Common difficulty with Flex++

Question

Note: Someone with over 1500 rep.. please add flex++ and bison++ as tags :).

Seems like people all over the Internet have been getting the following errors with Flex++:

scanner.l:1: bad character: %
scanner.l:1: unknown error processing section 1

This happens on any example I give Flex++. The version I have is from here and I have tried the exact examples on that page and I still get these errors. I've tried on Linux and Mac and have completely run out of ideas!

Seems like Flex++ is a name for an old virus out there too so it's particularly hard getting useful discussion!

EDIT:

Here's an example that produces the above error (first few lines from example taken from the link above):

%name CalcScanner
%define IOSTREAM
%define LEX_PARAM YY_CalcParser_STYPE *val, YY_CalcParser_LTYPE *loc
%define MEMBERS public: int line, column;                                                                                               
%define CONSTRUCTOR_INIT : line(1), column(1)

%header{
#include<sstream>
#include "parser.h"
%}

Any help would be more than fantastic.

EDIT 2: Please can people not edit this post by putting the 'flex' tag in? Flex would be what I would use to tag but Flex is also an Adobe technology - it's NOT the tool I am using. The flex tag on SO is for the Adobe product (hence the logo on the tag). Thank you :).

You're correct that `flex` is the wrong tag. There's `gnu-flex` for the lexer/parser-generator. — Ben Voigt, Jul 09 '11 at 23:48
@Ben: Which is an odd tag in itself; the flex we're talking about here is non-GNU. See http://www.gnu.org/software/flex/ — eriktous, Jul 10 '11 at 15:25
@erik: Hey, I didn't create the tag. Is there another flex application that is GNU? — Ben Voigt, Jul 10 '11 at 21:37
@Ben: Haha, I know you didn't create it (well, technically, I didn't know that, but I assumed it); it was just a random observation, so to speak. And no, there is no GNU flex (at least not that I know of). — eriktous, Jul 10 '11 at 22:13

score 2 · Answer 1 · answered Jul 09 '11 at 23:09

2

Check your line-endings? CR+LF vs NL might make a difference here.

answered Jul 09 '11 at 23:09

Ben Voigt

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Good idea but unfortunately, doesn't seem to be the case. Also, it complains about the very first character in the file which is confusing :s! – ale Jul 09 '11 at 23:42
If the line endings were wrong, then flex++ would consider the entire file to be in line 1. It could then be the second instance of `%` it's complaining about. Can you put just the first line into a file by itself and see if the error messages are the same? – Ben Voigt Jul 09 '11 at 23:44
Thanks for the tips Ben. Firstly, changing the line endings doesn't fix the problem... I've tried both types by switching endings, saving as a new file and running it on the new file. Putting the first line into a file of its own produces this: – ale Jul 09 '11 at 23:58
`scanner2.l:1: bad character: % scanner2.l:1: unknown error processing section 1 scanner2.l:1: unknown error processing section 1 scanner2.l:1: unknown error processing section 1 scanner2.l:1: premature EOF` – ale Jul 09 '11 at 23:59

Common difficulty with Flex++

1 Answers1