private void Function(FunctionType type)
{
current = new Instance {
type = type,
enclosing = current
};
current.function.name = ObjString.CopyString(parser.previous.Lexeme);
BeginScope();
Consume(TokenType.LeftParen, "Expect '(' after function name.");
if (!Check(TokenType.RightParen))
{
do
{
current.function.arity += 1;
if (current.function.arity > 255)
{
ErrorAtCurrent("Can't have more than 255 parameters.");
}
byte paramConst = ParseVariable("Expect parameter name.");
DefineVariable(paramConst);
} while (Match(TokenType.Comma));
}
Consume(TokenType.RightParen, "Expect ')' after parameters.");
Consume(TokenType.LeftBrace, "Expect '{' before function body.");
Block();
ObjFunction fun = EndCompiler();
EmitBytes(OpCode.Constant, MakeConstant(Value.Obj(fun)));
}
internal Instance()
{
locals = new Local[byte.MaxValue];
localCount = 0;
scopeDepth = 0;
function = new ObjFunction();
locals[localCount++] = new Local {
depth = 0,
name = new Token {
Lexeme = "",
}
};
}
private ObjFunction EndCompiler()
{
EmitReturn();
ObjFunction fun = current.function;
#if DEBUG
if (!parser.hadError)
{
CurrentChunk().Disassemble(writer, fun.name == null ? "<script>" : fun.name.Chars);
}
#endif
current = current.enclosing;
return(fun);
}
internal ObjFunction Compile(TextWriter writer, string source)
{
scanner = new Scanner(source);
this.writer = writer;
parser.hadError = false;
parser.panicMode = false;
Advance();
while (!Match(TokenType.Eof))
{
Declaration();
}
ObjFunction fun = EndCompiler();
return(parser.hadError ? null : fun);
}
private void RuntimeError(string format, params object[] args)
{
CallFrame frame = frames[frameCount - 1];
int line = frame.function.chunk.GetLine(frame.ip);
writer.WriteLine(format, args);
for (int i = frameCount - 1; i >= 0; i -= 1)
{
CallFrame f = frames[i];
ObjFunction func = f.function;
int instruction = frame.ip - 1;
writer.WriteLine($"[line {func.chunk.GetLine(instruction)} in {(func.name == null ? "<script>" : func.name.Chars)}");
}
ResetStack();
}
private bool Call(ObjFunction function, int argCount)
{
if (argCount != function.arity)
{
RuntimeError("Expected {0} arguments but got {1}", function.arity, argCount);
return(false);
}
if (frameCount == FramesMax)
{
RuntimeError("Stack overflow.");
return(false);
}
frames[frameCount++] = new CallFrame {
function = function,
ip = 0,
slots = stack.Slice(stackTop - argCount - 1),
};
return(true);
}
