool.TryParse(s, out var flag) && flag;
+    }
+}
+
+#region (c) West Wind Technologies, 2008 - 2009
+/*
+ **************************************************************
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ **************************************************************
+ */
+#endregion
+
+namespace DocoptNet.CodeGeneration
+{
+    using System;
+    using System.Text;
+
+    // Following extensions were adapted from:
+    // https://weblog.west-wind.com/posts/2018/Nov/30/Returning-an-XML-Encoded-String-in-NET
+
+    partial class Extensions
+    {
+        public static string EncodeXmlText(this string str) => str.EncodeXmlText(attribute: false);
+        public static string EncodeXmlAttributeValue(this string str) => str.EncodeXmlText(attribute: true);
+
+        static string EncodeXmlText(this string str, bool attribute)
+        {
+            StringBuilder? sb = null;
+
+            StringBuilder StringBuilder() => sb ??= new StringBuilder(str.Length);
+            void Append(string s) => StringBuilder().Append(s);
+            void AppendChar(char ch) => StringBuilder().Append(ch);
+
+            foreach (var ch in str)
+            {
+                switch (attribute, ch)
+                {
+                    case (_, '<')    : Append("&lt;"); break;
+                    case (_, '>')    : Append("&gt;"); break;
+                    case (_, '&')    : Append("&amp;"); break;
+                    case (true, '"') : Append("&quot;"); break;
+                    case (true, '\''): Append("&apos;"); break;
+                    case (true, '\n'): Append("&#xA;"); break;
+                    case (true, '\r'): Append("&#xD;"); break;
+                    case (true, '\t'): Append("&#x9;"); break;
+                    case (_, < ' ')  : throw new ArgumentException($"Character U+{(int)ch:X4} is forbidden in XML.", nameof(str));
+                    default          : AppendChar(ch); break;
+                }
+            }
+
+            return sb?.ToString() ?? str;
+        }
+    }
+}
diff --git a/src/DocoptNet.CodeGeneration/SourceGenerator.cs b/src/DocoptNet.CodeGeneration/SourceGenerator.cs
new file mode 100644
index 00000000..17634f3f
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/SourceGenerator.cs
@@ -0,0 +1,319 @@
+#nullable enable
+
+#region Copyright (c) 2021 Atif Aziz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+namespace DocoptNet.CodeGeneration
+{
+    using System;
+    using System.IO;
+    using System.Linq;
+    using System.Text;
+    using System.Text.RegularExpressions;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.Text;
+    using Argument = DocoptNet.Argument;
+    using Unit = System.ValueTuple;
+
+    [Generator]
+    public sealed class SourceGenerator : ISourceGenerator
+    {
+        static readonly DiagnosticDescriptor SyntaxError =
+            new(id: "DCPT0001",
+                title: "Syntax error",
+                messageFormat: "Syntax error: {0}",
+                category: "Docopt",
+                DiagnosticSeverity.Error,
+                isEnabledByDefault: true);
+
+        public void Initialize(GeneratorInitializationContext context) {}
+
+        static class Metadata
+        {
+            const string Prefix = "build_metadata.AdditionalFiles.";
+            public const string SourceItemType = Prefix + nameof(SourceItemType);
+            public const string Name = Prefix + nameof(Name);
+        }
+
+        public void Execute(GeneratorExecutionContext context)
+        {
+            context.LaunchDebuggerIfFlagged(nameof(DocoptNet));
+
+            context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.RootNamespace", out var ns);
+
+            var docopts =
+                from at in context.AdditionalFiles
+                select context.AnalyzerConfigOptions.GetOptions(at) is {} options
+                    && options.TryGetValue(Metadata.SourceItemType, out var type)
+                    && "docopt".Equals(type, StringComparison.OrdinalIgnoreCase)
+                    && at.GetText() is {} text
+                     ? new
+                       {
+                           FilePath = at.Path,
+                           Name = options.TryGetValue(Metadata.Name, out var name)
+                                  && !string.IsNullOrWhiteSpace(name)
+                                ? name
+                                : Path.GetFileName(at.Path).Partition(".").Item1,
+                           Text = text,
+                       }
+                     : null
+                into e
+                where e is not null
+                select e;
+
+            var added = false;
+
+            foreach (var docopt in docopts)
+            {
+                try
+                {
+                    if (Generate(ns, docopt.Name, docopt.Text) is { Length: > 0 } source)
+                    {
+                        added = true;
+                        context.AddSource(docopt.Name + "Arguments.cs", source);
+                    }
+                }
+                catch (DocoptLanguageErrorException e)
+                {
+                    var args = Regex.Replace(e.Message, @"\r?\n", @"\n");
+                    context.ReportDiagnostic(Diagnostic.Create(SyntaxError, Location.None, args));
+                }
+            }
+
+            if (added)
+            {
+                const string resourceNamespace = "DocoptNet.CodeGeneration.Generated.";
+                var assembly = GetType().Assembly;
+                foreach (var (rn, fn) in from rn in assembly.GetManifestResourceNames()
+                                         where rn.StartsWith(resourceNamespace) && rn.EndsWith(".cs")
+                                         select (rn, rn.Substring(resourceNamespace.Length)))
+                {
+                    using var stream = assembly.GetManifestResourceStream(rn)!;
+                    using var reader = new StreamReader(stream);
+                    var source = Regex.Replace(reader.ReadToEnd(), @"(?<=\bnamespace\s+)DocoptNet(?:\.Generated)?\b", "DocoptNet.Generated");
+                    context.AddSource(fn, SourceText.From(source, Utf8BomlessEncoding));
+                }
+            }
+        }
+
+        static readonly SourceText EmptySourceText = SourceText.From(string.Empty);
+        static readonly Encoding Utf8BomlessEncoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
+
+        static readonly string[] Vars = "abcdefghijklmnopqrstuvwxyz".Select(ch => ch.ToString()).ToArray();
+
+        public static SourceText Generate(string? ns, string name, SourceText text) =>
+            Generate(ns, name, text, null);
+
+        public static SourceText Generate(string? ns, string name, SourceText text, Encoding? outputEncoding)
+        {
+            if (text.Length == 0)
+                return EmptySourceText;
+
+            var helpText = text.ToString();
+            var code = new CSharpSourceBuilder();
+            Generate(code, ns is { Length: 0 } ? null : ns, name, helpText);
+            return new StringBuilderSourceText(code.StringBuilder, outputEncoding ?? text.Encoding ?? Utf8BomlessEncoding);
+        }
+
+        static void Generate(CSharpSourceBuilder code, string? ns, string name, string helpText)
+        {
+            var (pattern, options, usage) = Docopt.ParsePattern(helpText);
+
+            var leaves = Docopt.GetFlatPatterns(helpText)
+                               .GroupBy(p => p.Name)
+                               .Select(g => (LeafPattern)g.First())
+                               .ToList();
+
+            const string helpConstName = "Help";
+            const string usageConstName = "Usage";
+
