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Postings from July 2012
On Wed, Jul 18, 2012 at 4:35 PM, Paul Johnson <paul@pjcj.net> wrote:
> On Tue, Jul 17, 2012 at 11:44:35PM -0700, l.mai@web.de wrote:
>
>> % perl -we '"qwertasd"'
>> Useless use of a constant ("qwertasd") in void context at -e line 1.
>>
>> % perl -we '"dsatrewq"'
>>
>>
>> Any string starting with "di", "ds", or "ig" is exempt from "void context"
>> warnings. I can't find any documentation for this misfeature. It should be
>> removed from the interpreter.
>
>
> It's not really a misfeature. It's more of an old feature. The code
> explains why it's there:
>
> op.c:1473
> /* perl4's way of mixing documentation and code
> (before the invention of POD) was based on a
> trick to mix nroff and perl code. The trick was
> built upon these three nroff macros being used in
> void context. The pink camel has the details in
> the script wrapman near page 319. */
>
> As far as documentation is concerned, I suppose that it wouldn't be a
> bad thing to make a note of this somewhere.
>
> As far as removing it is concerned, I presume that no one is writing new
> code in this way, and probably hasn't for a few years. So the removal
> is a trade-off between a slight standardisation and simplification and
> breaking backwards compatibility with some perl4 era programs.
>
> I would side with keeping backwards compatibility.
Considering this is a warning that has to be enabled explicitly, and
that we're talking about perl 4 compatibility here, I wouldn't care
too much about such a minor break of backwards compatibility. I'd be
surprised if this was the first time in the past 18 years that such a
thing happened.
Leon
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