Re: RFI: Trailing blanks

[akim]

On Fri, Aug 17, 2001 at 11:50:24PM +0100, Gary V. Vaughan wrote:
> On Friday 17 August 2001 4:49 pm, Akim Demaille wrote:
> > Typically, one can observe that the Autotest snippet contain useless
> > multiple empty lines, which are to be killed, while those in the test
> > values have to be kept.
> >
> > So I would like to remove that --normalize, completely replaced with
> > @""@.  Does it sound OK to everybody?

:( :( :(

That's not the end of the story, unfortunately...

Well, consider the following problem: sometimes we want to output
user supplied strings with say echo, whatever.  But then, we have to
escape some characters when embeded in double quotes.

So... guess what...

Something like AC_MSG_RESULT(@""@) outputs @\"\"@, not @""@.  So the
quadrigraph is not recognized, and not replaced.  I'm not in favor of
also replacing @\"\"@, but just because it frightens me a bit.  If someone
is convinced this is OK, then I'm OK.

So we are looking for specially non special characters. @address@hidden

> This solution looks good to me.  However, I also wonder whether it would be 
> more transparent if the `smashing' code were to know about here documents
> and test files?  Blank lines in such strings could be left untouched.

i very much agree!  That's definitely what I would like most, but this
means you need some form of `eval' in M4 which performs the expansion
as if you were at the top level, and after this expansion, add those
@""@ at the end of each line.

And one such `eval' is almost impossible to write.  Well, you can,
but then what is it semantics wrt side effects?  wrap, define, divert
and so on.

I once dreamt of it, but I can't see how it would fit with the semantics
of M4. 

Another possibility would be sort of autom4te pragma lines

#smash: off
some


multiple


empty lines
#smash: on



Heeeeeeeeeeelp!