public string visitOperandExpr(Expression.Operand expr)
{
switch (expr.Value.GetName())
{
case "UNARY":
case "BINARY":
return(((Expression)expr.Value).Accept(this));
case "INTEGER":
return("int");
case "STRING":
return("string");
case "VAR_IDENTIFIER":
var ident = (VarIdentifier)expr.Value;
if (!environment.Contains(ident.Name))
{
ErrorWriter.Write(ident, "Cannot operate on uninitalized variable '{0}'", ident.Name);
return(null);
}
return(environment.GetType(ident.Name));
default:
return(null);
}
}
private Expression.Operand operand()
{
current = advance();
if (current.GetName() == "LEFT_PAREN")
{
var opr = new Expression.Operand(expression());
match("RIGHT_PAREN");
return(opr);
}
if (current.GetName() == "IDENTIFIER")
{
return(new Expression.Operand(createIdent(current)));
}
return(new Expression.Operand(current));
}
public object visitOperandExpr(Expression.Operand expr)
{
var value = expr.Value;
switch (value.GetName())
{
case "UNARY":
case "BINARY":
return(((Expression)value).Accept(this));
case "INTEGER":
return(Int32.Parse(((Token)value).Value));
case "VAR_IDENTIFIER":
var ident = (VarIdentifier)value;
return(environment.Get(ident.Name));
default:
return(((Token)value).Value);
}
}
