Hi Akim and Gary,
On Thu, Feb 10, 2005 at 01:55:16PM +0100, Akim Demaille wrote:
> >>> "Stepan" == Stepan Kasal <[EMAIL PROTECTED]> writes:
> > + + We need a way to ask for one level of expansion; this is somewhat
> > + similar, but not identical, to `defn'. For example:
> > + expandonce(`macro(a, b, c)')
> I'm not sure I agree with the "once". You just apply the regular
> evaluation rules, and return the result quoted. But if foo is defined
> to bar, and bar to baz, then eval([foo]) should definitely return [baz].
I believe this can be implemented as
define([m4_quote], [[$1]])
the parameter is fully evaluated and then quoted. Unless the expansion
contains an unmatched quote, everything works.
What we need is exactly the ``once'' feature.
After an irc discussion with Gary, his proposal has landed as `qindir' to
the TODO file in the CVS head. Let me cite it:
+ Implement qindir. Like indir, except that the result of the macro call
is not expanded. Because the input stack might contain a file or a
string, it is probably best achieved by making note that the TOS input
should be copied rather than rescanned.
$ echo "a'b" > f
$ m4
define(a,z)dnl
include(f)dnl
z'b
indir(`include', f)dnl
z'b
qindir(`include', f)dnl
a'b
define(b,NONO)dnl
patsubst(qindir(`include', f), b, x)
z'x
[Note to Gary: I slightly modified the example, and checked in to the CVS.]
On Thu, Feb 10, 2005 at 03:54:45PM +0000, Gary V. Vaughan wrote:
> Akim Demaille wrote:
> > Rather I think we should have another set of builtins.
>
> As in qregexp, qinclude, qifelse and so on? [...]
I think Akim was not aware about the qindir proposal when he wrote this.
> > While you're at it, the new regexp
> > builtins should drop BRE dead, and use ERE too.
Well, as it doesn't look as if we were adding an alternate set of builtins,
I believe we could take this as a proposal to implement `eregexp' and
`epatsubst'.
Happy hacking,
Stepan
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