Refactor statements

src/lang/Nub.Lang/Frontend/Parsing/Definitions/FuncDefinitionNode.cs

@@ -0,0 +1,73 @@
+using Nub.Lang.Frontend.Lexing;
+using Nub.Lang.Frontend.Typing;
+
+namespace Nub.Lang.Frontend.Parsing;
+
+public class FuncParameter(string name, NubType type, bool variadic)
+{
+    public string Name { get; } = name;
+    public NubType Type { get; } = type;
+    public bool Variadic { get; } = variadic;
+
+    public override string ToString() => $"{Name}: {Type}";
+}
+
+public interface IFuncSignature
+{
+    public string Name { get; }
+    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 exported) : DefinitionNode(tokens, documentation), IFuncSignature
+{
+    public string Name { get; } = name;
+    public List<FuncParameter> Parameters { get; } = parameters;
+    public BlockNode Body { get; } = body;
+    public Optional<NubType> ReturnType { get; } = returnType;
+    public bool Exported { get; } = exported;
+
+    public override string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
+}
+
+public class ExternFuncDefinitionNode(IReadOnlyList<Token> tokens, Optional<string> documentation, string name, List<FuncParameter> parameters, Optional<NubType> returnType) : DefinitionNode(tokens, documentation), IFuncSignature
+{
+    public string Name { get; } = name;
+    public List<FuncParameter> Parameters { get; } = parameters;
+    public Optional<NubType> ReturnType { get; } = returnType;
+
+    public override string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
+}