feat(classes): overload methods and NEW constructors

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

11 files changed, 139 insertions, 18 deletions

diff --git a/include/cps/CodeGen.h b/include/cps/CodeGen.h
index 463c613..04bf25c 100644
--- a/include/cps/CodeGen.h
+++ b/include/cps/CodeGen.h
@@ -43,9 +43,12 @@ class CodeGen {
     void importSymbols();
     void runGlobalPrePass(const SourceUnit &Unit, int Phase);
     IdentifierMap<SymbolInfo> Symbols;
-    IdentifierMap<IdentifierMap<FunctionDefAST*>> ClassMethods;
+    IdentifierMap<IdentifierMap<std::vector<FunctionDefAST*>>> ClassMethods;
     std::string CurrentClass;
-    const PrototypeAST *findMethod(const std::string &Class, const std::string &Name) const;
+    const std::vector<FunctionDefAST *> *findMethod(const std::string &Class, const std::string &Name) const;
+    bool isRegisteredMethod(const std::string &Class, const PrototypeAST *Method) const;
+    const FuncSig *resolveMethod(const std::string &Class, const std::string &Name,
+                                 const std::vector<std::unique_ptr<ExprAST>> &Args);
     llvm::Value *emitMemberCall(MemberCallExprAST *Call);
     llvm::Value *emitMethodCall(const std::string &Class, llvm::Value *Receiver,
                                 const std::string &Name,
diff --git a/lib/CodeGen/CodeGen.cc b/lib/CodeGen/CodeGen.cc
index 9f59a4d..92a52e8 100644
--- a/lib/CodeGen/CodeGen.cc
+++ b/lib/CodeGen/CodeGen.cc
@@ -288,7 +288,7 @@ void CodeGen::compile(const std::vector<SourceUnit> &Sources) {
             if (auto *Class = dynamic_cast<ClassTypeDeclAST*>(Stmt.get())) {
                 for (const auto &Method : Class->getMethods()) {
                     SaveAndRestore<int> MethodLocation(DiagnosticLine, Method->getLine());
-                    if (findMethod(Class->getName(), Method->getProto()->getName()) == Method->getProto())
+                    if (isRegisteredMethod(Class->getName(), Method->getProto()))
                         FuncGen->emitPrototype(Method->getProto());
                 }
             }
diff --git a/lib/CodeGen/Designator.cc b/lib/CodeGen/Designator.cc
index 540059d..467f788 100644
--- a/lib/CodeGen/Designator.cc
+++ b/lib/CodeGen/Designator.cc
@@ -59,20 +59,40 @@ void CodeGen::runTypePrePass(const std::vector<std::unique_ptr<StmtAST>> &Statem
             const std::string &Name = Method->getProto()->getName();
             if (sameIdentifier(Name, "this")) {
                 reportError("A method cannot be named this");
-            } else if (!Names.insert(Name).second) {
+            } else if (Names.count(Name) ||
+                       (!Methods[Name].empty() && (!Method->getProto()->isOverload() ||
+                                                 !Methods[Name].front()->getProto()->isOverload()))) {
                 reportError("Duplicate member %s in class %s", Name.c_str(), Class->getName().c_str());
             } else {
-                Methods.emplace(Name, Method.get());
+                Methods[Name].push_back(Method.get());
             }
         }
     }
 }
 
-const PrototypeAST *CodeGen::findMethod(const std::string &Class, const std::string &Name) const {
+const std::vector<FunctionDefAST *> *CodeGen::findMethod(const std::string &Class, const std::string &Name) const {
     auto C = ClassMethods.find(Class);
     if (C == ClassMethods.end()) return nullptr;
     auto M = C->second.find(Name);
-    return M == C->second.end() ? nullptr : M->second->getProto();
+    return M == C->second.end() || M->second.empty() ? nullptr : &M->second;
+}
+
+bool CodeGen::isRegisteredMethod(const std::string &Class, const PrototypeAST *Method) const {
+    const auto *Methods = findMethod(Class, Method->getName());
+    if (Methods)
+        for (const auto *Candidate : *Methods)
+            if (Candidate->getProto() == Method) return true;
+    return false;
+}
+
+const FuncSig *CodeGen::resolveMethod(const std::string &Class, const std::string &Name,
+                                    const std::vector<std::unique_ptr<ExprAST>> &Args) {
+    const auto *Methods = findMethod(Class, Name);
+    if (!Methods) {
+        reportError("Type %s has no method %s", Class.c_str(), Name.c_str());
+        return nullptr;
+    }
+    return resolveCall(Methods->front()->getProto()->getLinkName(), Args);
 }
 
