YACC parser & conditional compilation directives

I'm writing a kind of assembler translator, the grammar is perfectly
suitable for Yacc, but my problem is the conditional compilation
directives. For example, in the following source first and third
sections must be bypassed:


DEFINE a,2


IF a==1
      ... Do one thing ...
ELSE
    .IF a==2
        ... Do another thing
    .ELSE
        ... Do yet another thing
    .ENDIF
ENDIF


etc.


(All directives start with dot)


Of course, I could use some kind of hack in lexer, that would recognize
IFs, .ELSEs, .ENDIFs etc. and act accordindly, but I want to know
if there is a _nice_ way of skipping the conditioned out source ?
Besides, the conditional expression may be quite complex and I would have
problems with its parsing, had I used the hack.


Vadim
[Yacc doesn't handle this kind of two-level grammar at all well. You need
either a two-pass system or some gross lexical hacks. -John]
--

Return to the comp.compilers page.
Search the comp.compilers archives again.