+            code["#nullable enable annotations"].NewLine
+
+                .NewLine
+                .Using("System.Collections")
+                .Using("System.Collections.Generic")
+                .Using("System.Linq")
+                .Using("DocoptNet.Generated")
+                .Using("Leaves", "DocoptNet.Generated.ReadOnlyList<DocoptNet.Generated.LeafPattern>")
+                .UsingStatic("DocoptNet.Generated.GeneratedSourceModule")
+
+                .NewLine
+                [ns is not null ? code.Namespace(ns) : code.Blank()]
+
+                .Partial.Class[name]["Arguments : IEnumerable<KeyValuePair<string, object?>>"].NewLine.Block[code
+                    .Public.Const(helpConstName, helpText)
+
+                    .NewLine
+                    .Public.Const(usageConstName, usage)
+
+                    .NewLine
+                    .Public.Static[name]["Arguments Apply(IEnumerable<string> args, bool help = true, object? version = null, bool optionsFirst = false)"]
+                    .NewLine.Block[code
+                        .Var("options")[
+                            code.New["List<Option>"].NewLine
+                                .Block[code.Each(options,
+                                                 static (code, option, _) =>
+                                                     code.New["Option("][option.ShortName is {} sn ? code.Literal(sn) : code.Null][", "]
+                                                         [option.LongName is {} ln ? code.Literal(ln) : code.Null][", "]
+                                                         .Literal(option.ArgCount)[", "]
+                                                         [Value(code, option.Value)]["),"].NewLine).SkipNextNewLine]]
+                        .Var("left")["ParseArgv(" + helpConstName + ", args, options, optionsFirst, help, version)"]
+                        .Var("required")[code.New["RequiredMatcher(1, left, "].New["Leaves()"][')']]
+                        ["Match(ref required)"].EndStatement
+                        .Var("collected")["GetSuccessfulCollection(required, " + usageConstName + ")"]
+                        .Var("result")[code.New[name]["Arguments()"]]
+                        [leaves.Any()
+                             ? code.NewLine
+                                   .ForEach["var leaf in collected"][
+                                        code.Var("value")["leaf.Value is { IsStringList: true } ? ((StringList)leaf.Value).Reverse() : leaf.Value"]
+                                            .Switch["leaf.Name"]
+                                            .Cases(leaves, default(Unit),
+                                                   static (_, leaf, _) => CSharpSourceBuilder.SwitchCaseChoice.Choose(leaf.Name),
+                                                   static (code, _, leaf) =>
+                                                       code[' ']
+                                                          .Assign(code["result."][InferPropertyName(leaf)])[
+                                                               code['(']
+                                                                   [leaf switch { Option   { Value: { IsString: true } } => "string",
+                                                                                  Argument { Value: { IsNone: true } } or Option { ArgCount: not 0, Value: { Kind: not ValueKind.StringList } } => "string?",
+                                                                                  { Value: { Kind: var kind } } => MapType(kind) }]
+                                                                   [")value"].SkipNextNewLine][' '])]
+                             : code.Blank()
+                        ]
+
+                        .NewLine
+                        .Return["result"]
+
+                        .NewLine
+                        ["static void Match(ref RequiredMatcher required)"].NewLine.Block[
+                            GeneratePatternMatchingCode(code, pattern, "required")]
+                    ] // Apply
+
+                    .NewLine
+                    ["IEnumerator<KeyValuePair<string, object?>> GetEnumerator()"].NewLine.Block[
+                        leaves.Any() ? code.Each(leaves, static (code, p, _) => code.Yield.Return[code["KeyValuePair.Create("].Literal(p.Name)[", (object?)"][InferPropertyName(p)][')']])
+                                     : code.Yield.Break]
+
+                    .NewLine
+                    ["IEnumerator<KeyValuePair<string, object?>> IEnumerable<KeyValuePair<string, object?>>.GetEnumerator() => GetEnumerator()"].EndStatement
+                    ["IEnumerator IEnumerable.GetEnumerator() => GetEnumerator()"].EndStatement
+
+                    .Each(from p in leaves
+                          select (Name: InferPropertyName(p), Leaf: p),
+                          static (code, e, _) =>
+                              code.NewLine["/// <summary><c>"][e.Leaf.ToString().EncodeXmlText()]["</c></summary>"]
+                                  .NewLine
+                                  .Public[e.Leaf switch
+                                   {
+                                       Option { Value: { IsString: true } str } => code["string "][e.Name][" { get; private set; } = "].Literal((string)str).SkipNextNewLine.EndStatement,
+                                       Argument { Value: { IsNone: true } } or Option { ArgCount: not 0, Value: { Kind: not ValueKind.StringList } } => code["string? "][e.Name][" { get; private set; }"],
+                                       { Value: { Object: StringList list } } => code["StringList "][e.Name][" { get; private set; } = "][Value(code, list.Reverse())].SkipNextNewLine.EndStatement,
+                                       { Value: { Kind: var kind } } => code[MapType(kind)][' '][e.Name][" { get; private set; }"],
+                                   }]
+                                  .NewLine)
+                ] // class
+                [ns is not null ? code.BlockEnd : code.Blank()]
+                .Blank();
+
+            static CSharpSourceBuilder GeneratePatternMatchingCode(CSharpSourceBuilder code,
+                                                                   Pattern pattern, string pmv, int level = 0)
+            {
+                if (level >= 26) // todo proper diagnostics reporting
+                    throw new NotSupportedException();
+
+                code.LineComment(pattern?.ToString() ?? string.Empty);
+
+                switch (pattern)
+                {
+                    case BranchPattern { Children: { } children }:
+                    {
+                        var matcher = pattern switch
+                        {
+                            Either => nameof(EitherMatcher),
+                            OneOrMore => nameof(OneOrMoreMatcher),
+                            Optional => nameof(OptionalMatcher),
+                            Required => nameof(RequiredMatcher),
+                            _ => throw new ArgumentOutOfRangeException(nameof(pattern))
+                        };
+                        var mv = Vars[level++];
+                        code.Var(mv)[code.New[matcher]['('].Literal(children.Count)[", "][pmv][".Left, "][pmv][".Collected)"]]
+                            .While[code[mv][".Next()"]][
+                                (pattern.Children.Count switch
+                                {
+                                    > 1 => code.Switch[code[mv][".Index"]]
+                                               .Cases(children, arg: (MatchVar: mv, Level: level),
+                                                      static (_, _, i) => CSharpSourceBuilder.SwitchCaseChoice.Choose(i),
