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One can predeclare subroutines with
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| 2 |
sub name; # command and use before implementation appears
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| 3 |
One can generate subroutines using EVAL or anonymously as in:
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| 4 |
sub newprint {
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my $x = shift;
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return { my $y=shift; print "$x, $y!\n"; }; # return anonymous subroutine
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}
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$h = newprint("Howdy"); # $h Holds anonymous subroutine
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&$h("World"); # Calls anonymous subroutine and we get
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| 8 |
Howdy, World! printed
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| 9 |
Note the $x in anonymous subroutine is private and retains value Howdy in $h even when you call newprint again with
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| 10 |
$g= newprint("Greetings"); # $g has separate instance of $x
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