feat: blocks create scopes

heir-lang · Dec 17, 2024 · 494df6b · 494df6b
1 parent 473dde5
commit 494df6b
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Showing 4 changed files with 29 additions and 6 deletions.
diff --git a/Heir/BytecodeGenerator.cs b/Heir/BytecodeGenerator.cs
@@ -20,11 +20,16 @@ public List<Instruction> VisitSyntaxTree(SyntaxTree syntaxTree) =>
             .ToList();
 
         // TODO: create scope
-        public List<Instruction> VisitBlock(Block block) => GenerateStatementsBytecode(block.Statements);
+        public List<Instruction> VisitBlock(Block block) =>
+            GenerateStatementsBytecode(block.Statements)
+            .Prepend(new Instruction(block, OpCode.BEGINSCOPE))
+            .Append(new Instruction(block, OpCode.ENDSCOPE))
+            .ToList();
+
         public List<Instruction> VisitVariableDeclaration(VariableDeclaration variableDeclaration) =>
             new List<Instruction>([new Instruction(variableDeclaration.Name, OpCode.PUSH, variableDeclaration.Name.Token.Text)])
             .Concat(variableDeclaration.Initializer != null ? GenerateBytecode(variableDeclaration.Initializer) : [])
-            .Append(new Instruction(variableDeclaration, OpCode.STORE))
+            .Append(new Instruction(variableDeclaration, OpCode.STORE, false))
             .ToList();
 
         public List<Instruction> VisitExpressionStatement(ExpressionStatement expressionStatement) => GenerateBytecode(expressionStatement.Expression);

diff --git a/Heir/CodeGeneration/OpCode.cs b/Heir/CodeGeneration/OpCode.cs
@@ -2,6 +2,9 @@
 {
     public enum OpCode : byte
     {
+        BEGINSCOPE,
+        ENDSCOPE,
+
         PUSH,
         PUSHNONE,
         POP,

diff --git a/Heir/VirtualMachine.cs b/Heir/VirtualMachine.cs
@@ -15,17 +15,19 @@ public sealed class VirtualMachine
     {
         public DiagnosticBag Diagnostics { get; }
         public Scope GlobalScope { get; }
-        public Scope Scope { get; }
+        public Scope Scope { get; private set; }
 
-        private readonly Stack<StackFrame> _stack = new();
+        private readonly Stack<StackFrame> _stack = [];
         private readonly Bytecode _bytecode;
+        private Scope _enclosingScope;
         private int _pointer = 0;
 
         public VirtualMachine(Bytecode bytecode, Scope? scope = null)
         {
             Diagnostics = bytecode.Diagnostics;
             GlobalScope = new();
             Scope = scope ?? GlobalScope;
+            _enclosingScope = Scope;
             _bytecode = bytecode;
         }
 
@@ -62,6 +64,17 @@ public VirtualMachine(Bytecode bytecode, Scope? scope = null)
                 case OpCode.RETURN:
                     return _stack.Pop();
 
+                case OpCode.BEGINSCOPE:
+                    _enclosingScope = Scope;
+                    Scope = new(_enclosingScope);
+                    Advance();
+                    break;
+                case OpCode.ENDSCOPE:
+                    Scope = _enclosingScope;
+                    _enclosingScope = Scope.Enclosing ?? Scope;
+                    Advance();
+                    break;
+
                 case OpCode.PUSH:
                 case OpCode.PUSHNONE:
                     _stack.Push(CreateStackFrameFromInstruction());
@@ -123,7 +136,9 @@ public VirtualMachine(Bytecode bytecode, Scope? scope = null)
                         else
                             Scope.Define(name, initializer.Value);
 
-                        _stack.Push(initializer);
+                        if (instruction.Operand as bool? ?? true)
+                            _stack.Push(initializer);
+
                         Advance();
                         break;
                     }

diff --git a/Test.heir b/Test.heir
@@ -1 +1 @@
-1 + 2
+let x = 1;