+                                                      static (code, arg, child) =>
+                                                          code.NewLine.Block[GeneratePatternMatchingCode(code, child, arg.MatchVar, arg.Level)]),
+                                    1 => GeneratePatternMatchingCode(code, children[0], mv, level),
+                                    _ => code.Blank(),
+                                })
+                                .If[code['!'][mv][".LastMatched"]][
+                                    code.Break]]
+                            [pmv][".Fold(" + mv + ".Result)"].EndStatement.Blank();
+                        break;
+                    }
+                    case LeafPattern { Name: var name } leaf:
+                    {
+                        var lfn = leaf switch
+                        {
+                            Command  => nameof(PatternMatcher.MatchCommand),
+                            Argument => nameof(PatternMatcher.MatchArgument),
+                            Option   => nameof(PatternMatcher.MatchOption),
+                            _ => throw new NotImplementedException()
+                        };
+                        code[pmv][".Match(" + "PatternMatcher."][lfn][", "].Literal(name)[", ValueKind."][leaf.Value.Kind.ToString()][')'].EndStatement.Blank();
+                        break;
+                    }
+                }
+
+                return code;
+            }
+
+            static string InferPropertyName(LeafPattern leaf) =>
+                leaf switch
+                {
+                    Command  { Name: var name } => $"Cmd{GenerateCodeHelper.ConvertToPascalCase(name.ToLowerInvariant())}",
+                    Argument { Name: var name } => $"Arg{GenerateCodeHelper.ConvertToPascalCase(name.Replace("<", "").Replace(">", "").ToLowerInvariant())}",
+                    Option   { Name: var name } => $"Opt{GenerateCodeHelper.ConvertToPascalCase(name.ToLowerInvariant())}",
+                    var p => throw new NotSupportedException($"Unsupported pattern: {p}")
+                };
+
+            static string MapType(ValueKind kind) =>
+                kind switch
+                {
+                    ValueKind.Boolean    => "bool",
+                    ValueKind.Integer    => "int",
+                    ValueKind.String     => "string?",
+                    ValueKind.StringList => nameof(StringList),
+                    _ => throw new ArgumentOutOfRangeException(nameof(kind), kind, null)
+                };
+
+            static CSharpSourceBuilder Value(CSharpSourceBuilder code, Value value) =>
+                value.TryAsStringList(out var items) && items.Count > 0
+                ? code["StringList.TopBottom("].Each(items, static (code, item, i) => (i > 0 ? code[", "] : code.Blank()).Literal(item))[')']
+                : value.Object switch
+                  {
+                      null => code.Null,
+                      int n => code.Literal(n),
+                      string s => code.Literal(s),
+                      true => code.True,
+                      false => code.False,
+                      StringList { IsEmpty: true } => code["StringList.Empty"],
+                      _ => throw new NotSupportedException(), // todo emit diagnostic
+                  };
+        }
+    }
+}
diff --git a/src/DocoptNet.CodeGeneration/StringBuilderSourceText.cs b/src/DocoptNet.CodeGeneration/StringBuilderSourceText.cs
new file mode 100644
index 00000000..aeecdf58
--- /dev/null
+++ b/src/DocoptNet.CodeGeneration/StringBuilderSourceText.cs
@@ -0,0 +1,40 @@
+#region Copyright (c) 2021 Atif Aziz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#nullable enable
+
+namespace DocoptNet.CodeGeneration
+{
+    using System.Text;
+    using Microsoft.CodeAnalysis.Text;
+
+    sealed class StringBuilderSourceText : SourceText
+    {
+        readonly StringBuilder _builder;
+
+        public StringBuilderSourceText(StringBuilder builder, Encoding? encoding = null) =>
+            (_builder, Encoding) = (builder, encoding);
+
+        public override Encoding? Encoding { get; }
+        public override int Length => _builder.Length;
+        public override char this[int position] => _builder[position];
+
+        public override string ToString(TextSpan span) => _builder.ToString(span.Start, span.Length);
+
+        public override void CopyTo(int sourceIndex, char[] destination, int destinationIndex, int count) =>
+            _builder.CopyTo(sourceIndex, destination, destinationIndex, count);
+    }
+}
diff --git a/src/DocoptNet/BranchPatterns.cs b/src/DocoptNet/BranchPatterns.cs
index a6301911..dafd43bd 100644
--- a/src/DocoptNet/BranchPatterns.cs
+++ b/src/DocoptNet/BranchPatterns.cs
@@ -52,7 +52,11 @@ public Optional(params Pattern[] patterns) : base(patterns) { }
     }
 
     // Marker/placeholder for [options] shortcut.
-    class OptionsShortcut : Optional { }
+    class OptionsShortcut : Optional
+    {
+        // TODO consider single pattern
+        public OptionsShortcut(params Pattern[] patterns) : base(patterns) { }
+    }
 
     class Either : BranchPattern
     {
@@ -61,6 +65,7 @@ public Either(params Pattern[] patterns) : base(patterns) { }
 
     class OneOrMore : BranchPattern
     {
+        // TODO consider single pattern
         public OneOrMore(params Pattern[] patterns) : base(patterns) { }
     }
 }
diff --git a/src/DocoptNet/Docopt.cs b/src/DocoptNet/Docopt.cs
index 8a92bb4f..eaaefad3 100644
--- a/src/DocoptNet/Docopt.cs
+++ b/src/DocoptNet/Docopt.cs
@@ -176,7 +176,7 @@ where p is (true, _)
             return nodes.ToArray();
         }
 
-        static IEnumerable<Pattern> GetFlatPatterns(string doc)
+        internal static IEnumerable<Pattern> GetFlatPatterns(string doc)
         {
             var usageSections = ParseSection("usage:", doc);
             if (usageSections.Length == 0)
diff --git a/src/DocoptNet/GenerateCodeHelper.cs b/src/DocoptNet/GenerateCodeHelper.cs
index dcfe5633..bc9a988b 100644
--- a/src/DocoptNet/GenerateCodeHelper.cs
+++ b/src/DocoptNet/GenerateCodeHelper.cs
@@ -9,14 +9,36 @@ public static string ConvertToPascalCase(string s)
             var result = "";
             for (var i = 0; i < s.Length; i++)
             {
-                if(s[i] is '-' or ' ')
+                var replacement = s[i] switch
                 {
+                    '-' or ' ' when i > 0 => string.Empty,
+                    '-' when i == 0 && s.Length == 1 => "Minus",
+                    '!' => "Exclamation",
+                    '#' => "Hash",
+                    '$' => "Dollar",
+                    '%' => "Percent",
+                    '&' => "Ampersand",
+                    '*' => "Star",
+                    '+' => "Plus",
+                    ',' => "Comma",
+                    '.' => "Dot",
+                    '/' => "Slash",
+                    ':' => "Colon",
+                    ';' => "SemiColon",
+                    '=' => "Equal",
+                    '?' => "Question",
+                    _ => null,
+                };
+                if (replacement is {} r)
+                {
+                    result += r;
                     makeUpperCase = true;
-                    continue;
                 }
-
-                result += makeUpperCase ? char.ToUpperInvariant(s[i]) : s[i];
-                makeUpperCase = false;
+                else if (s[i] is >= 'A' and <= 'Z' or >= 'a' and <= 'z' or >= '0' and <= '9')
+                {
+                    result += makeUpperCase && char.IsLower(s, i) ? char.ToUpperInvariant(s[i]) : s[i];
+                    makeUpperCase = false;
+                }
             }
 
