Re: a MooseX Q that's driving me up the wall :)

sub f {
   'xxx' =~ /(.*)/;
   print("$_[0]\n");
}

'aaa' =~ /(.*)/;  f($1);    # xxx
'aaa' =~ /(.*)/;  f("$1");  # aaa
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Perl passes arguments by reference, not by value. You are passing a global variable, and the global variable gets changed the by the called function before the argument is used. Passing a copy of the global avoids the problem.

Comment on Re: a MooseX Q that's driving me up the wall :) Download Code

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Re^2: a MooseX Q that's driving me up the wall :) by tj_thompson (Monk) on Dec 03, 2010 at 17:06 UTC
That makes sense. And quoting the global like "$1" would result in a literal string being passed, taking the global out of the result. Thanks!	[reply]
Re^3: a MooseX Q that's driving me up the wall :) by ikegami (Patriarch) on Dec 03, 2010 at 17:14 UTC
A string literal is a piece of code, so it's not a string literal being passed. The string literal, however, does create a new string. That's what's being passed.	[reply]
Re^4: a MooseX Q that's driving me up the wall :) by tj_thompson (Monk) on Dec 03, 2010 at 18:47 UTC
Good point on the string. Thank you very much for the insight, I feel far better now that I understand what was going on. Upon introspection, it should have been fairly obvious now that I think about it.	[reply]
Re^2: a MooseX Q that's driving me up the wall :) by Anonymous Monk on Dec 03, 2010 at 17:11 UTC
Huh, I thought that MooseX::Declare just copied to the method's args. But it aliases them instead, like they're aliased in @_? That's pretty cool.	[reply]