 Value *CodeGen::emitMemberCall(MemberCallExprAST *Call) {
@@ -87,18 +107,15 @@ Value *CodeGen::emitMethodCall(const std::string &Class, Value *Receiver,
                                 const std::string &Name,
                                 const std::vector<std::unique_ptr<ExprAST>> &ArgExprs, int Line) {
     SaveAndRestore<int> Location(DiagnosticLine, Line);
-    const PrototypeAST *Method = findMethod(Class, Name);
-    if (!Method) {
-        reportError("Type %s has no method %s", Class.c_str(), Name.c_str());
-        return nullptr;
-    }
+    const FuncSig *Sig = resolveMethod(Class, Name, ArgExprs);
+    if (!Sig) return nullptr;
+    const PrototypeAST *Method = Sig->Prototype;
     if (!Method->isPublic() && !sameIdentifier(CurrentClass, Class)) {
         reportError("Cannot access private method %s of type %s", Name.c_str(), Class.c_str());
         return nullptr;
     }
     std::vector<Value*> Args = {Receiver};
-    const FuncSig *Sig = resolveCall(Method->getLinkName(), ArgExprs);
-    if (!Sig || !marshalCallArgs(*Sig, ArgExprs, Line, Args)) return nullptr;
+    if (!marshalCallArgs(*Sig, ArgExprs, Line, Args)) return nullptr;
     return FuncGen->emitCall(Sig->LinkName, Args);
 }
 
diff --git a/lib/CodeGen/StatementGen.cc b/lib/CodeGen/StatementGen.cc
index 8783cde..022c550 100644
--- a/lib/CodeGen/StatementGen.cc
+++ b/lib/CodeGen/StatementGen.cc
@@ -19,7 +19,7 @@ void CodeGen::emitStmt(StmtAST *Stmt) {
     if (auto *Class = dynamic_cast<ClassTypeDeclAST*>(Stmt)) {
         for (const auto &Method : Class->getMethods()) {
             // Invalid or duplicate members have already been diagnosed.
-            if (findMethod(Class->getName(), Method->getProto()->getName()) == Method->getProto())
+            if (isRegisteredMethod(Class->getName(), Method->getProto()))
                 emitStmt(Method.get());
         }
         return;
diff --git a/lib/CodeGen/ValueTypeGen.cc b/lib/CodeGen/ValueTypeGen.cc
index d2bba03..3c1fc06 100644
--- a/lib/CodeGen/ValueTypeGen.cc
+++ b/lib/CodeGen/ValueTypeGen.cc
@@ -119,9 +119,9 @@ const TypeInfo *CodeGen::getExprTypeInfo(ExprAST *Expr) {
 
     if (auto *Call = dynamic_cast<MemberCallExprAST*>(Expr)) {
         const TypeInfo *Receiver = getExprTypeInfo(Call->getReceiver());
-        const PrototypeAST *Method = Receiver ? findMethod(Receiver->Name, Call->getMethod()) : nullptr;
-        if (!Method || (!Method->isPublic() && !sameIdentifier(CurrentClass, Receiver->Name))) return nullptr;
-        return resolveType(Method->getReturnType());
+        const FuncSig *Sig = Receiver ? resolveMethod(Receiver->Name, Call->getMethod(), Call->getArgs()) : nullptr;
+        if (!Sig || (!Sig->Prototype->isPublic() && !sameIdentifier(CurrentClass, Receiver->Name))) return nullptr;
+        return resolveType(Sig->ReturnTypeName);
     }
 
