perlquestion
eXile
esteemed monks,
I'm overheating my brain on a function that checks if 2 values are equal, so i don't have to update a certain column in a SQL database. There are some things I think I need to take care of (like 0 vs "" vs undef, which are different in SQL).
I don't have the SQL-column definition available at compare time.
My 'equals' function currently looks like this:
<code>
sub equals {
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 == context ...
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;
}
</code>
This looks very bloated (and a candidate for thedailywtf ), and it feels like there must be bugs lurking in this.
<p>
I'm pretty sure this can be done a lot easier/better. Anybody got a better/smarter way to accomplish this type of comparing of 2 variables?
<p>
I'm sure somebody can come up with a nicer solution, that'll make me bang my head at my desk for at least an hour.