Re: sub that sets $

In a while expression, the automatic setting of $_ happens only when the content of the parentheses after the while is an expression of the form <HANDLE>. You'll need something like

while ( $_ = $reader->chunk ) {
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the lowliest monk

Comment on Re: sub that sets $_ Download Code

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Re^2: sub that sets $_ by ikegami (Patriarch) on Jun 28, 2005 at 15:19 UTC
Don't forget to use `local $_` before `while ( $_ = $reader->chunk ) {`, or you might clobber something without even realizing it. For example, the following snippet replaces the content of @array with false values because $_ is (in turn) a reference to each element of @array: `foreach (@array) { ... my $reader = ...; ... while ($_ = $reader->chunk) { ... } ... }` [download] The following dies with the run-time error "Modification of a read-only value attempted": `for ('a', 'b') { ... my $reader = ...; ... while ($_ = $reader->chunk) { ... } ... }` [download]	[reply] [d/l] [select]
Re^3: sub that sets $_ by tlm (Prior) on Jun 28, 2005 at 15:32 UTC
Yes. Actually, nobull recently made the case for localizing `*_` instead of `$_`, although this added precaution is probably more important for functions and methods in modules than for top-level code. the lowliest monk	[reply]
Re^2: sub that sets $_ by holli (Abbot) on Jun 28, 2005 at 10:45 UTC
Well, that circumvents the whole convenience. Sad. I believed that would be possible. Thanks for your response.	[reply]
Re^3: sub that sets $_ by blazar (Canon) on Jun 28, 2005 at 11:03 UTC
Well, it may be possible with a tied hash. Would it be worth, though? (except for fun, that is - I've never played with this "kinda things" myself, but I'm tempted!) UPDATE:as per revdiablo's remark, s/hash/filehandle/. Just a typo, and only because tied hashes are IMHO the kind of tied objects one most often can hear about...	[reply]