             return result;
diff --git a/src/DocoptNet/GeneratedSourceModule.cs b/src/DocoptNet/GeneratedSourceModule.cs
new file mode 100644
index 00000000..1ae6333a
--- /dev/null
+++ b/src/DocoptNet/GeneratedSourceModule.cs
@@ -0,0 +1,28 @@
+#nullable enable
+
+namespace DocoptNet
+{
+    using System.Collections.Generic;
+    using System.Linq;
+    using Leaves = ReadOnlyList<LeafPattern>;
+
+    static class GeneratedSourceModule
+    {
+        public static Leaves ParseArgv(string doc, IEnumerable<string> args, List<Option> options,
+                                       bool optionsFirst, bool help, object? version)
+        {
+            var tokens = Tokens.From(args);
+            var arguments = Docopt.ParseArgv(tokens, options, optionsFirst).AsReadOnly();
+            if (help && arguments.Any(o => o is { Name: "-h" or "--help", Value: { IsTrue: true } }))
+                throw new DocoptExitException(doc);
+            if (version is not null && arguments.Any(o => o is { Name: "--version", Value: { IsTrue: true } }))
+                throw new DocoptExitException(version.ToString());
+            return arguments;
+        }
+
+        public static Leaves GetSuccessfulCollection(RequiredMatcher a, string usage) =>
+            !a.Result || a.Left.Count > 0
+            ? throw new DocoptInputErrorException(usage)
+            : a.Collected;
+    }
+}
diff --git a/src/DocoptNet/Pattern.cs b/src/DocoptNet/Pattern.cs
index a474dde4..65df628b 100644
--- a/src/DocoptNet/Pattern.cs
+++ b/src/DocoptNet/Pattern.cs
@@ -40,7 +40,7 @@ public override bool Equals(object obj)
 // override object.GetHashCode
         public override int GetHashCode()
         {
-            return ToString().GetHashCode();
+            return ToString()!.GetHashCode();
         }
 
         public IList<Pattern> Children { get; set; }
diff --git a/src/DocoptNet/PatternMatcher.cs b/src/DocoptNet/PatternMatcher.cs
index 94ef953a..9023e071 100644
--- a/src/DocoptNet/PatternMatcher.cs
+++ b/src/DocoptNet/PatternMatcher.cs
@@ -3,138 +3,311 @@
 namespace DocoptNet
 {
     using System;
-    using System.Diagnostics;
+    using System.Collections.Generic;
     using System.Linq;
+    using Leaves = ReadOnlyList<LeafPattern>;
+
+    delegate (int Index, LeafPattern Match) LeafPatternMatcher(Leaves left, string name);
+
+    static class LeafMatcherExtensions
+    {
+        public static MatchResult Match(this LeafPatternMatcher matcher,
+                                        Leaves left, Leaves collected,
+                                        string name, ValueKind kind)
+        {
+            var (index, match) = matcher(left, name);
+            return PatternMatcher.MatchLeaf(left, collected, name, kind, index, match);
+        }
+    }
+
+    interface IBranchPatternMatcher
+    {
+        int Index { get; }
+        bool Next();
+        Leaves Left { get; }
+        Leaves Collected { get; }
+        bool Match(LeafPatternMatcher matcher, string name, ValueKind kind);
+        bool Match(Pattern pattern);
+        bool Fold(MatchResult match);
+        bool LastMatched { get; }
+        MatchResult Result { get; }
+    }
+
+    static class BranchPatternMatcher
+    {
+        public static bool Next(ref int i, int count)
+        {
+            if (i == count)
+                return false;
+            i++;
+            return true;
+        }
+    }
+
+    struct RequiredMatcher : IBranchPatternMatcher
+    {
+        readonly int _count;
+        readonly Leaves _initLeft, _initCollected;
+        int _i;
+        MatchResult? _result;
+
+        public RequiredMatcher(int count, Leaves left, Leaves collected) : this()
+        {
+            _count = count;
+            Left = _initLeft = left;
+            Collected = _initCollected = collected;
+        }
+
+        public int Index => _i - 1;
+
+        public bool Next() => BranchPatternMatcher.Next(ref _i, _count);
+
+        public Leaves Left { get; private set; }
+        public Leaves Collected { get; private set; }
+
+        public bool Match(LeafPatternMatcher matcher, string name, ValueKind kind) =>
+            Fold(matcher.Match(Left, Collected, name, kind));
+
+        public bool Match(Pattern pattern) =>
+            Fold(pattern.Match(Left, Collected));
+
+        public bool Fold(MatchResult match)
+        {
+            if (!match)
+            {
+                _result = new MatchResult(false, _initLeft, _initCollected);
+                return LastMatched = false;
+            }
+            (_, Left, Collected) = match;
+            return LastMatched = true;
+        }
+
+        public bool LastMatched { get; private set; }
+
+        public MatchResult Result => _result ?? new MatchResult(true, Left, Collected);
+    }
+
+    struct EitherMatcher : IBranchPatternMatcher
+    {
+        readonly int _count;
+        int _i;
+        MatchResult _match;
+
+        public EitherMatcher(int count, Leaves left, Leaves collected) : this()
+        {
+            _count = count;
+            (Left, Collected) = (left, collected);
+            _match = new MatchResult(false, left, collected);
+        }
+
+        public int Index => _i - 1;
+
+        public bool Next() => BranchPatternMatcher.Next(ref _i, _count);
+
+        public Leaves Left { get; }
+        public Leaves Collected { get; }
+
+        public bool Match(LeafPatternMatcher matcher, string name, ValueKind kind) =>
+            Fold(matcher.Match(Left, Collected, name, kind));
+
+        public bool Match(Pattern pattern) =>
+            Fold(pattern.Match(Left, Collected));
+
+        public bool Fold(MatchResult match)
+        {
+            if (match is (true, var left, var collected) && (!_match || left.Count < _match.Left.Count))
+                _match = new MatchResult(true, left, collected);
+            return true;
+        }
+
+        public bool LastMatched => true;
+
+        public MatchResult Result => _match;
+    }
+
+    struct OptionalMatcher : IBranchPatternMatcher
+    {
+        readonly int _count;
+        int _i;
+
+        public OptionalMatcher(int count, Leaves left, Leaves collected) : this() =>
+            (_count, Left, Collected) = (count, left, collected);
+
+        public int Index => _i - 1;
+
+        public bool Next() => BranchPatternMatcher.Next(ref _i, _count);
+
+        public Leaves Left { get; private set; }
+        public Leaves Collected { get; private set; }
+
+        public bool Match(LeafPatternMatcher matcher, string name, ValueKind kind) =>
+            Fold(matcher.Match(Left, Collected, name, kind));
+
+        public bool Match(Pattern pattern) =>
+            Fold(pattern.Match(Left, Collected));
+
+        public bool Fold(MatchResult match)
+        {
+            (_, Left, Collected) = match;
+            return true;
+        }
+
+        public bool LastMatched => true;
+
+        public MatchResult Result => new(true, Left, Collected);
+    }
+
+    struct OneOrMoreMatcher : IBranchPatternMatcher
+    {
+        readonly Leaves _initLeft, _initCollected;
+        int _times;
+        Leaves? _lastLeft;
+
+        public OneOrMoreMatcher(int count, Leaves left, Leaves collected) : this()
+        {
+            Left = _initLeft = left;
+            Collected = _initCollected = collected;
+        }
+
+        public int Index => 0;
+        public bool Next() => true;
+
+        public Leaves Left { get; private set; }
+        public Leaves Collected { get; private set; }
+
+        public bool Match(LeafPatternMatcher matcher, string name, ValueKind kind) =>
+            Fold(matcher.Match(Left, Collected, name, kind));
+
+        public bool Match(Pattern pattern) =>
