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Pre-RFC: syntax for quote-words-arrayref
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From:
Neil Bowers
Date:
May 31, 2022 07:41
Subject:
Pre-RFC: syntax for quote-words-arrayref
Message ID:
0fb222b4-2934-4f3d-91e8-e61d82e5adf5@Spark
In early March last year, I proposed[1] new syntax for "quote words arrayref",
so that the following:
   $a = [qw/ a b c /];
could be replaced with:
   $a = qa[ a b c ];
(or maybe qwa[] or qaw[]). There are modules for this on CPAN - see my original post for references[1].
Roughly 36% of CPAN distributions use that idiom at least once.
This seemed to be well received. Until ...
Rik said why not go all-in and spec out a new swiss army chainsaw quoter,
which can take options, so, using qz as an example:
   $a = qz:d[ a b c ];   # 'd' says delimiter determines type, arrayref
   $h = qz:d{ ...  };   # hashref
   @a = qz:d( a b c );   # list, i.e. like qw( ... )
But also:
   $a = qz:id[ a $b c ];  # i: interpolative
   $a = qz:dx[
       a  # with a comment
       b
       c  # another comment
     ];
At least two people liked the comments and interpolation.
I find myself wishing we had qa[] on a regular basis. I've never wished
for an equivalent for hashrefs, or for comments, or interpolation.
The => already gives us barewords on the left;
do people really want it for the values as well?
Enough people?
The motivation for qa[] is that it's easier to read, and less to type.
The chainsaw undoes that saving, plus now we have two ways to quote
basic word lists.
I couldn't see myself using it, and it's more confusing looking for the
casual reader/programmer than the syntax I was originally trying to improve.
I want to make life easier for the 38% of CPAN authors, not the some
small number of very experienced Perl programmers.
So really, I just want qa[], but if I can't get that past the pesky PSC,
then we could consider having the options of Rik's idea always turned on,
and we name it qs, or the smart quote operator[2]?
   $a = qs[ a b c ];
   @a = qs( a b c );
   %h = qs( a 1 b 2 c 3 );
   $h = qs{ a 1 b 2 c 3 };
You wouldn't be allowed to use anything other than [], (), and {} as quote chars.
We could make => a no-op, so you can at least make it look like a hash:
   $h = qs{ a => 1 b => 2 c => 3 };
That might cause more confusion than benefit though, so probably not.
It would interpolate other scalars, arrays, and hashes,
and would allow inline comments
   $w = qs[
        zork     # blah blah
        xyzzy     # plugh plugh
        $favourite
        @defaults
      ];
But, you say, what if people want the literal '@defaults' in there?
I think things that are different should look different,
and if you want that literally, then you should see '@defaults'.
Really, I just want qa[]. I see evidence for the value of that.
I don't see evidence for qs, but that doesn't mean that people wouldn't use it.
Neil
[1]Â https://www.nntp.perl.org/group/perl.perl5.porters/2021/03/msg259214.html
[2] We should never name anything "smart <thing>" again, of course.
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Pre-RFC: syntax for quote-words-arrayref
by Neil Bowers