[![Build Status](https://travis-ci.org/lizmat/P5reverse.svg?branch=master)](https://travis-ci.org/lizmat/P5reverse) NAME ==== P5reverse - Implement Perl 5's reverse() built-in SYNOPSIS ======== use P5reverse; say reverse "Foo"; # ooF with "Zippo" { say reverse(); # oppiZ, may need parens to avoid compilation error } say reverse 1,2,3; # (3 2 1) with 1,2,3 { say reverse(); # (3 2 1), may need parens to avoid compilation error } DESCRIPTION =========== This module tries to mimic the behaviour of the `reverse` function of Perl 5 as closely as possible. ORIGINAL PERL 5 DOCUMENTATION ============================= reverse LIST In list context, returns a list value consisting of the elements of LIST in the opposite order. In scalar context, concatenates the elements of LIST and returns a string value with all characters in the opposite order. print join(", ", reverse "world", "Hello"); # Hello, world print scalar reverse "dlrow ,", "olleH"; # Hello, world Used without arguments in scalar context, reverse() reverses $_. $_ = "dlrow ,olleH"; print reverse; # No output, list context print scalar reverse; # Hello, world Note that reversing an array to itself (as in "@a = reverse @a") will preserve non-existent elements whenever possible; i.e., for non-magical arrays or for tied arrays with "EXISTS" and "DELETE" methods. This operator is also handy for inverting a hash, although there are some caveats. If a value is duplicated in the original hash, only one of those can be represented as a key in the inverted hash. Also, this has to unwind one hash and build a whole new one, which may take some time on a large hash, such as from a DBM file. %by_name = reverse %by_address; # Invert the hash PORTING CAVEATS =============== Whereas in Perl 5 the type of context determines how `reverse` operates, in this implementation it's the type of parameter that determines the semantics. When given a `List`, it will revert the order of the elements. When given something that can coerce to a `Str`, it will return a string with the characters reversed in order. AUTHOR ====== Elizabeth Mattijsen Source can be located at: https://github.com/lizmat/P5reverse . Comments and Pull Requests are wereverseome. COPYRIGHT AND LICENSE ===================== Copyright 2018 Elizabeth Mattijsen Re-imagined from Perl 5 as part of the CPAN Butterfly Plan. This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.