Re: Flex/Bison/ANTLR question... alternative tools for translation?

On 15 Mar 2005 01:42:26 -0500 in comp.compilers, rgaupsas
<elikon@cox.net> wrote:


>I'm working on a translator whereby the input grammar is poorly
>defined; a lot is contextually dependent. I've gotten pretty far with
>Flex/Bison, making heavy use of lexical tie-ins to deal with
>this. However I have some cases, and expect to see more, which Bison
>handles poorly, e.g.:
>
> WK COLOR COLOR ... COLOR NAME PARAM = NUMBER
>
>The problem is that syntactically NAME and PARAM are indistinguishable
>from COLOR (both are alpha numeric of the same form), so the following
>form will not work (note Bflag sets the start_state in Flex).


Some lexical examples would help to understand your problem better:
you may be parsing non-terminal and terminal COLORs, etc. as if they
are the same type of token; they should not be, but it's hard to tell.
Which of these presumably syntactic elements are non-/terminals? If
you have a non-terminal COLOR, shouldn't you recognize it lexically by
looking up a list of currently valid colours, which may be modified by
defining a new colour name and value, if I understand some of your
intentions correctly?


--
Thanks. Take care, Brian Inglis Calgary, Alberta, Canada


Brian.Inglis@CSi.com (Brian[dot]Inglis{at}SystematicSW[dot]ab[dot]ca)
        fake address use address above to reply

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