Convert difficulty to Option[int] and check range

src/cli.nim

@@ -1,4 +1,4 @@
-import std/[os, parseutils, strformat, strutils, terminal]
+import std/[options, os, parseutils, strformat, strutils, terminal]
 import pkg/supersnappy
 import patched_libs/parseopt3
 
@@ -48,7 +48,7 @@ type
       exerciseCreate*: string
       offlineCreate*: bool
       author*: string
-      difficulty*: int
+      difficulty*: Option[int]
     of actFmt:
       # We can't name these fields `exercise`, `update`, and `yes` because we
       # use those names in `actSync`, and Nim doesn't yet support duplicate

src/create/create.nim

@@ -1,4 +1,4 @@
-import std/[os, strformat]
+import std/[options, os, strformat]
 import ".."/[cli, helpers, sync/sync, types_track_config]
 import "."/[approaches, articles, exercises]
 
@@ -13,7 +13,7 @@ proc create*(conf: Conf) =
         let msg = &"Both --approach and --article were provided. Please specify only one."
         stderr.writeLine msg
         quit QuitFailure
-      if conf.action.difficulty > 0:
+      if conf.action.difficulty.isSome:
         let msg = "The difficulty argument is not supported for approaches"
         stderr.writeLine msg
         quit QuitFailure
@@ -40,7 +40,7 @@ proc create*(conf: Conf) =
         let msg = "Please specify an exercise to create an article for, using --exercise <slug>"
         stderr.writeLine msg
         quit QuitFailure
-      if conf.action.difficulty > 0:
+      if conf.action.difficulty.isSome:
         let msg = "The difficulty argument is not supported for approaches"
         stderr.writeLine msg
         quit QuitFailure
@@ -63,8 +63,18 @@ proc create*(conf: Conf) =
 
       createArticle(Slug(conf.action.articleSlug), userExercise, exerciseDir)
     elif conf.action.conceptExerciseSlug.len > 0:
+      if conf.action.difficulty.isSome and conf.action.difficulty.get notin 1..10:
+        let msg = "The difficulty must be an integer between 1 and 10"
+        stderr.writeLine msg
+        quit QuitFailure
+
       createConceptExercise(conf)
     elif conf.action.practiceExerciseSlug.len > 0:
+      if conf.action.difficulty.isSome and conf.action.difficulty.get notin 1..10:
+        let msg = "The difficulty must be an integer between 1 and 10"
+        stderr.writeLine msg
+        quit QuitFailure
+
       createPracticeExercise(conf)
     else:
       let msg = "Please specify `--practice-exercise <slug>`, `--concept-exercise <slug>`, " &