+            Fold(pattern.Match(Left, Collected));
+
+        public bool Fold(MatchResult match)
+        {
+            bool matched;
+            (matched, Left, Collected) = match;
+            _times += matched ? 1 : 0;
+            if (_lastLeft != null && _lastLeft.Equals(Left))
+                return LastMatched = false;
+            _lastLeft = Left;
+            return LastMatched = true;
+        }
+
+        public bool LastMatched { get; private set; }
+
+        public MatchResult Result =>
+            _times >= 1 ? new MatchResult(true, Left, Collected)
+                        : new MatchResult(false, _initLeft, _initCollected);
+    }
 
     static class PatternMatcher
     {
-        public static MatchResult Match(this Pattern pattern, ReadOnlyList<LeafPattern> left)
+        public static MatchResult Match(this Pattern pattern, Leaves left)
         {
-            return pattern.Match(left, new ReadOnlyList<LeafPattern>());
+            return pattern.Match(left, new Leaves());
         }
 
-        static MatchResult Match(this Pattern pattern,
-                                 ReadOnlyList<LeafPattern> left,
-                                 ReadOnlyList<LeafPattern> collected)
+        public static MatchResult Match(this Pattern pattern, Leaves left, Leaves collected)
         {
             switch (pattern)
             {
-                case Required required:
-                {
-                    var l = left;
-                    var c = collected;
-                    foreach (var child in required.Children)
-                    {
-                        bool matched;
-                        (matched, l, c) = child.Match(l, c);
-                        if (!matched)
-                            return new MatchResult(false, left, collected);
-                    }
-                    return new MatchResult(true, l, c);
-                }
-                case Either either:
+                case Required  { Children: { Count: var count } children }: return MatchBranch(children, new RequiredMatcher(count, left, collected));
+                case Either    { Children: { Count: var count } children }: return MatchBranch(children, new EitherMatcher(count, left, collected));
+                case Optional  { Children: { Count: var count } children }: return MatchBranch(children, new OptionalMatcher(count, left, collected));
+                case OneOrMore { Children: {} children }: return MatchBranch(children, new OneOrMoreMatcher(1, left, collected));
+                case LeafPattern leaf:
                 {
-                    var match = new MatchResult(false, left, collected);
-                    foreach (var child in either.Children)
+                    var matcher = leaf switch
                     {
-                        if (child.Match(left, collected) is (true, var l, var c)
-                            && (!match || l.Count < match.Left.Count))
-                        {
-                            match = new MatchResult(true, l, c);
-                        }
-                    }
-                    return match;
-                }
-                case Optional optional:
-                {
-                    var l = left;
-                    var c = collected;
-                    foreach (var child in optional.Children)
-                        (_, l, c) = child.Match(l, c);
-                    return new MatchResult(true, l, c);
+                        Command  => CommandMatcher,
+                        Argument => ArgumentMatcher,
+                        Option   => OptionMatcher,
+                        _ => throw new NotSupportedException()
+                    };
+
+                    return matcher.Match(left, collected, leaf.Name, leaf.Value.Kind);
                 }
-                case OneOrMore oneOrMore:
+                default:
+                    throw new ArgumentException(nameof(pattern));
+            }
+
+            static MatchResult MatchBranch<T>(IList<Pattern> children, T matcher) where T : IBranchPatternMatcher
+            {
+                while (matcher.Next())
                 {
-                    Debug.Assert(oneOrMore.Children.Count == 1);
-                    var l = left;
-                    var c = collected;
-                    ReadOnlyList<LeafPattern>? l_ = null;
-                    var matched = true;
-                    var times = 0;
-                    while (matched)
-                    {
-                        // could it be that something didn't match but changed l or c?
-                        (matched, l, c) = oneOrMore.Children[0].Match(l, c);
-                        times += matched ? 1 : 0;
-                        if (l_ != null && l_.Equals(l))
-                            break;
-                        l_ = l;
-                    }
-                    if (times >= 1)
-                    {
-                        return new MatchResult(true, l, c);
-                    }
-                    return new MatchResult(false, left, collected);
+                    if (!matcher.Match(children[matcher.Index]))
+                        break;
                 }
-                case Command command:
+                return matcher.Result;
+            }
+        }
+
+        public static MatchResult MatchLeaf(Leaves left, Leaves collected,
+                                            string name, ValueKind kind,
+                                            int index, LeafPattern? match)
+        {
+            if (match == null)
+            {
+                return new MatchResult(false, left, collected);
+            }
+            var left_ = left.RemoveAt(index);
+            if (kind is ValueKind.StringList or ValueKind.Integer)
+            {
+                var sameNames = collected.Where(a => a.Name == name).ToList();
+                if (sameNames.Count == 0)
                 {
-                    for (var i = 0; i < left.Count; i++)
-                    {
-                        if (left[i] is Argument { Value: { } value })
-                        {
-                            if (value.ToString() == command.Name)
-                                return MatchLeaf(command, i, new Command(command.Name, true));
-                            break;
-                        }
-                    }
-                    return new MatchResult(false, left, collected);
+                    match.Value = kind == ValueKind.Integer ? 1
+                                : match.Value.TryAsString(out var s) ? StringList.Empty.Push(s)
+                                : match.Value;
                 }
-                case Argument argument:
+                else
                 {
-                    for (var i = 0; i < left.Count; i++)
-                    {
-                        if (left[i] is Argument { Value: var value })
-                            return MatchLeaf(argument, i, new Argument(argument.Name) { Value = value });
-                    }
-                    return new MatchResult(false, left, collected);
+                    var sameName = sameNames[0];
+                    sameName.Value = sameName.Value.TryAsInteger(out var n)
+                                   ? n + 1
+                                   : ((StringList)sameName.Value).Push((string)match.Value);
+
+                    return new MatchResult(true, left_, collected);
                 }
-                case Option option:
+            }
+            return new MatchResult(true, left_, collected.Append(match));
+        }
+
+        public static readonly LeafPatternMatcher CommandMatcher  = MatchCommand;
+        public static readonly LeafPatternMatcher ArgumentMatcher = MatchArgument;
