private SyntaxNode ParseAssignmentExpression()
{
SyntaxNode expr = ParseBinaryExpression();
if (Match(TokenType.Equal))
{
Token equals = Previous();
SyntaxNode value = ParseAssignmentExpression();
if (expr is VariableExpression)
{
Token name = ((VariableExpression)expr).Name;
return(new AssignmentExpression(name, value));
}
else if (expr is GetExpression)
{
GetExpression get = (GetExpression)expr;
return(new SetExpression(get.Object, get.Name, value));
}
Error(equals, "Invalid Assignment Target");
}
return(expr);
}
private object EvaluateGetExpression(GetExpression expr)
{
var obj = Evaluate(expr.Object);
if (obj is LoxInstance)
{
return(((LoxInstance)obj).Get(expr.Name));
}
throw new RuntimeError(expr.Name, "Only instances have properties");
}
private SyntaxNode ParseCallExpression()
{
SyntaxNode expr = ParsePrimaryExpression();
while (true)
{
if (Match(TokenType.LeftParen))
{
expr = ParseFinishCall(expr);
}
else if (Match(TokenType.Dot))
{
Consume(TokenType.Identifier, "Expect property name after '.'");
Token name = Previous();
expr = new GetExpression(expr, name);
}
else
{
break;
}
}
return(expr);
}
