Is there a file include mechanism for YACC files?

Question

I have three programs that are currently using YACC files to do configuration file parsing. For simplicity, they all read the same configuration file, however, they each respond to keys/values uniquely (so the same .y file can't be used for more than 1 program). It would be nice not to have to repeat the %token declarations for each one - if I want to add one token, I have to change 3 files? What year is it??

These methods aren't working or are giving me issues:

1. The C preprocessor is obviously run AFTER we YACC the file, so #include for a #define or other macro will not work.

2. I've tried to script up something similar using sed:

REPLACE_DATA=$(cat <file>)

NEW_FILE=<file>.tmp

sed 's/$PLACEHOLDER/$REPLACE_DATA/g' <file> > $NEW_FILE

However it seems that it's stripping my newlines in REPLACE_DATA and then not replacing instances of $PLACEHOLDER instead of replacing the contents of the variables PLACEHOLDER.

Is there a real include mechanism in YACC, or are there other solutions I'm missing? This is a maintenance nightmare and I'm hoping someone else has run into a similar situation. Thanks in advance.

Answer 1

here's a sed version from http://www.grymoire.com/Unix/Sed.html#uh-37

#!/bin/sh
# watch out for a '/' in the parameter
# use alternate search delimiter
sed -e '\_#INCLUDE <'"$1"'>_{
    r '"$1"'
    d
}'

But traditionally, we used the m4 preprocessor before yacc.