refactor(strings): replace compiler builtins with the STRING library

Construct literals as STRING values and route string operations through
ordinary library functions and operators. Preserve value ownership in
records, arrays, constants and file I/O.

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

1 files changed, 24 insertions, 14 deletions

diff --git a/lib/CodeGen/StatementGen.cc b/lib/CodeGen/StatementGen.cc
index c0bc223..5b60d29 100644
--- a/lib/CodeGen/StatementGen.cc
+++ b/lib/CodeGen/StatementGen.cc
@@ -97,7 +97,7 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
     if (auto *Call = dynamic_cast<MemberCallStmtAST*>(Stmt)) {
         Value *Result = emitMemberCall(Call->getCall());
         const TypeInfo *Type = getExprTypeInfo(Call->getCall());
-        if (Result && Type && Type->IsClass) materializeOperatorReceiver(Result, Type);
+        if (Result && Type && (Type->IsClass || containsString(Type))) materializeOperatorReceiver(Result, Type);
         return;
     }
 
@@ -106,7 +106,7 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
         const FuncSig *Sig = FuncGen->hasFunction(Call->getCallee())
             ? resolveCall(Call->getCallee(), Call->getArgs()) : nullptr;
         const TypeInfo *Type = Sig ? resolveType(Sig->ReturnTypeName) : nullptr;
-        if (Result && Type && Type->IsClass) materializeOperatorReceiver(Result, Type);
+        if (Result && Type && (Type->IsClass || containsString(Type))) materializeOperatorReceiver(Result, Type);
         return;
     }
 
@@ -195,11 +195,7 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
             Value *BoolVal = Builder->CreateICmpNE(Val, ConstantInt::get(*TheContext, APInt(64, 0)), "bool_cast");
             Builder->CreateStore(BoolVal, Target.Addr);
         } else if (TypeInfo->isString()) {
-            Value *Mem = Builder->CreateCall(MallocFunc, ConstantInt::get(*TheContext, APInt(64, 1024)), "input_str");
-            Args.push_back(ScanfStringFormatStr);
-            Args.push_back(Mem);
-            Builder->CreateCall(ScanfFunc, Args);
-            Builder->CreateStore(Mem, Target.Addr);
+            emitMethodCall(TypeInfo->Name, Target.Addr, "READ_INPUT", {}, Stmt->getLine());
         } else if (TypeInfo->isChar()) {
             Value *CharFmt = Builder->CreateGlobalString(" %c", "fmt_in_char", 0, TheModule.get());
             Args.push_back(CharFmt);
@@ -233,6 +229,8 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
                 reportError("Cannot OUTPUT the result of a PROCEDURE call");
                 continue;
             }
+            if (TypeInfo->IsClass && !isObjectLValue(Expr))
+                materializeOperatorReceiver(Val, TypeInfo);
             emitOutputValue(Val, TypeInfo, I + 1 == Exprs.size());
         }
         return;
@@ -243,7 +241,7 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
             reportError("Cannot use a whole array as the OPENFILE filename");
             return;
         }
-        Value *Name = emitCoercedExpr(Open->getFileName(), resolveType("STRING"));
+        Value *Name = emitCStringExpr(Open->getFileName());
         if (!Name) return;
         Files->emitOpen(Name, Open->getMode(), Open->getLine());
         return;
@@ -260,7 +258,7 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
             reportError("READFILE into entire array %s is not supported", Read->getVarName().c_str());
             return;
         }
-        if (Info->TypeName != "STRING") {
+        if (!sameIdentifier(Info->TypeName, "STRING")) {
             reportError("READFILE variable %s must be of type STRING (got %s)",
                         Read->getVarName().c_str(), Info->TypeName.c_str());
             return;
@@ -269,11 +267,23 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
             reportError("Cannot use a whole array as the READFILE filename");
             return;
         }
-        Value *Name = emitCoercedExpr(Read->getFileName(), resolveType("STRING"));
+        Value *Name = emitCStringExpr(Read->getFileName());
         if (!Name) return;
         Value *LineStr = Files->emitRead(Name, Read->getLine());
         if (!LineStr) return;
-        Builder->CreateStore(LineStr, Info->Storage);
+        const auto *Type = resolveType(Info->TypeName);
+        for (const FuncSig *Sig : FuncGen->getOverloads(Type->Name + ".OPERATOR <-")) {
+            if (Sig->Params.size() == 1 && !Sig->Params[0].IsByRef &&
+                resolveType("C_STRING")->sameType(resolveType(Sig->Params[0].TypeName)) &&
+                checkOperatorAccess(*Sig)) {
+                FuncGen->emitCall(*Sig, {symbolAddress(*Info), LineStr});
+                auto Free = TheModule->getOrInsertFunction("free", FunctionType::get(
+                    Type::getVoidTy(*TheContext), {PointerType::getUnqual(*TheContext)}, false));
+                Builder->CreateCall(Free, {LineStr});
+                return;
+            }
+        }
+        reportError("READFILE requires STRING.OPERATOR<-(Text : C_STRING)");
         return;
     }
 
@@ -282,8 +292,8 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
             reportError("Cannot use a whole array in WRITEFILE");
             return;
         }
-        Value *Name = emitCoercedExpr(Write->getFileName(), resolveType("STRING"));
-        Value *Data = emitCoercedExpr(Write->getData(), resolveType("STRING"));
+        Value *Name = emitCStringExpr(Write->getFileName());
+        Value *Data = emitCStringExpr(Write->getData());
         if (!Name || !Data) return;
         Files->emitWrite(Name, Data, Write->getLine());
         return;
@@ -294,7 +304,7 @@ void CodeGen::emitStmtImpl(StmtAST *Stmt) {
             reportError("Cannot use a whole array as the CLOSEFILE filename");
             return;
         }
-        Value *Name = emitCoercedExpr(Close->getFileName(), resolveType("STRING"));
+        Value *Name = emitCStringExpr(Close->getFileName());
         if (!Name) return;
         Files->emitClose(Name, Close->getLine());
         return;