Re: for loops in C style

[Ilyes Gouta]

OK, got it.

One has just to define fexpr as:

fexpr:
    ';'           { action1(); }
|   expr ';'    { action2(); }

and to redefine for_stmt as:

for_stmt:
   for (assignment expr assignment) block
;

to get the right behavior. :)

Thanks again, guys!

Best regards,
Ilyes Gouta.

On Fri, Feb 29, 2008 at 10:23 AM, Ilyes Gouta <address@hidden> wrote:
> Hi!
>
>  Thanks for your help.
>
>  If I setup a new fexpr (and a new fassignment) that would accept
>  nothing or expression, i.e:
>
>  fexpr:
>     | expr;
>
>  for_stmt:
>     for (fassignment; fexpr; fassignment) block
>
>  How can I define an action that would be triggered only for the empty
>  expressions? (I have to differentiate between the two cases since they
>  won't have a common action)
>
>  The only meaningful way, I found on the net to handle this, is this one:
>  http://www.cs.uaf.edu/2007/fall/cs631/Cyacc.y
>
>  Basically what it's done is enumerating all the possibilities for the
>  construction of the for loop. Is it the only way do things clearly and
>  properly?
>
>  Best regards,
>  Ilyes Gouta.
>
>
>
>  On Thu, Feb 28, 2008 at 9:59 PM, Hans Aberg <address@hidden> wrote:
>  > On 28 Feb 2008, at 15:16, Ilyes Gouta wrote:
>  >
>  >  > I'm writing a small grammar for a very simplified C language. My goal
>  >  > is to produce an AST once a script file is parsed by the flex/bison
>  >  > tools. I got almost everything working nicely, except for the C style
>  >  > for loops.
>  >  ...
>  >
>  > >  How one would modify the grammar to take into
>  >  > account such a scenario?
>  >  >
>  >  > Any ideas?
>  >
>  >  There is a Yaccable grammar of C++ - you might check that out
>  >    http://www.parashift.com/c++-faq-lite/compiler-
>  >  dependencies.html#faq-38.11
>  >
>  >    Hans Aberg
>  >
>  >
>  >
>