From 320d8694fec25ed148613684543b5a0504a046ae Mon Sep 17 00:00:00 2001 From: Siep Kroonenberg Date: Thu, 17 Feb 2011 17:57:31 +0000 Subject: New tlperl part XIV git-svn-id: svn://tug.org/texlive/trunk@21436 c570f23f-e606-0410-a88d-b1316a301751 --- Master/tlpkg/tlperl/lib/List/Util.pm | 233 +++++++++++++++++++++++++++++++++++ 1 file changed, 233 insertions(+) create mode 100644 Master/tlpkg/tlperl/lib/List/Util.pm (limited to 'Master/tlpkg/tlperl/lib/List/Util.pm') diff --git a/Master/tlpkg/tlperl/lib/List/Util.pm b/Master/tlpkg/tlperl/lib/List/Util.pm new file mode 100644 index 00000000000..2b51a69d79b --- /dev/null +++ b/Master/tlpkg/tlperl/lib/List/Util.pm @@ -0,0 +1,233 @@ +# List::Util.pm +# +# Copyright (c) 1997-2009 Graham Barr . All rights reserved. +# This program is free software; you can redistribute it and/or +# modify it under the same terms as Perl itself. +# +# This module is normally only loaded if the XS module is not available + +package List::Util; + +use strict; +use vars qw(@ISA @EXPORT_OK $VERSION $XS_VERSION $TESTING_PERL_ONLY); +require Exporter; + +@ISA = qw(Exporter); +@EXPORT_OK = qw(first min max minstr maxstr reduce sum shuffle); +$VERSION = "1.22"; +$XS_VERSION = $VERSION; +$VERSION = eval $VERSION; + +eval { + # PERL_DL_NONLAZY must be false, or any errors in loading will just + # cause the perl code to be tested + local $ENV{PERL_DL_NONLAZY} = 0 if $ENV{PERL_DL_NONLAZY}; + eval { + require XSLoader; + XSLoader::load('List::Util', $XS_VERSION); + 1; + } or do { + require DynaLoader; + local @ISA = qw(DynaLoader); + bootstrap List::Util $XS_VERSION; + }; +} unless $TESTING_PERL_ONLY; + + +if (!defined &sum) { + require List::Util::PP; + List::Util::PP->import; +} + +1; + +__END__ + +=head1 NAME + +List::Util - A selection of general-utility list subroutines + +=head1 SYNOPSIS + + use List::Util qw(first max maxstr min minstr reduce shuffle sum); + +=head1 DESCRIPTION + +C contains a selection of subroutines that people have +expressed would be nice to have in the perl core, but the usage would +not really be high enough to warrant the use of a keyword, and the size +so small such that being individual extensions would be wasteful. + +By default C does not export any subroutines. The +subroutines defined are + +=over 4 + +=item first BLOCK LIST + +Similar to C in that it evaluates BLOCK setting C<$_> to each element +of LIST in turn. C returns the first element where the result from +BLOCK is a true value. If BLOCK never returns true or LIST was empty then +C is returned. + + $foo = first { defined($_) } @list # first defined value in @list + $foo = first { $_ > $value } @list # first value in @list which + # is greater than $value + +This function could be implemented using C like this + + $foo = reduce { defined($a) ? $a : wanted($b) ? $b : undef } undef, @list + +for example wanted() could be defined() which would return the first +defined value in @list + +=item max LIST + +Returns the entry in the list with the highest numerical value. If the +list is empty then C is returned. + + $foo = max 1..10 # 10 + $foo = max 3,9,12 # 12 + $foo = max @bar, @baz # whatever + +This function could be implemented using C like this + + $foo = reduce { $a > $b ? $a : $b } 1..10 + +=item maxstr LIST + +Similar to C, but treats all the entries in the list as strings +and returns the highest string as defined by the C operator. +If the list is empty then C is returned. + + $foo = maxstr 'A'..'Z' # 'Z' + $foo = maxstr "hello","world" # "world" + $foo = maxstr @bar, @baz # whatever + +This function could be implemented using C like this + + $foo = reduce { $a gt $b ? $a : $b } 'A'..'Z' + +=item min LIST + +Similar to C but returns the entry in the list with the lowest +numerical value. If the list is empty then C is returned. + + $foo = min 1..10 # 1 + $foo = min 3,9,12 # 3 + $foo = min @bar, @baz # whatever + +This function could be implemented using C like this + + $foo = reduce { $a < $b ? $a : $b } 1..10 + +=item minstr LIST + +Similar to C, but treats all the entries in the list as strings +and returns the lowest string as defined by the C operator. +If the list is empty then C is returned. + + $foo = minstr 'A'..'Z' # 'A' + $foo = minstr "hello","world" # "hello" + $foo = minstr @bar, @baz # whatever + +This function could be implemented using C like this + + $foo = reduce { $a lt $b ? $a : $b } 'A'..'Z' + +=item reduce BLOCK LIST + +Reduces LIST by calling BLOCK, in a scalar context, multiple times, +setting C<$a> and C<$b> each time. The first call will be with C<$a> +and C<$b> set to the first two elements of the list, subsequent +calls will be done by setting C<$a> to the result of the previous +call and C<$b> to the next element in the list. + +Returns the result of the last call to BLOCK. If LIST is empty then +C is returned. If LIST only contains one element then that +element is returned and BLOCK is not executed. + + $foo = reduce { $a < $b ? $a : $b } 1..10 # min + $foo = reduce { $a lt $b ? $a : $b } 'aa'..'zz' # minstr + $foo = reduce { $a + $b } 1 .. 10 # sum + $foo = reduce { $a . $b } @bar # concat + +If your algorithm requires that C produce an identity value, then +make sure that you always pass that identity value as the first argument to prevent +C being returned + + $foo = reduce { $a + $b } 0, @values; # sum with 0 identity value + +=item shuffle LIST + +Returns the elements of LIST in a random order + + @cards = shuffle 0..51 # 0..51 in a random order + +=item sum LIST + +Returns the sum of all the elements in LIST. If LIST is empty then +C is returned. + + $foo = sum 1..10 # 55 + $foo = sum 3,9,12 # 24 + $foo = sum @bar, @baz # whatever + +This function could be implemented using C like this + + $foo = reduce { $a + $b } 1..10 + +If your algorithm requires that C produce an identity of 0, then +make sure that you always pass C<0> as the first argument to prevent +C being returned + + $foo = sum 0, @values; + +=back + +=head1 KNOWN BUGS + +With perl versions prior to 5.005 there are some cases where reduce +will return an incorrect result. This will show up as test 7 of +reduce.t failing. + +=head1 SUGGESTED ADDITIONS + +The following are additions that have been requested, but I have been reluctant +to add due to them being very simple to implement in perl + + # One argument is true + + sub any { $_ && return 1 for @_; 0 } + + # All arguments are true + + sub all { $_ || return 0 for @_; 1 } + + # All arguments are false + + sub none { $_ && return 0 for @_; 1 } + + # One argument is false + + sub notall { $_ || return 1 for @_; 0 } + + # How many elements are true + + sub true { scalar grep { $_ } @_ } + + # How many elements are false + + sub false { scalar grep { !$_ } @_ } + +=head1 SEE ALSO + +L, L + +=head1 COPYRIGHT + +Copyright (c) 1997-2007 Graham Barr . All rights reserved. +This program is free software; you can redistribute it and/or +modify it under the same terms as Perl itself. + +=cut -- cgit v1.2.3