+        public static readonly LeafPatternMatcher OptionMatcher   = MatchOption;
+
+        public static (int, LeafPattern) MatchCommand(Leaves left, string command)
+        {
+            for (var i = 0; i < left.Count; i++)
+            {
+                if (left[i] is Argument { Value: var value })
                 {
-                    for (var i = 0; i < left.Count; i++)
-                    {
-                        if (left[i].Name == option.Name)
-                            return MatchLeaf(option, i, left[i]);
-                    }
-                    return new MatchResult(false, left, collected);
+                    if ((string)value == command)
+                        return (i, new Command(command, true));
+                    break;
                 }
-                default:
-                    throw new ArgumentException(nameof(pattern));
             }
+            return default;
+        }
 
-            MatchResult MatchLeaf(LeafPattern leaf, int index, LeafPattern match)
+        public static (int, LeafPattern) MatchArgument(Leaves left, string name)
+        {
+            for (var i = 0; i < left.Count; i++)
             {
-                var left_ = left.RemoveAt(index);
-                if (leaf is { Value: { Kind: ValueKind.StringList or ValueKind.Integer } })
-                {
-                    var sameNames = collected.Where(a => a.Name == leaf.Name).ToList();
-                    if (sameNames.Count == 0)
-                    {
-                        match.Value = leaf.Value.IsInteger ? 1
-                                    : match.Value.TryAsString(out var s) ? StringList.Empty.Push(s)
-                                    : match.Value;
-                    }
-                    else
-                    {
-                        var sameName = sameNames[0];
-                        sameName.Value = sameName.Value.TryAsInteger(out var n)
-                                       ? n + 1
-                                       : ((StringList)sameName.Value).Push((string)match.Value);
+                if (left[i] is Argument { Value: var value })
+                    return (i, new Argument(name) { Value = value });
+            }
+            return default;
+        }
 
-                        return new MatchResult(true, left_, collected);
-                    }
-                }
-                return new MatchResult(true, left_, collected.Append(match));
+        public static (int, LeafPattern) MatchOption(Leaves left, string name)
+        {
+            for (var i = 0; i < left.Count; i++)
+            {
+                if (left[i].Name == name)
+                    return (i, (Option)left[i]);
             }
+            return default;
         }
     }
 }
diff --git a/src/DocoptNet/ValueObject.cs b/src/DocoptNet/ValueObject.cs
index 264fbc05..bdc97f80 100644
--- a/src/DocoptNet/ValueObject.cs
+++ b/src/DocoptNet/ValueObject.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 namespace DocoptNet
 {
     using System;
diff --git a/tests/DocoptNet.Tests/CodeGeneration/AdditionalTextString.cs b/tests/DocoptNet.Tests/CodeGeneration/AdditionalTextString.cs
new file mode 100644
index 00000000..6fab427a
--- /dev/null
+++ b/tests/DocoptNet.Tests/CodeGeneration/AdditionalTextString.cs
@@ -0,0 +1,24 @@
+#nullable enable
+
+namespace DocoptNet.Tests.CodeGeneration
+{
+    using System.Threading;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.Text;
+
+    sealed class AdditionalTextString : AdditionalText
+    {
+        readonly SourceText _text;
+
+        public AdditionalTextString(string path, string text)
+        {
+            Path = path;
+            _text = SourceText.From(text);
+        }
+
+        public override SourceText? GetText(CancellationToken cancellationToken = default) =>
+            _text;
+
+        public override string Path { get; }
+    }
+}
diff --git a/tests/DocoptNet.Tests/CodeGeneration/AnalyzerConfigOptions.cs b/tests/DocoptNet.Tests/CodeGeneration/AnalyzerConfigOptions.cs
new file mode 100644
index 00000000..fcc5df69
--- /dev/null
+++ b/tests/DocoptNet.Tests/CodeGeneration/AnalyzerConfigOptions.cs
@@ -0,0 +1,24 @@
+#nullable enable
+
+namespace DocoptNet.Tests.CodeGeneration
+{
+    using System.Collections.Generic;
+    using System.Collections.Immutable;
+    using System.Diagnostics.CodeAnalysis;
+
+    sealed class AnalyzerConfigOptions : Microsoft.CodeAnalysis.Diagnostics.AnalyzerConfigOptions
+    {
+        public static readonly AnalyzerConfigOptions Empty = new(ImmutableDictionary<string, string>.Empty);
+
+        readonly ImmutableDictionary<string, string> _options;
+
+        public AnalyzerConfigOptions(params KeyValuePair<string, string>[] options) :
+            this(ImmutableDictionary.CreateRange(options)) {}
+
+        public AnalyzerConfigOptions(ImmutableDictionary<string, string> options) =>
+            _options = options;
+
+        public override bool TryGetValue(string key, [NotNullWhen(true)] out string? value) =>
+            _options.TryGetValue(key, out value);
+    }
+}
diff --git a/tests/DocoptNet.Tests/CodeGeneration/AnalyzerConfigOptionsProvider.cs b/tests/DocoptNet.Tests/CodeGeneration/AnalyzerConfigOptionsProvider.cs
new file mode 100644
index 00000000..09141971
--- /dev/null
+++ b/tests/DocoptNet.Tests/CodeGeneration/AnalyzerConfigOptionsProvider.cs
@@ -0,0 +1,29 @@
+#nullable enable
+
+namespace DocoptNet.Tests.CodeGeneration
+{
+    using System.Collections.Generic;
+    using System.Collections.Immutable;
+    using Microsoft.CodeAnalysis;
+    using RsAnalyzerConfigOptions = Microsoft.CodeAnalysis.Diagnostics.AnalyzerConfigOptions;
+
+    sealed class AnalyzerConfigOptionsProvider :
+        Microsoft.CodeAnalysis.Diagnostics.AnalyzerConfigOptionsProvider
+    {
+        readonly ImmutableDictionary<AdditionalText, RsAnalyzerConfigOptions> _additionalTextOptions;
+
+        public AnalyzerConfigOptionsProvider(params KeyValuePair<AdditionalText, RsAnalyzerConfigOptions>[] options) :
+            this(ImmutableDictionary.CreateRange(options)) {}
+
+        public AnalyzerConfigOptionsProvider(ImmutableDictionary<AdditionalText, RsAnalyzerConfigOptions> optionsByAdditionalText) =>
+            _additionalTextOptions = optionsByAdditionalText;
+
+        public override AnalyzerConfigOptions GetOptions(SyntaxTree tree) =>
+            AnalyzerConfigOptions.Empty;
+
+        public override RsAnalyzerConfigOptions GetOptions(AdditionalText textFile) =>
+            _additionalTextOptions.TryGetValue(textFile, out var options) ? options : AnalyzerConfigOptions.Empty;
+
+        public override RsAnalyzerConfigOptions GlobalOptions => AnalyzerConfigOptions.Empty;
+    }
+}
diff --git a/tests/DocoptNet.Tests/CodeGeneration/LanguageAgnosticTests.cs b/tests/DocoptNet.Tests/CodeGeneration/LanguageAgnosticTests.cs
new file mode 100644
index 00000000..f37b6540
--- /dev/null
+++ b/tests/DocoptNet.Tests/CodeGeneration/LanguageAgnosticTests.cs
@@ -0,0 +1,109 @@
+#nullable enable
+
+namespace DocoptNet.Tests.CodeGeneration
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Globalization;
+    using System.Reflection;
+    using System.Text.RegularExpressions;
+    using DocoptNet.CodeGeneration;
+    using Microsoft.CodeAnalysis.Text;
+    using Newtonsoft.Json;
+    using NUnit.Framework;
+
+    [TestFixture]
+    public class LanguageAgnosticTests
+    {
+        [Test]
+        [TestCaseSource(typeof(Tests.LanguageAgnosticTests),
+                        nameof(Tests.LanguageAgnosticTests.Docopt),
+                        new object[] { "testcases.docopt" })]
+        public void Test(string doc, string cmdLine, string expected)
+        {
