List::Gen::Perl6 - perl6 meta operators in perl5
many of the features found in List::Gen borrow ideas from perl6. however, since the syntax of perl5 and perl6 differ, some of the constructs in perl5 are longer/messier than in perl6. List::Gen::Perl6 is a source filter that makes some of List::Gen's features more syntactic.
List::Gen::Perl6
List::Gen
the new syntactic constructs are:
zip: generator Z generator zipwith: generator Z+ generator cross: generator X generator crosswith: generator X+ generator hyper: generator <<+>> generator hyper: generator >>+<< generator hyper: generator >>+>> generator hyper: generator <<+<< generator reduce: [+] list triangular reduction: [\+] list or [..+] list
in the above, + can be any perl binary operator.
+
here is a table showing the correspondence between the source filter constructs, the native overloaded ops, and the operation expanded into methods and functions.
List::Gen::Perl6 List::Gen List::Gen expanded <1..3> Z <4..6> ~~ <1..3> | <4..6> ~~ <1..3>->zip(<4..6>) <1..3> Z. <4..6> ~~ <1..3> |'.'| <4..6> ~~ <1..3>->zip('.' => <4..6>) <1..3> X <4..6> ~~ <1..3> x <4..6> ~~ <1..3>->cross(<4..6>) <1..3> X. <4..6> ~~ <1..3> x'.'x <4..6> ~~ <1..3>->cross('.' => <4..6>) <1..3> <<+>> <4..6> ~~ <1..3> <<'+'>> <4..6> ~~ <1..3>->hyper('<<+>>', <4..6>) [+] 1..10 ~~ <[+] 1..10> ~~ reduce {$_[0] + $_[1]} 1 .. 10 [+]->(1..10) ~~ <[+]>->(1..10) ~~ same as above [\+] 1..10 ~~ <[..+] 1..10> ~~ scan {$_[0] + $_[1]} 1 .. 10 [\+]->(1..10) ~~ <[..+]>->(1..10) ~~ same as above
except for normal reductions [+] , all of the new constructs return a generator.
[+]
you can flip the arguments to an operator with R or r and in some cases ~
R
r
~
ZR. Zr. Z~. XR. Xr. X~. <<R.>> <<r.>> <<~.>> [R.] [r.] n/a [\R.] [\r.] n/a
when used without a following argument, reductions and triangular reductions will return a code reference that will perform the reduction on its arguments.
my $sum = [+]; say $sum->(1..10); # 55
reductions can take a list of scalars, or a single generator as their argument.
only the left hand side of the zip, cross, and hyper operators needs to be a generator. zip and cross will upgrade their rhs to a generator if it is an array. hyper will upgrade it's rhs to a generator if it is an array or a scalar.
the source filter is limited in scope, and should not harm other parts of the code, however, source filters are notoriously difficult to fully test, so take that with a grain of salt. due to limitations of Filter::Simple, hyper operators will be filtered in both code and strings. all other filters should skip strings.
this code is not really intended for serious work, ymmv.
Eric Strom, <asg at cpan.org>
<asg at cpan.org>
report any bugs / feature requests to bug-list-gen at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=List-Gen.
bug-list-gen at rt.cpan.org
comments / feedback / patches are also welcome.
copyright 2009-2011 Eric Strom.
this program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.
see http://dev.perl.org/licenses/ for more information.
To install List::Gen, copy and paste the appropriate command in to your terminal.
cpanm
cpanm List::Gen
CPAN shell
perl -MCPAN -e shell install List::Gen
For more information on module installation, please visit the detailed CPAN module installation guide.