Re: concatenating string into $$

[Hans Aberg]

At 14:50 -0800 2004/02/27, Tom Jackson wrote:
>On Fri, 2004-02-27 at 10:53, Hans Aberg wrote:
>> You can write it as you suggest, in one single statement:
>>   ifcmd:
>>       IFCMD ARGUMENT ENDCMD statements ENDIF {...}
>
>The above does work, and I had tried it, the problem is I can't figure
>out a way (good or bad) to print out the result. Here is what I am doing
>now, but it doesn't validate the if:
>
>(I've looked at gcc java's parse.y, a very complex example. It looks
>like it stores everything in various structures. In my case I wouldn't
>mind reading and validating an entire file at a time. Are there any
>examples less advanced?
>I also tried
>sprintf($$,"some string %s", $2)... Not sure if this worked or not.
>)

The problem is that you do not tell how you hook up your lexer: A lot of
people forget copying the token that the Flex lexer identifies in its
buffer. A single Bison parser rule will typically call the lexer several
times before proceeding to the action. Thus, without copying, one gets
funny answers.

If all your tokens and variables make a printout, and your lexer is
correctly hooked up, you may simply write
   ifcmd:
       IFCMD ARGUMENT ENDCMD statements ENDIF {
         sprintf($$,"if %s then %s", $2, $4);
       }
And so forth.

You might benefit by using Bison's debugging features (see manual).

  Hans Aberg