     if (auto *Call = dynamic_cast<CallExprAST*>(Expr)) {
diff --git a/tests/i/class-overload-methods/case.json b/tests/i/class-overload-methods/case.json
new file mode 100644
index 0000000..0967ef4
--- /dev/null
+++ b/tests/i/class-overload-methods/case.json
@@ -0,0 +1 @@
+{}
diff --git a/tests/i/class-overload-methods/expected.txt b/tests/i/class-overload-methods/expected.txt
new file mode 100644
index 0000000..d7fa519
--- /dev/null
+++ b/tests/i/class-overload-methods/expected.txt
@@ -0,0 +1,7 @@
+174
+11
+9
+ok!
+3
+8
+1
diff --git a/tests/i/class-overload-methods/notes.md b/tests/i/class-overload-methods/notes.md
new file mode 100644
index 0000000..accde5e
--- /dev/null
+++ b/tests/i/class-overload-methods/notes.md
@@ -0,0 +1,7 @@
+# class-overload-methods
+
+Human review: pending. Expected output was independently traced by AI, not captured from cpsc.
+
+Basis: OVERLOAD is a project extension.
+
+Trace: The default constructor sets 1, INTEGER sets 7, STRING length sets 4. Holder.Item and both array elements default to 1. Get(INTEGER) adds 2 to 7; Get(STRING) appends !. Set(STRING) stores length 3. Keyword NEW stores 8; explicit NEW() resets to 1.
diff --git a/tests/i/class-overload-methods/program.cps b/tests/i/class-overload-methods/program.cps
new file mode 100644
index 0000000..e68d416
--- /dev/null
+++ b/tests/i/class-overload-methods/program.cps
@@ -0,0 +1,46 @@
+CLASS Box
+Value : INTEGER
+PUBLIC OVERLOAD PROCEDURE NEW()
+Value <- 1
+ENDPROCEDURE
+PUBLIC OVERLOAD PROCEDURE NEW(x : INTEGER)
+Value <- x
+ENDPROCEDURE
+PUBLIC OVERLOAD PROCEDURE NEW(x : STRING)
+Value <- LENGTH(x)
+ENDPROCEDURE
+OVERLOAD FUNCTION Get() RETURNS INTEGER
+RETURN Value
+ENDFUNCTION
+OVERLOAD FUNCTION Get(x : INTEGER) RETURNS INTEGER
+RETURN Value + x
+ENDFUNCTION
+OVERLOAD FUNCTION Get(x : STRING) RETURNS STRING
+RETURN x & "!"
+ENDFUNCTION
+OVERLOAD PROCEDURE Set(x : INTEGER)
+Value <- x
+ENDPROCEDURE
+OVERLOAD PROCEDURE Set(x : STRING)
+Value <- LENGTH(x)
+ENDPROCEDURE
+ENDCLASS
+TYPE Holder
+DECLARE Item : Box
+ENDTYPE
+DECLARE a : Box
+DECLARE b : Box(7)
+DECLARE c : Box("four")
+DECLARE h : Holder
+DECLARE items : ARRAY[1:2] OF Box
+OUTPUT a.Get(), b.Get(), c.Get()
+OUTPUT h.Item.Get(), items[2].Get()
+OUTPUT b.Get(2)
+OUTPUT b.Get("ok")
+CALL a.Set("abc")
+OUTPUT a.Get()
+a <- NEW Box(8)
+OUTPUT a.Get()
+CALL a.NEW()
+OUTPUT a.Get()
+DELETE a
diff --git a/tests/iii/class-overload-errors/case.json b/tests/iii/class-overload-errors/case.json
new file mode 100644
index 0000000..afc0e6a
--- /dev/null
+++ b/tests/iii/class-overload-errors/case.json
@@ -0,0 +1,20 @@
+{
+  "errors": [
+    {
+      "reason": "Duplicate member Set in class Mixed",
+      "line": 4
+    },
+    {
+      "reason": "No matching overload for Required.NEW\\(\\)",
+      "line": 17
+    },
+    {
+      "reason": "Cannot access private method Set of type Secret",
+      "line": 19
+    },
+    {
+      "reason": "No matching overload for Secret.Set\\(BOOLEAN\\)",
+      "line": 20
+    }
+  ]
+}
diff --git a/tests/iii/class-overload-errors/program.cps b/tests/iii/class-overload-errors/program.cps
new file mode 100644
index 0000000..586d47d
--- /dev/null
+++ b/tests/iii/class-overload-errors/program.cps
@@ -0,0 +1,20 @@
+CLASS Mixed
+OVERLOAD PROCEDURE Set(x : INTEGER)
+ENDPROCEDURE
+PROCEDURE Set(x : STRING)
+ENDPROCEDURE
+ENDCLASS
+CLASS Required
+OVERLOAD PROCEDURE NEW(x : INTEGER)
+ENDPROCEDURE
+ENDCLASS
+CLASS Secret
+PRIVATE OVERLOAD PROCEDURE Set(x : INTEGER)
+ENDPROCEDURE
+PUBLIC OVERLOAD PROCEDURE Set(x : STRING)
+ENDPROCEDURE
+ENDCLASS
+DECLARE item : Required
+DECLARE obj : Secret
+CALL obj.Set(1)
+CALL obj.Set(TRUE)