+            const string main = @"
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using DocoptNet.Generated;
+using Newtonsoft.Json;
+
+public partial class Program
+{
+    readonly IDictionary<string, Value> _args;
+
+    public Program(IList<string> argv)
+    {
+        var arguments = ProgramArguments.Apply(argv, help: true, version: null, optionsFirst: false);
+        var dict = new Dictionary<string, object>();
+        foreach (var (name, value) in arguments)
+        {
+            if (value is StringList items)
+            {
+                var l = new ArrayList();
+                foreach (var item in items)
+                    l.Add(item);
+                dict[name] = l;
+            }
+            else
+                dict[name] = value;
+        }
+        Json = JsonConvert.SerializeObject(dict);
+    }
+
+    public string Json { get; }
+}
+";
+            Assembly assembly;
+
+            try
+            {
+                assembly = SourceGeneratorTests.GenerateProgram(doc, main);
+            }
+            catch (Exception e)
+            {
+                static int ParseInt(string s) => int.Parse(s, NumberStyles.None, CultureInfo.InvariantCulture);
+                var (errorLineNumber, _) =
+                    e is AssertionException
+                    && Regex.Match(e.Message, @"\(([1-9][0-9]*),([1-9][0-9]*)\):\s*error\b") is { Success: true, Groups: {} groups }
+                    ? (ParseInt(groups[1].Value), ParseInt(groups[2].Value))
+                    : default;
+                var sourceText = SourceGenerator.Generate(null, "Program", SourceText.From(doc));
+                foreach (var line in sourceText.Lines)
+                {
+                    var lineNumber = line.LineNumber + 1; // convert zero-base to one-based line number
+                    Console.WriteLine($"{(lineNumber == errorLineNumber ? '!' : ' ')}{lineNumber,5}: {line}");
+                }
+
+                throw;
+            }
+            var type = assembly.GetType("Program")!;
+            Assert.That(type, Is.Not.Null);
+
+            string actual;
+            try
+            {
+                var program = Activator.CreateInstance(type, (IList<string>)cmdLine.Split(' ', StringSplitOptions.RemoveEmptyEntries))!;
+                Assert.That(program, Is.Not.Null);
+                actual = (string)((dynamic)program).Json;
+            }
+            catch (TargetInvocationException e) when (e.GetBaseException().GetType().Name.StartsWith("Docopt", StringComparison.OrdinalIgnoreCase))
+            {
+                actual = "\"user-error\"";
+            }
+
+            if (expected.StartsWith("{"))
+            {
+                var expectedDict = JsonConvert.DeserializeObject<Dictionary<string, object>>(expected);
+                var actualDict = JsonConvert.DeserializeObject<Dictionary<string, object>>(actual);
+                Assert.That(actualDict, Is.EquivalentTo(expectedDict));
+            }
+            else
+            {
+                var expected1 = JsonConvert.DeserializeObject(expected)!.ToString();
+                var actual1 = JsonConvert.DeserializeObject(actual)!.ToString();
+                Assert.AreEqual(expected1, actual1);
+            }
+        }
+    }
+}
diff --git a/tests/DocoptNet.Tests/CodeGeneration/SourceGeneratorTests.cs b/tests/DocoptNet.Tests/CodeGeneration/SourceGeneratorTests.cs
new file mode 100644
index 00000000..ab61960e
--- /dev/null
+++ b/tests/DocoptNet.Tests/CodeGeneration/SourceGeneratorTests.cs
@@ -0,0 +1,234 @@
+#nullable enable
+
+namespace DocoptNet.Tests.CodeGeneration
+{
+    using System;
+    using System.Collections;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Linq;
+    using System.Reflection;
+    using System.Runtime.Loader;
+    using System.Threading;
+    using DocoptNet.CodeGeneration;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.CSharp;
+    using Microsoft.CodeAnalysis.Text;
+    using NUnit.Framework;
+    using RsAnalyzerConfigOptions = Microsoft.CodeAnalysis.Diagnostics.AnalyzerConfigOptions;
+
+    [TestFixture]
+    public class SourceGeneratorTests
+    {
+        const string NavalFateUsage = @"
+Naval Fate.
+
+    Usage:
+      naval_fate.exe ship new <name>...
+      naval_fate.exe ship <name> move <x> <y> [--speed=<kn>]
+      naval_fate.exe ship shoot <x> <y>
+      naval_fate.exe mine (set|remove) <x> <y> [--moored | --drifting]
+      naval_fate.exe (-h | --help)
+      naval_fate.exe --version
+
+    Options:
+      -h --help     Show this screen.
+      --version     Show version.
+      --speed=<kn>  Speed in knots [default: 10].
+      --moored      Moored (anchored) mine.
+      --drifting    Drifting mine.
+";
+
+        [Test]
+        public void Generate()
+        {
+            var source = SourceGenerator.Generate("NavalFate", "Program", SourceText.From(NavalFateUsage)).ToString();
+            Assert.That(source, Is.Not.Empty);
+        }
+
+        Program? _generatedProgram;
+
+        Program GeneratedProgram
+        {
+            get { return _generatedProgram ?? throw new InvalidOperationException(); }
+            set { _generatedProgram = value; }
+        }
+
+        [OneTimeSetUp]
+        public void SetUp()
+        {
+            _generatedProgram = GenerateProgram(NavalFateUsage);
+        }
+
+        [Test]
+        public void Generate_via_driver()
+        {
+            var args = GeneratedProgram.Run(args => new NavalFateArgs(args), "ship", "new", "foo", "bar");
+
+            Assert.That(args.Count, Is.EqualTo(15));
+
+            Assert.That(args.CmdShip, Is.True);
+            Assert.That(args.CmdNew, Is.True);
+
+            var name = args.ArgName!.Cast<string>().ToList();
+            Assert.That(name, Is.Not.Null);
+            Assert.That(name.Count, Is.EqualTo(2));
+            Assert.That(name[0], Is.EqualTo("foo"));
+            Assert.That(name[1], Is.EqualTo("bar"));
+
+            Assert.That(args.CmdMove, Is.False);
+            Assert.That(args.ArgX, Is.Null);
+            Assert.That(args.ArgY, Is.Null);
+            Assert.That(args.OptSpeed, Is.EqualTo("10"));
+            Assert.That(args.CmdShoot, Is.False);
+            Assert.That(args.CmdMine, Is.False);
+            Assert.That(args.CmdSet, Is.False);
+            Assert.That(args.CmdRemove, Is.False);
+            Assert.That(args.OptMoored, Is.False);
+            Assert.That(args.OptDrifting, Is.False);
+            Assert.That(args.OptHelp, Is.False);
+            Assert.That(args.OptVersion, Is.False);
+        }
+
+        sealed record DocoptOptions(bool Help = true,
+                                    object? Version = null,
+                                    bool OptionsFirst = false,
+                                    bool Exit = false)
+        {
+            public static readonly DocoptOptions Default = new();
+        }
+
+        class ProgramArgs
+        {
+            readonly IDictionary _args;
+
+            public ProgramArgs(IDictionary args) =>
+                _args = args ?? throw new ArgumentNullException("args");
+
+            public int Count => _args.Count;
+
+            public T Get<T>(string key, Func<object?, T> selector) =>
+                _args.Contains(key)
+                ? selector(_args[key])
+                : throw new KeyNotFoundException("Key was not present in the dictionary: " + key);
+        }
+
+        sealed class NavalFateArgs : ProgramArgs
+        {
+            public NavalFateArgs(IDictionary args) : base(args) {}
+
+            public bool?        CmdShip        => Get("ship", v => (bool?)v);
+            public bool?        CmdNew         => Get("new", v => (bool?)v);
