[antlr-interest] antlr v3 C target EOF PUSHSTREAM

[Jim Idle]

They will never change now I would think.]



Jim



*From:* Rampon Jerome [mailto:ramponjerome at yahoo.fr]
*Sent:* Thursday, January 12, 2012 2:55 PM
*To:* Jim Idle; antlr-interest at antlr.org
*Cc:* Gavin Lambert
*Subject:* Re : [antlr-interest] antlr v3 C target EOF PUSHSTREAM





Hi Jim, Gavin



Thanks for your quick answers.

I agree with your feedbacks to overload nextToken in C interface

but just two remarks:



-this obliges to redefine nextToken, nextTokenStr and emit

from antlr3lexer.c as they are all static. Not so good in term of
maintenance

for the grammar.



-In my case, I just need to pop some data structure when

popstream is invoked in nextToken on EOF

(DS were pushed just before calling PUSHSTREAM)

I originally had in mind some simpler redefinition if nextToken from
antlr3lexer

was not static as ... would avoid any maintenance work on nextToken,
nextTokenStr and emit

redefinition ...



Init

lexer->rec->state->tokSource->nextToken = myNextToken



and

myNextToken (...tokSource) ...

  lxr = (pANTLR3_LEXER) tokSource->super;
  state = lxr ? lxr->rec->state : NULL;
  stackSizeInit = (state && (state->streams)) ?
state->streams->size(state->streams) : 0;

  tok = nextToken ... /* original */

  stackSize = (state && (state->streams)) ?
state->streams->size(state->streams) : 0;

  while (stackSizeInit-- > stackSize)

     popMyDataStructure;

return tok;



Jerome


------------------------------

*De :* Jim Idle <jimi at temporal-wave.com>
*À :* antlr-interest at antlr.org
*Envoyé le :* Jeudi 12 Janvier 2012 0h00
*Objet :* Re: [antlr-interest] antlr v3 C target EOF PUSHSTREAM


You can override nexttoken - I have explained how to do it on here before,
so you should find it antlr.markmail.org  basically you make a copy of the
functions you need and install your own pointers.

Jim


At 11:29 12/01/2012, Rampon Jerome wrote:
>I do not see how to do a similar job with C target as nextToken
>redefinition is not possible

It's been a while since I played with the C target, but IIRC most of the
"methods" (probably including nextToken) are defined as function pointers
within the structure data.  So you should be able to subclass the lexer and
reassign the pointer to your override method -- you just have to handle the
recasting and base pointer preservation yourself.


> -----Original Message-----
> From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-
> bounces at antlr.org] On Behalf Of Rampon Jerome
> Sent: Wednesday, January 11, 2012 2:30 PM
> To: antlr-interest at antlr.org
> Subject: [antlr-interest] antlr v3 C target EOF PUSHSTREAM
>
>
>
>
> Hi,
>
>
> I already used PUSHSTREAM macro on C target to switch input streams
> with v3.
>
> I did similar work on Java with personal stack of stream and nextToken
> redefinition (someway close to some example found later in antlr wiki
> pages)
>
> I need to manipulate(push/pop) some additional data structures all
> along the stack of input streams.
> It is simple to add in my own stack of stream with extension and
> nextToken redefinition in Java.
>
> I do not see how to do a similar job with C target as nextToken
> redefinition is not possible
>
> Is there one way to redefine EOF token to add specific actions ? or
> anything that would permit expected
>
> actions ...
>
> I just want to manage data structures in a parallel stack and pop on
> EOF in v3 in C !!!
>
> Thanks for any idea
>
>
> Jerome
>
> List: http://www.antlr.org/mailman/listinfo/antlr-interest
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