protected void ResolveVarExpr(AstVarExpr expr)
{
var scope = Scope();
if (scope == null)
{
return; // TODO: Better global handling
}
if (expr.m_instance != null)
{
// Can't resolve properties (i.e., right-hand side of .), but we still want to resolve the instance (i.e., left-hand-side of .)
ResolveExpr(expr.m_instance);
}
else
{
if (scope.ContainsKey(expr.m_identifier.m_identifier) && !scope[expr.m_identifier.m_identifier])
{
m_error = true;
Lox.Error(expr.m_startLine, "Cannot use identifier \"" + expr.m_identifier.m_identifier + "\" in it's own initialization.");
return;
}
ResolveLocal(expr.m_identifier, expr.m_startLine);
}
}
protected object EvaluateVarExpr(AstVarExpr expr)
{
if (HadErrorOrReturn())
{
return(null);
}
if (expr.m_instance == null)
{
object result = null;
bool success = m_environment.Get(expr.m_identifier, out result);
if (!success)
{
m_runtimeError = true;
Lox.Error(expr.m_startLine, "Undeclared identifier \"" + expr.m_identifier.m_identifier + "\"");
return(null);
}
return(result);
}
else
{
object instanceObj = EvaluateExpr(expr.m_instance);
Instance instance = instanceObj as Instance;
if (instance != null)
{
object value;
bool success = instance.TryGetMember(expr.m_identifier.m_identifier, out value);
if (success)
{
return(value);
}
m_runtimeError = true;
Lox.Error(expr.m_startLine, "Undefined member \"" + expr.m_identifier + "\"");
return(null);
}
else
{
m_runtimeError = true;
Lox.Error(expr.m_startLine, "Only class instances can access properties with '.'");
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);
}
}
}
public AstAssignmentExpr(AstVarExpr lhs, AstExpr rhs)
: base(EXPRK.Assignment, lhs.m_startLine)
{
m_lhs = lhs;
m_rhs = rhs;
}
