compiler/Compiler/Generator.cs

@@ -23,16 +23,16 @@ public sealed class Generator(List<NodeDefinition> nodes)
 
         foreach (var node in nodes.OfType<NodeDefinitionFunc>())
         {
-            var parameters = node.Parameters.Select(x => $"{CType(x.Type)} {x.Name.Ident}");
+            var parameters = node.Parameters.Select(x => CType(x.Type, x.Name.Ident));
-            writer.WriteLine($"{CType(node.ReturnType)} {node.Name.Ident}({string.Join(", ", parameters)});");
+            writer.WriteLine($"{CType(node.ReturnType, node.Name.Ident)}({string.Join(", ", parameters)});");
         }
 
         writer.WriteLine();
 
         foreach (var node in nodes.OfType<NodeDefinitionFunc>())
         {
-            var parameters = node.Parameters.Select(x => $"{CType(x.Type)} {x.Name.Ident}");
+            var parameters = node.Parameters.Select(x => CType(x.Type, x.Name.Ident));
-            writer.WriteLine($"{CType(node.ReturnType)} {node.Name.Ident}({string.Join(", ", parameters)})");
+            writer.WriteLine($"{CType(node.ReturnType, node.Name.Ident)}({string.Join(", ", parameters)})");
             writer.WriteLine("{");
             using (writer.Indent())
             {
@@ -56,6 +56,9 @@ public sealed class Generator(List<NodeDefinition> nodes)
             case NodeStatementFuncCall statement:
                 EmitStatementFuncCall(statement);
                 break;
+            case NodeStatementReturn statement:
+                EmitStatementReturn(statement);
+                break;
         }
     }
 
@@ -78,6 +81,12 @@ public sealed class Generator(List<NodeDefinition> nodes)
         writer.WriteLine($"{name}({string.Join(", ", parameterValues)});");
     }
 
+    private void EmitStatementReturn(NodeStatementReturn statement)
+    {
+        var value = EmitExpression(statement.Value);
+        writer.WriteLine($"return {value};");
+    }
+
     private string EmitExpression(NodeExpression node)
     {
         return node switch
@@ -109,36 +118,63 @@ public sealed class Generator(List<NodeDefinition> nodes)
         return expression.Value.Ident;
     }
 
-    private static string CType(NodeType node)
+    private static string CType(NodeType type, string? variableName = null)
     {
-        return node switch
+        return type switch
         {
-            NodeTypeCustom type => $"struct {type.Name.Ident}",
+            NodeTypeVoid => "void" + (variableName != null ? $" {variableName}" : ""),
-            NodeTypeFloat type => type.Width switch
+            NodeTypeBool => "bool" + (variableName != null ? $" {variableName}" : ""),
-            {
+            NodeTypeSInt intType => CTypeSInt(intType, variableName),
-                32 => "float",
+            NodeTypeUInt intType => CTypeUInt(intType, variableName),
-                64 => "double",
+            NodeTypePointer ptr => CType(ptr.To) + "*" + (variableName != null ? $" {variableName}" : ""),
-            },
+            NodeTypeString => "struct string" + (variableName != null ? $" {variableName}" : ""),
-            NodeTypePointer type => $"{CType(type.To)}*",
+            NodeTypeFunc fn => CTypeFunc(fn, variableName),
-            NodeTypeSInt type => type.Width switch
-            {
-                8 => "byte",
-                16 => "short",
-                32 => "int",
-                64 => "long",
-            },
-            NodeTypeUInt type => type.Width switch
-            {
-                8 => "unsigned byte",
-                16 => "unsigned short",
-                32 => "unsigned int",
-                64 => "unsigned long",
-            },
-            NodeTypeString => "struct string",
-            NubTypeVoid => "void",
-            _ => throw new ArgumentOutOfRangeException(nameof(node))
         };
     }
+
+    private static string CTypeSInt(NodeTypeSInt intType, string? varName)
+    {
+        var cType = intType.Width switch
+        {
+            8 => "char",
+            16 => "short",
+            32 => "int",
+            64 => "long long",
+        };
+
+        return cType + (varName != null ? $" {varName}" : "");
+    }
+
+    private static string CTypeUInt(NodeTypeUInt intType, string? varName)
+    {
+        var cType = intType.Width switch
+        {
+            8 => "unsigned char",
+            16 => "unsigned short",
+            32 => "unsigned int",
+            64 => "unsigned long long",
+        };
+
+        return cType + (varName != null ? $" {varName}" : "");
+    }
+
+    private static string CTypeFunc(NodeTypeFunc fn, string? varName)
+    {
+        var returnType = CType(fn.ReturnType);
+        var parameters = string.Join(", ", fn.Parameters.Select(p => CType(p)));
+
+        if (string.IsNullOrEmpty(parameters))
+        {
+            parameters = "void";
+        }
+
+        if (varName != null)
+        {
+            return $"{returnType} (*{varName})({parameters})";
+        }
+
+        return $"{returnType} (*)({parameters})";
+    }
 }
 
 internal class IndentedTextWriter

compiler/Compiler/Parser.cs

@@ -64,6 +64,12 @@ public sealed class Parser(List<Token> tokens)
             return new NodeStatementBlock(TokensFrom(startIndex), statements);
         }
 
+        if (TryExpectKeyword(Keyword.Return))
+        {
+            var value = ParseExpression();
+            return new NodeStatementReturn(TokensFrom(startIndex), value);
+        }
+
         var expression = ParseExpression();
         var parameters = new List<NodeExpression>();
 
