File perl-List-Pairwise.spec of Package perl-List-Pairwise

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File perl-List-Pairwise.spec of Package perl-List-Pairwise (Revision 8286b3e4938a99bdc8e5239b9a3415f8)

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#
# spec file for package perl-List-Pairwise
#
# Copyright (c) 2014 SUSE LINUX Products GmbH, Nuernberg, Germany.
#
# All modifications and additions to the file contributed by third parties
# remain the property of their copyright owners, unless otherwise agreed
# upon. The license for this file, and modifications and additions to the
# file, is the same license as for the pristine package itself (unless the
# license for the pristine package is not an Open Source License, in which
# case the license is the MIT License). An "Open Source License" is a
# license that conforms to the Open Source Definition (Version 1.9)
# published by the Open Source Initiative.

# Please submit bugfixes or comments via http://bugs.opensuse.org/
#

Name:           perl-List-Pairwise
Version:        1.03
Release:        0
%define cpan_name List-Pairwise
Summary:        map/grep arrays and hashes pairwise
License:        Artistic-1.0 or GPL-1.0+
Group:          Development/Libraries/Perl
Url:            http://search.cpan.org/dist/List-Pairwise/
Source:         http://www.cpan.org/authors/id/T/TD/TDRUGEON/%{cpan_name}-%{version}.tar.gz
BuildArch:      noarch
BuildRoot:      %{_tmppath}/%{name}-%{version}-build
BuildRequires:  perl
BuildRequires:  perl-macros
#BuildRequires: perl(Devel::Cover)
#BuildRequires: perl(inc::Module::Install)
#BuildRequires: perl(JSON)
#BuildRequires: perl(List::Pairwise)
#BuildRequires: perl(LWP::Simple)
#BuildRequires: perl(Module::Build)
#BuildRequires: perl(Module::Install::Base)
#BuildRequires: perl(Parse::CPAN::Meta)
#BuildRequires: perl(YAML::Tiny)
%{perl_requires}

%description
'List::Pairwise' provides functions to map and grep lists two elements at a
time, setting $a and $b to each pair instead of setting $_ to each element.

As of version 1.01, List::Pairwise now tries to use the newly implemented
XS functions pairmap, pairgrep, pairfirst and pairs from List::Util 1.31
and up, resulting in a major speedup.

New code should now preferably use List::Util functions directly, with the
added benefit of relying on a Perl core module.

*/!\* as of version 1.03 List::Pairwise does not use List::Util, because
version up to the current one (1.39) presents a strange bug where a key can
get undefined after an assignement (see t/listutil.t with paimap instead of
mapp) */!\*

* mapp BLOCK LIST

* map_pairwise BLOCK LIST

Evaluates the BLOCK for each pair of LIST (locally setting $a and $b to
  each pair) and returns the list value composed of the results of each
  such evaluation. In scalar context, returns the total number of elements
  so generated (not pairs). Evaluates BLOCK in list context, so each
  element of LIST may produce zero, one, or more elements in the returned
  value.

Note that $a and $b are aliases to the list elements, so they can be used
  to modify the elements of the LIST, exept for hash keys ($a when LIST is
  a hash).

'mapp' is optimized in void context, and can thus be used to iterate
  lists pairwise.

'map_pairwise' is an alias for 'mapp'.

keys/values emulation (only slower):

my @keys = mapp {$a} %hash;
      my @keys = mapp {$a} @list;   # same
      my @values = mapp {$b} %hash;
      my @values = mapp {$b} @list; # same

copy (only slower):

my %b = mapp {$a, $b} %hash;

modify values in-place:

mapp {$b = lc($b)} %hash;
      mapp {$b = lc($b)} @list; # same

modifying hash keys in-place does not work with a hash:

mapp {$a = lc($a)} %hash;          # wrong
      my %b = mapp {lc($a) => $b} %hash; # ok
      %hash = mapp {lc($a) => $b} %hash; # also ok (copy)

modify array "keys" in-place does work:

mapp {$a = lc($a)} @list;

modify keys and copy:

%hash = mapp {lc($a) => $b} %hash;
      @hash = mapp {lc($a) => $b} @list; # same

reverse hash (does not work in-place):

my %reverse_a = mapp {$b, $a} %hash;

reverse array pairs in-place:

mapp { ($a, $b) = ($b, $a) } @list;

each emulation, iterating a list pairwise:

mapp {
          print "$a: $b\n";
      } %hash;
  
      mapp {
          print "$a: $b\n";
      } @list;

* grepp BLOCK LIST

* grep_pairwise BLOCK LIST

Evaluates the BLOCK in scalar context for each pair of LIST (locally
  setting $a and $b to each pair) and returns the list value consisting of
  those pairs for which the expression evaluated to true. In scalar
  context, returns the number of valid pairs, ie the number of times the
  expression was true.

So this equality stands:

(grepp BLOCK LIST) == 1/2 * scalar(my @list = (grepp BLOCK LIST))

Note that $a and $b are aliases to the list elements, so they can be used
  to modify the elements of the LIST, exept for hash keys ($a when LIST is
  a hash).

'grep_pairwise' is an alias for 'grepp'.

grep hash subset:

my %subset1 = grepp {$a =~ /^ba/} %hash;
      my %subset2 = grepp {$b < 5} %hash;

grep specific values:

my @values = mapp {$b} grepp {$a =~ /^ba/} %hash;

This does not work:

values grepp {$a =~ /^ba/} %hash;

values() and keys() expect a hash, whereas grepp returns a list

* firstp BLOCK LIST

* first_pairwise BLOCK LIST

Evaluates the BLOCK in scalar context for each pair of LIST (locally
  setting $a and $b to each pair) and returns the first pair for which the
  expression evaluated to true. In scalar context, returns 1 if a valid
  pair was found.

'firstp' can be used to iterate lists pairwise as does 'mapp', but with
  the additional option of using the value returned by the BLOCK as a
  'last' statement

my $i;
      firstp {
          print "$a: $b\n";
          ++$i==5 # last after 5 iterations
      } %hash;

* lastp BLOCK LIST

* last_pairwise BLOCK LIST

Evaluates the BLOCK in scalar context for each pair of LIST (locally
  setting $a and $b to each pair) and returns the last pair for which the
  expression evaluated to true. In scalar context, returns 1 if a valid
  pair was found.

* pair LIST

Returns a list of pairs as array references.

my @pairs = pair @list;
      my @pairs = mapp {[$a, $b]} @list; # same, but slower

'pair' can be used in combination with sort, map and grep to do ordered
  hash-like manipulations in long chains/streams:

my @ranges =
          sort { $a->[0] <=> $b->[0] or $a->[1] <=> $b->[1] }
          grep { $_->[0] < $_->[1] }
          pair
          /\b(\d+)-(\d+)\b/g
      ;

%prep
%setup -q -n %{cpan_name}-%{version}
find . -type f -print0 | xargs -0 chmod 644

%build
%{__perl} Makefile.PL INSTALLDIRS=vendor
%{__make} %{?_smp_mflags}

%check
%{__make} test

%install
%perl_make_install
%perl_process_packlist
%perl_gen_filelist

%files -f %{name}.files
%defattr(-,root,root,755)
%doc Changelog

%changelog

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File perl-List-Pairwise.spec of Package perl-List-Pairwise (Revision 8286b3e4938a99bdc8e5239b9a3415f8)

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