...

src/compiler/Nub.Lang/Frontend/Parsing/FuncDefinitionNode.cs

@@ -8,10 +8,41 @@ public interface IFuncSignature
     public List<FuncParameter> Parameters { get; }
     public Optional<NubType> ReturnType { get; }
 
+    public bool SignatureMatches(string name, List<NubType> parameters)
+    {
+        if (Name != name) return false;
+        if (Parameters.Count == 0 && parameters.Count == 0) return true;
+        if (Parameters.Count > parameters.Count) return false;
+            
+        for (var i = 0; i < parameters.Count; i++)
+        {
+            if (i > Parameters.Count)
+            {
+                if (Parameters[^1].Variadic)
+                {
+                    if (!NubType.IsCompatibleWith(parameters[i], Parameters[^1].Type))
+                    {
+                        return false;
+                    }
+                }
+                else
+                {
+                    return false;
+                }
+            }
+            else if (!NubType.IsCompatibleWith(parameters[i], Parameters[i].Type))
+            {
+                return false;
+            }
+        }
+            
+        return true;
+    }
+
     public string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
 }
 
-public class LocalFuncDefinitionNode(IReadOnlyList<Token> tokens, Optional<string> documentation, string name, List<FuncParameter> parameters, BlockNode body, Optional<NubType> returnType, bool global) : DefinitionNode(tokens, documentation)
+public class LocalFuncDefinitionNode(IReadOnlyList<Token> tokens, Optional<string> documentation, string name, List<FuncParameter> parameters, BlockNode body, Optional<NubType> returnType, bool global) : DefinitionNode(tokens, documentation), IFuncSignature
 {
     public string Name { get; } = name;
     public List<FuncParameter> Parameters { get; } = parameters;