Re: Quoting special characters (was: Re: Possible solution for special characters in makefile paths)

[Eli Zaretskii]

> From: Paul Smith <address@hidden>
> Cc: address@hidden
> Date: Sun, 23 Feb 2014 13:44:13 -0500
> 
>   FOO = foo\ bar
> 
>   $(FOO): ; @echo '"$@"' '"$(FOO)"' '"$(addsuffix .txt,$(FOO))"'
> 
> In your suggested implementation what is printed?  As far as I can see
> it will be one of these three (assuming that $@ is "foo bar" as we've
> discussed here):
> 
>   "foo bar" "foo bar" "foo bar.txt"
> or
>   "foo bar" "foo\ bar" "foo\ bar.txt"
> or
>   "foo bar" "foo\ bar" "foo\.txt bar.txt"
> 
> ?

The first, I hope.  But again, let's first find the best way of
expressing such strings in a Makefile, and get to their expansion
after that.  These are two separate issues.

> > > > > Now we come along with the next release of GNU make.  If you want
> > > > "foo\" and "bar" you have to modify your
> > > > > makefile:
> > > > >   FOO = foo\\ bar
> > > > > Right?
> > > 
> > > > It's one possibility, yes.
> > > 
> > > I'd like to hear another one.
> > 
> > Another one is FOO = "foo bar".
> 
> Well, in any event you're still forced to modify the makefile; that's
> what I was getting at.

Then we are in violent agreement.  But changes like that are
inevitable whatever path we choose, I think.  If the Makefiles to be
changed are rare and far in between, I think we are good.

> > That's not my interpretation of the current situation.  My
> > interpretation is that we do have problems, but we ignore them because
> > colons in file names are rare.
> 
> I think that's a very accurate assessment of the situation with colons.
> However, I don't think saying that we've managed to live with the
> problems with colons so it's OK to extend those same problems to
> whitespace, is necessarily the right answer.

My point was that we already use a backslash to quote some characters.

> The fact is that colons ARE rare in filenames.

Not on Windows ;-)

> > > The difference between this and $[ is that (a) backslashes are much more
> > > common than someone using "[" as a make variable, and (b) assigning to
> > > [ can be detected by make and a warning or error generated, so users
> > > know that there is a backward compat problem.  Adding new backslash
> > > quoting leads to silent changes in behavior.
> > 
> > There's a program called [.exe on my disk, did you consider that?
> 
> There's a program called "[" on my disk, too... :-).  But I don't see
> how that conflicts with the make variable $[... ?

You only think about Make variables, but I also consider the
complications with command lines.  Shell-like quoting and escaping has
the advantage that it will never conflict with command lines.