protected void ResolveFunCallExpr(AstFunCallExpr expr)
{
ResolveExpr(expr.m_callee);
foreach (AstExpr arg in expr.m_args)
{
ResolveExpr(arg);
}
}
protected object EvaluateFunCallExpr(AstFunCallExpr expr)
{
if (HadErrorOrReturn())
{
return(null);
}
object calleeObj = EvaluateExpr(expr.m_callee);
IFunction callee = calleeObj as IFunction;
if (callee != null)
{
if (expr.m_args.Count != callee.ArgCount())
{
// TODO: print function name in the error
m_runtimeError = true;
Lox.Error(expr.m_startLine, "Function expected " + callee.ArgCount() + " arguments, but was passed " + expr.m_args.Count);
return(null);
}
List <object> args = new List <object>();
foreach (AstExpr argExpr in expr.m_args)
{
args.Add(EvaluateExpr(argExpr));
}
return(callee.Call(this, args));
}
else
{
// TODO: Distinguish between someUnknownFunction() and (3 + 1)() ?
// It would be nice to be able to print the name of the function in the former case
m_runtimeError = true;
Lox.Error(expr.m_startLine, "Invalid function call");
return(null);
}
}
protected AstExpr ParseFunCallExpr()
{
AstExpr expr = ParsePrimaryExpr();
if (expr == null)
{
return(EmptyErrorExpr());
}
Token token;
// NOTE (andrews) While loop handles chained function calls and member access like this:
// some.member.functionThatReturnsFunction()();
while (true)
{
if ((token = TryMatch(TOKENK.OpenParen)) != null)
{
bool isFirstArg = true;
List <AstExpr> args = new List <AstExpr>();
while ((token = TryMatch(TOKENK.CloseParen)) == null)
{
if (!isFirstArg)
{
AstExpr prevArg = args[args.Count - 1];
if ((token = TryMatch(TOKENK.Comma)) == null)
{
return(ErrorExpr(prevArg.m_startLine, "Expected ',' in argument list"));
}
if (args.Count == AstFunCallExpr.s_maxArgCount)
{
// NOTE (andrews) This isn't a parse error so we don't return ErrorExpr like we do for other parse errors.
// This lets us report it while continuing the parse in case we find other errors.
Lox.Error(prevArg.m_startLine, "Cannot exceed " + AstFunCallExpr.s_maxArgCount + " arguments");
}
}
AstExpr arg = ParseExpr();
if (arg == null)
{
return(EmptyErrorExpr());
}
args.Add(arg);
isFirstArg = false;
}
expr = new AstFunCallExpr(expr, args);
}
else if ((token = TryMatch(TOKENK.Dot)) != null)
{
if ((token = TryMatch(TOKENK.Identifier)) != null)
{
expr = new AstVarExpr(expr, token);
}
}
else
{
return(expr);
}
}
}