+            public IEnumerable? ArgName        => Get("<name>", v => (IEnumerable?)v);
+            public bool?        CmdMove        => Get("move", v => (bool?)v);
+            public int?         ArgX           => Get("<x>", v => (int?)v);
+            public int?         ArgY           => Get("<y>", v => (int?)v);
+            public string?      OptSpeed       => Get("--speed", v => (string?)v);
+            public bool?        CmdShoot       => Get("shoot", v => (bool?)v);
+            public bool?        CmdMine        => Get("mine", v => (bool?)v);
+            public bool?        CmdSet         => Get("set", v => (bool?)v);
+            public bool?        CmdRemove      => Get("remove", v => (bool?)v);
+            public bool?        OptMoored      => Get("--moored", v => (bool?)v);
+            public bool?        OptDrifting    => Get("--drifting", v => (bool?)v);
+            public bool?        OptHelp        => Get("--help", v => (bool?)v);
+            public bool?        OptVersion     => Get("--version", v => (bool?)v);
+        }
+
+        sealed class Program
+        {
+            readonly Type _type;
+
+            public Program(Type type) => _type = type ?? throw new ArgumentNullException(nameof(type));
+
+            public ProgramArgs Run(params string[] argv) =>
+                Run(DocoptOptions.Default, argv);
+
+            public ProgramArgs Run(DocoptOptions options, params string[] argv) =>
+                Run(options, args => new ProgramArgs(args), argv);
+
+            public T Run<T>(Func<IDictionary, T> selector, params string[] argv) =>
+                Run<T>(DocoptOptions.Default, selector, argv);
+
+            public T Run<T>(DocoptOptions options, Func<IDictionary, T> selector, params string[] argv)
+            {
+                const string applyMethodName = "Apply";
+                var method = _type.GetMethod(applyMethodName, BindingFlags.Public | BindingFlags.Static);
+                if (method == null)
+                    throw new MissingMethodException(_type.Name, applyMethodName);
+                var args = (IEnumerable<KeyValuePair<string, object?>>)
+                    method.Invoke(null, new[]
+                    {
+                        argv,
+                        options.Help, options.Version,
+                        options.OptionsFirst
+                    })!;
+                Assert.That(args, Is.Not.Null);
+                return selector(args.ToDictionary(e => e.Key, e => e.Value));
+            }
+        }
+
+        static Program GenerateProgram(string usage)
+        {
+            const string main = @"
+using System.Collections.Generic;
+using DocoptNet.Generated;
+
+public partial class " + nameof(Program) + @"Arguments { }
+
+namespace DocoptNet.Generated
+{
+    public partial class StringList {}
+}
+";
+
+            var assembly = GenerateProgram(usage, main);
+            return new Program(assembly.GetType(nameof(Program) + "Arguments")!);
+        }
+
+        static int _assemblyUniqueCounter;
+
+        internal static Assembly GenerateProgram(string usage, string source)
+        {
+            var references =
+                from asm in AppDomain.CurrentDomain.GetAssemblies()
+                where !asm.IsDynamic && !string.IsNullOrWhiteSpace(asm.Location)
+                select MetadataReference.CreateFromFile(asm.Location);
+
+            var compilation =
+                CSharpCompilation.Create(FormattableString.Invariant($"test{Interlocked.Increment(ref _assemblyUniqueCounter)}"),
+                                         new[] { CSharpSyntaxTree.ParseText(source) },
+                                         references,
+                                         new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
+
+            ISourceGenerator generator = new SourceGenerator();
+
+            AdditionalText additionalText = new AdditionalTextString("Program.docopt.txt", usage);
+
+            RsAnalyzerConfigOptions options =
+                new AnalyzerConfigOptions(
+                    KeyValuePair.Create("build_metadata.AdditionalFiles.SourceItemType", "Docopt"));
+
+            var driver =
+                CSharpGeneratorDriver.Create(new[] { generator },
+                                             new[] { additionalText },
+                                             optionsProvider: new AnalyzerConfigOptionsProvider(KeyValuePair.Create(additionalText, options)));
+
+            driver.RunGeneratorsAndUpdateCompilation(compilation,
+                                                     out var outputCompilation,
+                                                     out var generateDiagnostics);
+
+            Assert.False(generateDiagnostics.Any(d => d.Severity == DiagnosticSeverity.Error),
+                         "Failed: " + generateDiagnostics.FirstOrDefault()?.GetMessage());
+
+            using var ms = new MemoryStream();
+            var emitResult = outputCompilation.Emit(ms);
+
+            Assert.False(emitResult.Diagnostics.Any(d => d.Severity == DiagnosticSeverity.Error),
+                         "Failed: " + emitResult.Diagnostics.FirstOrDefault());
+
+            ms.Position = 0;
+
+            return AssemblyLoadContext.Default.LoadFromStream(ms);
+        }
+    }
+}
diff --git a/tests/DocoptNet.Tests/DocoptNet.Tests.csproj b/tests/DocoptNet.Tests/DocoptNet.Tests.csproj
index 6da2def2..0efbd868 100644
--- a/tests/DocoptNet.Tests/DocoptNet.Tests.csproj
+++ b/tests/DocoptNet.Tests/DocoptNet.Tests.csproj
@@ -8,6 +8,10 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Remove="CodeGeneration\*.cs" Condition="'$(TargetFramework)' != 'net5.0'" />
+  </ItemGroup>
+
   <ItemGroup>
     <None Include="..\LanguageAgnosticTests\testcases.docopt" Link="testcases.docopt">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
@@ -15,6 +19,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="nunit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
@@ -23,6 +28,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\..\src\DocoptNet.CodeGeneration\DocoptNet.CodeGeneration.csproj" />
     <ProjectReference Include="..\..\src\DocoptNet\DocoptNet.csproj" />
   </ItemGroup>
 
diff --git a/tests/DocoptNet.Tests/GenerateCodeHelperTest.cs b/tests/DocoptNet.Tests/GenerateCodeHelperTest.cs
index fccd236f..0a771feb 100644
--- a/tests/DocoptNet.Tests/GenerateCodeHelperTest.cs
+++ b/tests/DocoptNet.Tests/GenerateCodeHelperTest.cs
@@ -42,5 +42,16 @@ public void ConvertToPascalCase_all_uppercase_letters(char sep)
             var actual = GenerateCodeHelper.ConvertToPascalCase(input);
             Assert.AreEqual(expected, actual);
         }
+
+        [TestCase("foo-bar", "FooBar")]
+        [TestCase("foo bar", "FooBar")]
+        [TestCase("foo+bar", "FooPlusBar")]
+        [TestCase("foo/bar", "FooSlashBar")]
+        [TestCase("-", "Minus")]
+        public void ConvertDashesToCamelCase(string input, string expected)
+        {
+            var actual = GenerateCodeHelper.ConvertToPascalCase(input);
+            Assert.That(actual, Is.EqualTo(expected));
+        }
     }
 }
diff --git a/tests/DocoptNet.Tests/LanguageAgnosticTests.cs b/tests/DocoptNet.Tests/LanguageAgnosticTests.cs
index 316a5def..4e80efa3 100644
--- a/tests/DocoptNet.Tests/LanguageAgnosticTests.cs
+++ b/tests/DocoptNet.Tests/LanguageAgnosticTests.cs
@@ -51,7 +51,7 @@ public void Test(string doc, string cmdLine, string expected)
         /// <seealso cref="TestContext.WorkDirectory"/>.
         /// </remarks>
 
-        static IEnumerable<TestCaseData> Docopt(string path)
+        public static IEnumerable<TestCaseData> Docopt(string path)
         {
             // quick and dirty "*.docopt" to test cases conversion