Parse and validate a comma separated list of strings

[Matt Friedman]

Hi,

I'm new to bison and this list so forgive me if I'm asking something
that has been asked before. I've done quite a bit of reading and
searching and haven't found the answer yet.

My goal is to parse a comma separated list and validate the values
that I find therein. I don't have a problem parsing the list. This is
fairly straightforward.

What I would like to do in addition to parsing the list is to validate
that each value I find in that list is one of a set of strings. That
is, I want to validate that each item in the list is correct.

Each token in the list can be a one or two character uppercase string.
i.e. [A-Z]{1,2}

I'd like the parser to raise an error if the parsed token isn't one of
the ones in the predetermined list. Let's say the predetermined valid
list is: AA,BB,C,DE

If BD is entered this should raise an error.

Is this something that would be done in bison? Or would it be better
to handle this post-parse? Or in another context?

Here's what I have in the parser atm:

itemlist:       CODE    
                {
                        strcat(wordbuf, $1);
                }
                |
                itemlist CODE
                {
                        strcat(wordbuf, ","); strcat(wordbuf, $3);              
                }
                ;

Many thanks,
Matt