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authorNorbert Preining <preining@logic.at>2010-02-28 09:36:33 +0000
committerNorbert Preining <preining@logic.at>2010-02-28 09:36:33 +0000
commit5589232e99f0fa13868111280c5b64ce9dc25730 (patch)
tree28f2e6ff422108ac87934aff9c3fc5911963625c /Master/tlpkg/tlperl.straw/lib/Number/Compare.pm
parenta6f5de6eed80d66fbd23ceabda7edf22b8162236 (diff)
add a tlperl.straw directory for public inspection
git-svn-id: svn://tug.org/texlive/trunk@17235 c570f23f-e606-0410-a88d-b1316a301751
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+# $Id: Compare.pm 846 2002-10-25 15:46:01Z richardc $
+package Number::Compare;
+use strict;
+use Carp qw(croak);
+use vars qw/$VERSION/;
+$VERSION = '0.01';
+
+sub new {
+ my $referent = shift;
+ my $class = ref $referent || $referent;
+ my $expr = $class->parse_to_perl( shift );
+
+ bless eval "sub { \$_[0] $expr }", $class;
+}
+
+sub parse_to_perl {
+ shift;
+ my $test = shift;
+
+ $test =~ m{^
+ ([<>]=?)? # comparison
+ (.*?) # value
+ ([kmg]i?)? # magnitude
+ $}ix
+ or croak "don't understand '$test' as a test";
+
+ my $comparison = $1 || '==';
+ my $target = $2;
+ my $magnitude = $3;
+ $target *= 1000 if lc $magnitude eq 'k';
+ $target *= 1024 if lc $magnitude eq 'ki';
+ $target *= 1000000 if lc $magnitude eq 'm';
+ $target *= 1024*1024 if lc $magnitude eq 'mi';
+ $target *= 1000000000 if lc $magnitude eq 'g';
+ $target *= 1024*1024*1024 if lc $magnitude eq 'gi';
+
+ return "$comparison $target";
+}
+
+sub test { $_[0]->( $_[1] ) }
+
+1;
+
+__END__
+
+=head1 NAME
+
+Number::Compare - numeric comparisons
+
+=head1 SYNOPSIS
+
+ Number::Compare->new(">1Ki")->test(1025); # is 1025 > 1024
+
+ my $c = Number::Compare->new(">1M");
+ $c->(1_200_000); # slightly terser invocation
+
+=head1 DESCRIPTION
+
+Number::Compare compiles a simple comparison to an anonymous
+subroutine, which you can call with a value to be tested again.
+
+Now this would be very pointless, if Number::Compare didn't understand
+magnitudes.
+
+The target value may use magnitudes of kilobytes (C<k>, C<ki>),
+megabytes (C<m>, C<mi>), or gigabytes (C<g>, C<gi>). Those suffixed
+with an C<i> use the appropriate 2**n version in accordance with the
+IEC standard: http://physics.nist.gov/cuu/Units/binary.html
+
+=head1 METHODS
+
+=head2 ->new( $test )
+
+Returns a new object that compares the specified test.
+
+=head2 ->test( $value )
+
+A longhanded version of $compare->( $value ). Predates blessed
+subroutine reference implementation.
+
+=head2 ->parse_to_perl( $test )
+
+Returns a perl code fragment equivalent to the test.
+
+=head1 AUTHOR
+
+Richard Clamp <richardc@unixbeard.net>
+
+=head1 COPYRIGHT
+
+Copyright (C) 2002 Richard Clamp. All Rights Reserved.
+
+This module is free software; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+=head1 SEE ALSO
+
+http://physics.nist.gov/cuu/Units/binary.html
+
+=cut