The Regexp::Common::debian is collection of REs for various strings
  found in the Debian Porject <http://debian.org>.  It's no way intended
  to be a validation tool.

  R::C::d needs perl "v5.10.0" or later because:

  *   4 patterns (29%) make use of decent perls (one doesn't make it
      through with anything older);

  *   It's time to move, "v5.10.0" is six year old and three years

  *   "lenny" is four year old and a year no-support;


  The R::C::d builds with Module::Build.

      $ perl Build.PL
      $ perl Build
      $ perl Build test
      $ perl Build install

  Since we're about strings we need a lots of strings to test against
  (Test::More, unspecified version).  To access them easily (it's all
  about reuse, not implemented yet) I need an apropriate storage. 
  Accidentally it's YAML::Tiny (unspecified version).

  "v0.2.1" Reading reports of cpantesters I've got to conclusion that
  YAML::Tiny isn't popular.  ("v0.2.13" Wandering through errors of
  "v0.2.12" I should say it totally is.) And avoiding installing (or
  unability to install (there could be reasons)) build requirements
  isn't that uncommon.  Although I experience a strong belief that some
  YAML reader happens to be installed anyway.  And still I can't find a
  way to specify that *%build_requires* one of but all known to me YAML
  reader.  So here is a dirty trick.  t::TestSuite attempts to require()
  one of known (to me, see below) YAML reader.  Then (upon initial "perl
  Build.PL") t::TestSuite is asked what it has found (if nothing then
  cosmetic "Compilation failed in require" message will be seen).  And
  one what has been found will be added to *%build_requires*; If nothing
  then fair YAML::Tiny will be added.  (I think it's fair because
  YAML::Tiny is pure-Perl, small footprint, and no dependencies.)

  (note) I'm talking about "known to me YAML readers" because I've found
  out that different YAML readers treat source differently.  So I
  attempt to keep t/*.yaml files semantically equal and sintactically
  correct.  Hopefully there're no differences among versions in wild.

  "v0.2.13" (Actually, this feature has been here for years.) Any
  supported YAML reader can be enforced with $ENV{RCD_YAML_ENGINE} magic
  (in spite of any build-time choice):

      RCD_YAML_ENGINE=syck ./Build test

  Readers are assigned by nicks.  Here they are:

  *   "syck" -- YAML::Syck.

  *   "xs" -- YAML::XS.

  *   "tiny" -- YAML::Tiny.

  *   "old" -- YAML.

  *   "data" -- Data::YAML::Reader 'does not support multi-line quoted
      scalars', 'YAML document header not found' -- unsupported, so far.

  "v0.2.2" Various (all, except t/preferences.t and t/sourceslist.t)
  test-units know a magic command '$ENV{RCD_ASK_DEBIAN}'.  Apply it this
  way (enabling all possible external inquiries):

      RCD_ASK_DEBIAN=all ./Build test

  or this (separate keys with any non-word):

      RCD_ASK_DEBIAN=binary,architecture ./Build test

  When applied a test-unit would ask Debian's commands or inspect Debian
  specific files for information the test-unit is interested in.  For
  obvious reasons that magic will fail on non-Debian system; So don't. 
  Although if used correctly that could warn of strange ('not known
  before') compatibility problems.  Details:

  architecture of t/architecture.t
      This asks "dpkg-architecture -L" for list of known architectures
      (per Section 11.1 of debian-policy).  That wouldn't find
      architectures dropped (had that happen ever?) but omissions won't
      stay unnoted anymore.

  binary of t/archive.misc.t
      "v0.2.3" Inspects all records in /var/lib/apt/lists/*_Packages,
      extracts *Filename:* entries and matches all of them against
      "m/^$RE{debian}{archive}{binary}$/".  All (if any) failure will be
      reported at the end.

  changelog of t/changelog.t
      "v0.2.8" That will inspect /usr/share/doc/*/changelog.Debian
      files.  To do a complete scan it would take loads of time
      (really).  You should understand, that's not enough to just run
      through changelogs.  It has to be verified that none entry is
      skipped.  The only reliable (for sake of interface, and,
      trivially, presence) source of verification is
      "dpkg-parsechangelog".  And here's the fork-mare.  "perl" forks
      "shell", then "perl", then "perl" again.  There seems to be fork
      of "tail" too.  And that for each entry.  (Not to count "gunzip"
      to decompress the changelog.) "loadavg" climbs over 1.50..2.00
      You've got the picture.  Although that's where choice begins.

