RFC 143 (v1) Case ignoring eq and cmp operators

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=head1 TITLE

Case ignoring eq and cmp operators

=head1 VERSION

  Maintainer: Markus Peter <[email protected]>
  Date: 24 Aug 2000
  Version: 1
  Mailing List: [email protected]
  Number: 143

=head1 ABSTRACT

Perl currently only has C<eq> and C<cmp> operators which work case-sensitively.
It would be a useful addition to add case-insensitive equivalents.

=head1 DESCRIPTION

=head2 Problems with current ways to do it

Perl currently knows basically two methods for checking of equality of
strings case-insensitively:

 uc($a) eq uc($b)
 $a =~ /^$b$/i

and for comparing them one:

 uc($a) cmp uc($b)

The probably worst about these statements is that they look ugly. Also,
they further complicate statements and they are counter-intuitive for
beginners - why should I change the case of variables if I only want
to compare them?

The regexp mechanism has a case-insensitivity option (there's probably
no proper way to simulate it there I admit). With this in mind most
beginners will conclude the same is true for eq and cmp - after all
Perl is strong in text processing so how could such a feature miss?
Beginner code usually ends up using the case-insensitive regexps then
instead of the easier to read uppercase/equals combination.

=head2 Proposal

We apply something similar to the regexp modifiers to C<eq> and C<cmp>
as well, after a slash. The above examples would then be

  $a eq/i $b
  $a cmp/i $b

This still leaves some room for future additions to eq and cmp if desired
(stupid example: like ignoring all white space in the comparison or
whatever comes up)

=head1 IMPLEMENTATION

Probably has to be added to perl internals...

I wonder what will happen with overloads though - is eq/i a new operator
to overload or is the case-insensitivity somehow magically done by the
Perl interpreter even though eq was overloaded? This probably could lead
to problems...

=head1 REFERENCES

perlop manpage for eq and cmp

String.equalsIgnoreCase() method in Java