@@ -111,14 +117,32 @@ public sealed class Parser(List<Token> tokens)
             return new NodeTypePointer(TokensFrom(startIndex), to);
         }
 
+        if (TryExpectKeyword(Keyword.Func))
+        {
+            var parameters = new List<NodeType>();
+
+            ExpectSymbol(Symbol.OpenParen);
+            while (!TryExpectSymbol(Symbol.CloseParen))
+            {
+                parameters.Add(ParseType());
+            }
+
+            ExpectSymbol(Symbol.Colon);
+            var returnType = ParseType();
+
+            return new NodeTypeFunc(TokensFrom(startIndex), parameters, returnType);
+        }
+
         if (TryExpectIdent(out var ident))
         {
             switch (ident.Ident)
             {
                 case "void":
-                    return new NubTypeVoid(TokensFrom(startIndex));
+                    return new NodeTypeVoid(TokensFrom(startIndex));
                 case "string":
                     return new NodeTypeString(TokensFrom(startIndex));
+                case "bool":
+                    return new NodeTypeBool(TokensFrom(startIndex));
                 case "i8":
                     return new NodeTypeSInt(TokensFrom(startIndex), 8);
                 case "i16":
@@ -135,10 +159,6 @@ public sealed class Parser(List<Token> tokens)
                     return new NodeTypeUInt(TokensFrom(startIndex), 32);
                 case "u64":
                     return new NodeTypeUInt(TokensFrom(startIndex), 64);
-                case "f32":
-                    return new NodeTypeFloat(TokensFrom(startIndex), 32);
-                case "f64":
-                    return new NodeTypeFloat(TokensFrom(startIndex), 64);
                 default:
                     return new NodeTypeCustom(TokensFrom(startIndex), ident);
             }
@@ -272,8 +292,7 @@ public abstract class Node(List<Token> tokens)
 
 public abstract class NodeDefinition(List<Token> tokens) : Node(tokens);
 
-public sealed class NodeDefinitionFunc(List<Token> tokens, TokenIdent name, List<NodeDefinitionFunc.Param> parameters, NodeStatement body, NodeType returnType)
+public sealed class NodeDefinitionFunc(List<Token> tokens, TokenIdent name, List<NodeDefinitionFunc.Param> parameters, NodeStatement body, NodeType returnType) : NodeDefinition(tokens)
-    : NodeDefinition(tokens)
 {
     public readonly TokenIdent Name = name;
     public readonly List<Param> Parameters = parameters;
@@ -300,6 +319,11 @@ public sealed class NodeStatementFuncCall(List<Token> tokens, NodeExpression fun
     public readonly List<NodeExpression> Parameters = parameters;
 }
 
+internal class NodeStatementReturn(List<Token> tokens, NodeExpression value) : NodeStatement(tokens)
+{
+    public readonly NodeExpression Value = value;
+}
+
 public abstract class NodeExpression(List<Token> tokens) : Node(tokens);
 
 public sealed class NodeExpressionIntLiteral(List<Token> tokens, TokenIntLiteral value) : NodeExpression(tokens)
@@ -324,7 +348,7 @@ public sealed class NodeExpressionIdent(List<Token> tokens, TokenIdent value) :
 
 public abstract class NodeType(List<Token> tokens) : Node(tokens);
 
-public sealed class NubTypeVoid(List<Token> tokens) : NodeType(tokens);
+public sealed class NodeTypeVoid(List<Token> tokens) : NodeType(tokens);
 
 public sealed class NodeTypeUInt(List<Token> tokens, int width) : NodeType(tokens)
 {
@@ -336,10 +360,7 @@ public sealed class NodeTypeSInt(List<Token> tokens, int width) : NodeType(token
     public readonly int Width = width;
 }
 
-public sealed class NodeTypeFloat(List<Token> tokens, int width) : NodeType(tokens)
+public sealed class NodeTypeBool(List<Token> tokens) : NodeType(tokens);
-{
-    public readonly int Width = width;
-}
 
 public sealed class NodeTypeString(List<Token> tokens) : NodeType(tokens);
 
@@ -352,3 +373,9 @@ public sealed class NodeTypePointer(List<Token> tokens, NodeType to) : NodeType(
 {
     public readonly NodeType To = to;
 }
+
+public sealed class NodeTypeFunc(List<Token> tokens, List<NodeType> parameters, NodeType returnType) : NodeType(tokens)
+{
+    public readonly List<NodeType> Parameters = parameters;
+    public readonly NodeType ReturnType = returnType;
+}

compiler/Compiler/Program.cs

@@ -1,11 +1,12 @@
 using Compiler;
 
 const string contents = """
-                        func main(): void {
+                        func main(): i32 {
                             do_something("test")
+                            return 69
                         }
                         
-                        func do_something(text: string): void {
+                        func do_something(text: string): func(i32 u32): void {
                         }
                         """;
 

compiler/Compiler/Tokenizer.cs

@@ -279,6 +279,7 @@ public sealed class Tokenizer(string contents)
                         "func" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Func),
                         "let" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Let),
                         "if" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.If),
+                        "return" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Return),
                         "true" => new TokenBoolLiteral(line, startColumn, column - startColumn, true),
                         "false" => new TokenBoolLiteral(line, startColumn, column - startColumn, false),
                         _ => new TokenIdent(line, startColumn, column - startColumn, value)
@@ -397,6 +398,7 @@ public enum Keyword
     Func,
     Let,
     If,
+    Return,
 }
 
 public sealed class TokenKeyword(int line, int column, int length, Keyword keyword) : Token(line, column, length)