Multiple flex/bison parsers

Question

What is the best way to handle multiple Flex/Bison parsers inside a project?

I wrote a parser and now I need a second one in the same project. So far in the third section of parser1.y I inserted the main(..) method and called yyparse from there.

What I want to obtain is having two different parsers (parser1.y and parser2.y) and be able to use them from an external function (let's assume main in main.cpp).

Which precautions should I use to export yyparse functions outside .y files and how should I handle two parsers?

PS. I'm using g++ to compile but not the C++ versions of Flex and Bison and I would like to keep it this way (so avoiding encapsulating the parser inside an object).

Answer 1

In addition to Leffler's answer, I'd like to provide another approach here:

In the .lex file you could use %option prefix="PREFIX", and in the .y file you could use %define api.prefix PREFIX, which does the same thing as passing -p PREFIX to Bison and -P PREFIX to Flex.

Notice after the overriding of the default prefix yy, you can access internal names via BOTH the original yy* and your overridden PREFIX*, while obviously for external names you MUST use your PREFIX* to access them.

Answer 2

Note that Bison provides the '-p zz' option to prefix symbols with 'zz' instead of 'yy'.

Similarly, Flex provides the '-P zz' option to prefix symbols with 'zz' instead of 'yy'. It uses '-p' for performance reporting. 'Tis a pity they are not consistent with each other.