leland@cs (12/07/90)
I have an application that requires two discrete uses of both lex and yacc. Since both lex and yacc have hardcoded names (all with the 'yy' prefix) for a whole bunch of global symbols, there is an immediate problem: somehow the two sets must be hidden from each other and distinguished for any other code that accesses them. I've tried this kludge: create a header file that re-#define's all the names 'yyfoo' in lex/yacc set #1 to be named, say, set1yyfoo, and all those in set #2 to be named set2yyfoo. This has worked for me in the past, but won't in this particular instance because the generated code includes calls to yyless() and yywrap(), which are in the LEX library (-ll), the contents of which I cannot rename. So that doesn't work. I've also investigated GNU's replacements for these programs, flex and bison. I haven't gotten to the bison documentation yet, but a quick look at the flex man page implies that these programs still have the hardcoded global symbol names. Flex eliminates the need for the external library, however, so this may solve my problem. But it's still a horrible kludge, and it would require that others to whom I distribute the software maintain flex and/or bison. I'm looking for something better. I may be able to use some special loader options to 'hide' the yy* symbols when compiling the object modules that contain them, but the procedure for doing is not obvious nor it is standardized across loader versions. Has anybody listening gotten into this before? Can you offer any suggestions? Thanks for whatever you may know. It is difficult to accept that, considering how long these programs have been around, none of the implementers ever thought to make these globals static or to add a command-line option to rename them. Leland Woodbury -- ARPANET/INTERNET: leland@cs.columbia.edu USENET: ...!columbia!cs.columbia.edu!leland BITNET: leland%cs.columbia.edu@cuvmb USMAIL: Columbia Univ., 457 CS, 500 W. 120 St., NYC 10027-6699