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Re: improving $! usability (using autodie and readline)

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Paul Fenwick
June 23, 2009 00:53
Re: improving $! usability (using autodie and readline)
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G'day Schwern and friends,

Michael G Schwern wrote:

> This might be something autodie can do.  Hmm.

I would *love* to have autodie wrap readline()/<>, but my previous attempts
to do so have been unsuccessful.  It has a prototype, so this *should* work,
but maybe I'm just not trying hard enough.

Having said that, I just tried:

	perl -MO=Deparse -Mautodie=readline -e'while (<STDIN>) { print };'

and got:

	use autodie (split(/,/, 'readline', 0));
	    $^H{'guard Fatal'} = q(ARRAY(0x12d4a60));
	while (&readline(STDIN)) {
	    print $_;
	-e syntax OK

That reveals that it's able to catch readline (so clearly I haven't been
trying hard enough), but it loses its magic ability of setting $_ inside a
while loop.  I would have expected the deparsed output to be:

	while( defined($_ = &readline(STDIN) ) ) {
	    print $_;

While one could argue that's a bug, fixing for newer versions of Perl won't
help the existing 5.8/5.10 install base upon which autodie presently works.
 If someone can give me pure-perl magic that allows me to detect if
readline() is being called inside a while loop, then I'd appreciate it, as I
can't think of any way off the top of my head.



Paul Fenwick <> |
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