Re^2: Scalar refs, aliasing, and recursion weirdness.


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Re^2: Scalar refs, aliasing, and recursion weirdness.

by BrowserUk (Patriarch)

on Feb 04, 2005 at 23:33 UTC ( [id://428246]=note: print w/replies, xml )

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in reply to Re: Scalar refs, aliasing, and recursion weirdness.
in thread Scalar refs, aliasing, and recursion weirdness.

I think you may have hit the nail on the head.

It would appear that if you modify an lvalue ref, it gets converted to a normal scalar before the modification.

Which is annoying and counter-intuative (to me anyway), but maybe work that would be involved in allowing the underlying scalar to be modified through a substring of an lvalue ref is too complicated?

Maybe I will have to code my own lvalue-ref-on-steroids to achieve my purpose?

Examine what is said, not who speaks.

Silence betokens consent.

Love the truth but pardon error.

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Re^3: Scalar refs, aliasing, and recursion weirdness.
by !1 (Hermit) on Feb 04, 2005 at 23:38 UTC

Even better example:

#! perl -slw
use strict;

sub recurse {
    print ">> '${ $_[ 0 ] }'";
    (my $depth=$_[1])--;
    if ($depth) {
        recurse( \ substr( ${ $_[ 0 ] }, 1, -1 ), $depth );
    }        
    else {
        ${$_[0]} = "XX";
    }        
    print "<< '${ $_[ 0 ] }'";
    return;
}

my $str = 'abcdefghi';

recurse \$str, 3;
print $str;

recurse \$str, 2;
print $str;

__END__
>> 'abcdefghi'
>> 'bcdefgh'
>> 'cdefg'
<< 'XX'
<< 'bcdefgh'
<< 'abcdefghi'
abcdefghi
>> 'abcdefghi'
>> 'bcdefgh'
<< 'XXi'
<< 'aXXi'
aXXi
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