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Consider the following:

use strict; use warnings; printSomething('Hello, world.'); printSomething(); sub printSomething { my $string = shift || 'Nothing was sent.'; print $string, "\n"; }

First output:

Hello, world.

Second output:

Nothing was sent.

In subroutines, shift takes the first element off @_. In the case above, $string is initialized with whatever is sent to the subroutine. However, if nothing is sent, $string is initialized with 'Nothing was sent.' This is because of the logical or operation in Perl. If the first disjunct (shift) evaluates to true, then Perl stops there, since the overall express is true. However if the first disjunct evaluates to false (nothing to shift), Perl moves to the second disjunct. Thus, printSomething() prints Nothing was sent. Here's another way to 'say' this: the variable $string equals either what was sent to the subroutine or the string 'Nothing was sent.'


In reply to Re: shift and logical or by Kenosis
in thread shift and logical or by jonagondos

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