Strings 19

src/clox/vm.d

@@ -7,6 +7,7 @@ import clox.value;
 import clox.dbg;
 import clox.util;
 import clox.compiler;
+import clox.object;
 import clox.container.stack;
 import clox.container.varint;
 import clox.container.int24;
@@ -17,10 +18,14 @@ struct VM{
 	const(ubyte)* ip;
 	Stack!(Value, stackMax) stack;
 	Chunk* chunk;
+	Obj* objects;
 	enum InterpretResult{ Ok, CompileError, RuntimeError }
 	this(int _) @nogc nothrow {
 		stack = typeof(stack)(0);
 	}
+	~this(){
+		freeObjects();
+	}
 	InterpretResult interpret(string source){
 		Chunk c = Chunk();
 		Compiler compiler;
@@ -56,7 +61,7 @@ struct VM{
 		}
 		while(true){
 			debug(traceExec){
-				writeln("          ", stack.live);
+				stderr.writeln("          ", stack.live);
 				disassembleInstruction(chunk, ip - &chunk.code[0]);
 			}
 			OpCode instruction = readIns();
@@ -76,6 +81,15 @@ struct VM{
 					break;
 				static foreach(k, op; [ Add: "+", Subtract: "-", Multiply: "*", Divide: "/" ]){
 					case k:
+						static if(k == Add){
+							if(peek(0).isStr && peek(1).isStr){
+								const(Obj.String)* b = stack.pop().getStr;
+								const(Obj.String)* a = stack.pop().getStr;
+								Obj.String* newStr = Obj.String.concat(a, b, &this);
+								stack.push(Value.str(newStr));
+								break opSwitch;
+							}
+						}
 						if(!peek(0).isNum || !peek(1).isNum){
 							runtimeError("Operands must be numbers.");
 							return InterpretResult.RuntimeError;
@@ -104,11 +118,18 @@ struct VM{
 					break;
 				case Return:
 					debug printValue(stack.pop());
-					debug writeln();
+					debug stderr.writeln();
 					return InterpretResult.Ok;
 			}
 		}
 		assert(0);
 	}
+	void freeObjects(){
+		for(Obj* obj = objects; obj !is null;){
+			Obj* next = obj.next;
+			obj.freeObject();
+			obj = next;
+		}
+	}
 }