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Postings from November 2019
On Thu, Nov 28, 2019 at 12:07 PM Dave Mitchell <davem@iabyn.com> wrote:
> =head2 Allow a shortcut for a 'default' default value
>
> allow $foo? as a shortcut for $foo=undef
> and $? as a shortcut for $=
>
> Similarly for reference aliases,
> \$s? becomes a shortcut for \$s = undef,
> \@a? becomes a shortcut for \@a = [],
> \%h? becomes a shortcut for \%h = {},
>
> At the same time, ban the existing legal syntax '$=' which means an
> optional placeholder, and allow only the new '$?'. This would make things
> more consistent, as '$foo=' is currently illegal. Also, I find a bare
> trailing equals sign ugly, and it could potentially clash with future
> syntax which might be added to the end of a parameter.
>
While I don't disagree with this from a design standpoint, I would point
out that of the breaking changes that have been proposed, this is the only
one that could make it difficult to write signatures reusable back to the
5.20 versions in the common case. You could use '$dummy = undef' in both
cases, but it might be nice to continue allowing trailing = and maybe allow
it to go through a deprecation cycle later.
-Dan
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