Ubuntu Manpage: Data::Dmp - Dump Perl data structures as Perl code

Provided by: libdata-dmp-perl_0.14-1_all

NAME

       Data::Dmp - Dump Perl data structures as Perl code

VERSION

       This document describes version 0.14 of Data::Dmp (from Perl distribution Data-Dmp), released on
       2015-12-27.

SYNOPSIS

        use Data::Dmp; # exports dd() and dmp()
        dd [1, 2, 3]; # prints "[1,2,3]"
        $a = dmp({a => 1}); # -> "{a=>1}"

DESCRIPTION

       Data::Dmp is a Perl dumper like Data::Dumper. It's compact (only about 150 lines of code long), starts
       fast and does not use other module except Regexp::Stringify when dumping regexes. It produces compact
       output (similar to Data::Dumper::Concise). It roughly has the same speed as Data::Dumper (usually a bit
       faster for smaller structures), but does not offer the various formatting options. It supports dumping
       objects, regexes, circular structures, coderefs. Its code is based on Data::Dump.

FUNCTIONS

   dd($data, ...) => $data ...
       Exported by default. Like "Data::Dump"'s "dd" (a.k.a. "dump"), print one or more data to STDOUT. Unlike
       "Data::Dump"'s "dd", it always prints and return the original data (like XXX), making it convenient to
       insert into expressions. This also removes ambiguity and saves one "wantarray()" call.

   dmp($data, ...) => $str
       Exported by default. Return dump result as string. Unlike "Data::Dump"'s "dd" (a.k.a. "dump"), it never
       prints and only return the data.

SETTINGS

   $Data::Dmp::OPT_PERL_VERSION => str (default: 5.010)
       Set target Perl version. If you set this to, say 5.010, then the dumped code will keep compatibility with
       Perl 5.10.0. This is used in the following ways:

       •   passed to Regexp::Stringify

       •   when dumping code references

           For example, in perls earlier than 5.016, feature.pm does not understand:

            no feature ':all';

           so we replace it with:

            no feature;

   $Data::Dmp::OPT_REMOVE_PRAGMAS => bool (default: 0)
       If set to 1, then pragmas at the start of coderef dump will be removed. Coderef dump is produced by
       B::Deparse and is of the form like:

        sub { use feature 'current_sub', 'evalbytes', 'fc', 'say', 'state', 'switch', 'unicode_strings', 'unicode_eval'; $a <=> $b }

       If you want to dump short coderefs, the pragmas might be distracting. You can turn turn on this option
       which will make the above dump become:

        sub { $a <=> $b }

       Note that without the pragmas, the dump might be incorrect.

BENCHMARKS

        [1..10]:
                              Rate  Data::Dump Data::Dumper Data::Dmp
        Data::Dump     28356+-42/s          --       -66.8%    -77.5%
        Data::Dumper  85500+-290/s 201.5+-1.1%           --    -32.3%
        Data::Dmp    126260+-210/s  345.26+-1% 47.67+-0.56%        --

        [1..100]:
                               Rate   Data::Dump Data::Dumper Data::Dmp
        Data::Dump    3449.1+-5.1/s           --       -77.4%    -78.3%
        Data::Dumper    15252+-31/s  342.2+-1.1%           --     -4.1%
        Data::Dmp    15905.9+-5.8/s 361.16+-0.7%  4.29+-0.22%        --

        Some mixed structure:
                            Rate    Data::Dump    Data::Dmp Data::Dumper
        Data::Dump    7840+-13/s            --       -74.1%       -79.2%
        Data::Dmp    30302+-42/s 286.49+-0.83%           --       -19.5%
        Data::Dumper 37637+-72/s     380+-1.2% 24.21+-0.29%           --

FAQ

When to use Data::Dmp? How does it compare to other dumper modules?
Data::Dmp might be suitable for you if you want a relatively fast pure-Perl data structure dumper to
eval-able Perl code. It produces compact, single-line Perl code but offers little/no formatting options.
Data::Dmp and Data::Dump module family usually produce Perl code that is "more eval-able", e.g. it can
recreate circular structure.

Data::Dump produces nicer output (some alignment, use of range operator to shorten lists, use of base64
for binary data, etc) but no built-in option to produce compact/single-line output. It's also relatively
slow. I usually use its variant, Data::Dump::Color, for console debugging.

Data::Dumper is core module, offers a lot of formatting options (like disabling hash key sorting, setting
verboseness/indent level, and so on) but you usually have to configure it quite a bit before it does
exactly like you want (that's why there are modules on CPAN that are just wrapping Data::Dumper with some
configuration, like Data::Dumper::Concise et al). It does not support dumping Perl code that can recreate
circular structures.

Of course, dumping to eval-able Perl code is slow (not to mention the cost of re-loading the code back to
in-memory data, via eval-ing) compared to dumping to JSON, YAML, Sereal, or other format. So you need to
decide first whether this is the appropriate route you want to take. (But note that there is also
Data::Dumper::Limited and Data::Undump which uses a format similar to Data::Dumper but lets you load the
serialized data without eval-ing them, thus achieving the speed comparable to JSON::XS).

HOMEPAGE

       Please visit the project's homepage at <https://metacpan.org/release/Data-Dmp>.

SOURCE

       Source repository is at <https://github.com/perlancar/perl-Data-Dmp>.

BUGS

       Please report any bugs or feature requests on the bugtracker website
       <https://rt.cpan.org/Public/Dist/Display.html?Name=Data-Dmp>

       When submitting a bug or request, please include a test-file or a patch to an existing test-file that
       illustrates the bug or desired feature.

AUTHOR

       perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2015 by perlancar@cpan.org.

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.