      "v0.2.12" That happens that "urgency=high", probably when it's
      that really high, is expressed in blocks (like this:
      "urgency=HIGH").  $RE{d}{changelog} is case-keeping, and then
      dpkg-parsechangelog(1) strikes back and lowercase.  From now on
      such manipulations won't fail a particular entry.

          "v0.2.9" That defaults to "changelog=5".  See below.

          Only one changelog will be checked.  The one that "eq"s.  The
          package name is picked from directory name.

          Only those changelogs will be checked that "m/^a/".

          "v0.2.9" That will check all changelogs, although it will look
          no more than requested number of entries deep.

               v0.2.9 ~15min ~1.2K changelogs
              v0.2.12 ~30min ~1.3K changelogs ~6.0K subchecks;
              v0.2.13 ~35min ~1.3K changelogs ~6.1K subchecks;

          And that has a perfect sense.  Do you know that "cron" once
          changed it's name to "Cron" (beware leading block)
          (cron_3.0pl1-46)? C'mon, it has happened 12 (tweleve) years
          ago! (And you know what? That default is pretty fair
          (liblog-log4perl-perl_1.16-1).  Probably it should look for
          time passed but entry number.)

          "v0.2.9" That's different.  It will check as many entries as
          possible (there are changelogs what $RE{d}{changelog} finds
          out more entries than dpkg-parsechangelog ("dpkg_1.2.13" vs
          "dpkg_0.93.79"), but if the offending record is more than that
          far from top then it's reported and otherwise ignored.

               v0.2.9  ~3h ~1.2K changelogs ~45K subchecks
              v0.2.12 ~5¼h ~1.3K changelogs ~63K subchecks
              v0.2.13 ~5½h ~1.3K changelogs ~59K subckecks

          "v0.2.12" That's a mix of *changelog=5* and *changelog=-5*
          (thanks to irda-utils_0.9.18-8.1 and mime-support_3.49-1).  It
          goes no more than configured entries deep and ignores (and
          reports) any errors.

          (bug) "v0.2.9" That will check all changelogs, check all
          possible entries and BAIL_OUT off first failure.  Shortly --
          don't.  You're warned.  (Although, do it.  t/changelog.t will
          give up pretty soon.)

      To slightly sweeten all that, t/changelog.t attempts to filter
      duplicates.  And it BAIL_OUTs upon first failure.

  package of t/package.t
      "v0.2.10" Nothing special.  Output of "dpkg-query -f
      '${Package}\n' -W" is matched against m/^$RE{debian}{package}$/. 
      Probably should parse *_Packagees.

  source of t/archive.source.t
      "v0.2.3" Inspects all records in /var/lib/apt/lists/*_Sources,
      extracts *Files:* entries, then collects trailing filenames.  They
      are matched against "m/^$RE{debian}{archive}{source_1_0}$/",
      "m/^$RE{debian}{archive}{patch_3_0_quilt}$/", and
      "m/^$RE{debian}{archive}{dsc}$/" (in fact "||").  If none matches
      then it will be reported at the end. 
      "m/$RE{debian}{archive}{changes}/" is missing here because there
      is no source of such on no-build system.

  version of t/version.t
      "v0.2.10" Again nothing special.  Output of "dpkg-query -f
      '${Version}\n' -W" is matched against m/^$RE{debian}{version}$/. 
      Probably should parse *_Packages too.

  If any test string fails I need to know what and how.  To provide that
  info I've picked Test::Differences (maybe there's other option I'm not
  aware of?) (I'm, Test::Deep).  "v0.60" of T::D closes
  [38320@rt.cpan.org] and [41241@rt.cpan.org].


  Distribution -- <http://search.cpan.org/dist/Regexp-Common-debian/>


  Please report here --


  *   Copyright 2008--2010, 2014 Eric Pozharski <whynot@cpan.org>


  *   GNU Lesser General Public License v3