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Re: Use of uninitialized value in pattern match (m//)

by tobyink (Abbot)
on May 23, 2012 at 22:38 UTC ( #972120=note: print w/replies, xml ) Need Help??

in reply to Use of uninitialized value in pattern match (m//)

It's the elsif condition that's triggering it. (The line numbers reported in Perl's error messages... well, there is a logic to them, but it can seem impenetrable at times. In multi-line constructs the line number reported is sometimes several lines away from where a human being would judge the error to have occurred.)

When you use a pattern match (like /^\s*$/) you need to tell it what variable to test. e.g.:

$str =~ /^\s*$/

If you do not tell it what variable to test, then Perl will test the special variable called $_. In your case, $_ appears to be undefined. Hence the message.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

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