Re^3: defining variables using my


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Re^3: defining variables using my - subroutines

by kennethk (Abbot)

on Sep 05, 2012 at 17:34 UTC ( [id://991898]=note: print w/replies, xml )

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in reply to Re^2: defining variables using my - subroutines
in thread defining variables using my - subroutines

Under normal usage, they take values not variables. If you run the code

sub add_one {
    my $x = shift;
    $x += 1;
    return $x;
}
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You would not expect the variable you passed in (my $y = add_one($outer_x);) to change value, right? This is a little awkward/contrived, but this is in contrast to more object-oriented frameworks.

Advanced: Of course Perl actually does pass by reference with lvalues bound to @_. But that's probably the best reason for transferring subroutine inputs to locally-scoped variables.

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.