thanks very much, this does what i'd like it to do, and if i compare it to my orginal function it even takes care of the 'numeric 0' vs. 'empty string' inequality. 
my @vals =        (undef,           0,        '0', 'aap', 1, 't','');
my @expl =        ('undef','numeric 0','string 0', 'string "aap"', 'nu
+mber 1', 'string t','empty string');

my ($i,$j);

for ($i=0; $i <= scalar(@vals-1); $i++) {
    for ($j=0; $j <= scalar(@vals-1); $j++) {
        # equals 1
        print "equals_org '$expl[$i]'\t'$expl[$j]'\t" . equals_org($va
+ls[$i],$vals[$j]) . "\n";
        print "equals_new '$expl[$i]'\t'$expl[$j]'\t" . equals_new($va
+ls[$i],$vals[$j]) . "\n";
        print "--\n";
    }
}

sub equals_org {
    my ($val1, $val2) = @_;

    # first test for undef-ness
    if ( ! defined $val1 || ! defined $val2 ) {
        return 1 if (! defined $val1 && ! defined $val2 );
        return undef; #case one is undef, other is def
    }
    # have to do next line this because strings evaluate to 0 in == co
+ntext ...
    if ( ! $val1  && ! $val2 ) {
        # then test for ""-ness
        return 1 if ( ($val1 eq "") && ($val2 eq "") );
        return undef if ( $val1 eq "" || $val1 eq "" );  
        #case one is "" other is 0
        # then test for 0-ness 
        return 1 if ( ($val1 == 0) && ($val2 == 0) );
    }
    # then test for equality using 'eq'
    return 1 if ( $val1 eq $val2 );
    # then test for equality using '=='
    if ( int($val1) && int($val2) ) {
        # all other number cases are already covered by
        # above tests (eg. both 0, or both the same string)
        # this merely takes care of cases like:
        #   1000.0000 == 1000
        return 1 if ( $val1 == $val2 );
    }
    # couldn't find any, so i guess they are not equal
    return undef;
}

sub equals_new {
    my ($lhs, $rhs) = @_;
    
    #False if mix of defined and undef
    return 0 if defined $lhs != defined $rhs;
    
    # True if both undef
    return 1 if ! defined $lhs && ! defined $rhs;
    
    # False if different as numbers
    no warnings "numeric";
    return 0 if (0 + $lhs) != (0 + $rhs);
    
    # False if different as strings
    return 0 if ('' . $lhs) ne ('' . $rhs);
    
    return 1;
}

[download]

In reply to Re^2: check if 2 values are equal by eXile
in thread check if 2 values are equal by eXile

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.