Re: #line format

[Paul Eggert]

> Cc: Bison Help <address@hidden>
> From: Akim Demaille <address@hidden>
> Date: 10 Apr 2002 19:52:19 +0200
> 
> For some time, I have believed that:
> 
> ---------- foo.c ---------
> 
> #line 1 "foo.y"
> #error "This is reported in line 1 of foo.y"
> #line 45
> #error "This is reported in line 45 of foo.c"
> 
> -------------------------
> 
> But it turns out that GCC, seeing a plain `#line NUM' with no FILE
> complains in the current file, i.e., here, foo.y.

I think GCC is correct here.  Sun C is the same.


> My problem with
> 
>         #line 45 "foo.c"
> 
> is that the name of the file is coded inside, which is very painful
> when you mv the file.

Sorry, I'm a bit lost.  Why do you want the file to refer to itself?

Can't you solve the problem by having the #line directive refer
instead to some template file like bison.simple, in a well-known
location?  That's what Bison 1.35 does.


> Is there something available in the set of #line that would comply
> these requirements?

Sorry, not that I can think of.  Once you change the value of __FILE__
I don't see any way to refer to the previous value.

Perhaps you can rewrite the file so that the #line 45 stuff all
appears before the #line 1 "foo.y" stuff.  That might solve the
problem.  (But clearly I don't understand the problem, so....)