envassert.self-contained

#!/usr/bin/env perl

# This chunk of stuff was generated by App::FatPacker. To find the original
# file's code, look for the end of this BEGIN block or the string 'FATPACK'
BEGIN {
my %fatpacked;

$fatpacked{"Env/Assert.pm"} = '#line '.(1+__LINE__).' "'.__FILE__."\"\n".<<'ENV_ASSERT';
  ## no critic [ControlStructures::ProhibitPostfixControls]
  ## no critic [ValuesAndExpressions::ProhibitConstantPragma]
  ## no critic (ControlStructures::ProhibitCascadingIfElse)
  package Env::Assert;
  use strict;
  use warnings;
  
  use Exporter 'import';
  our @EXPORT_OK = qw(
      assert
      report_errors
      file_to_desc
      );
  our %EXPORT_TAGS = (
      'all'          => [qw( assert report_errors file_to_desc )],
  );
  
  use English qw( -no_match_vars ); # Avoids regex performance penalty in perl 5.18 and earlier
  use Carp;
  
  # ABSTRACT: Ensure that the environment variables match what you need, or abort.
  
  # VERSION: generated by DZP::OurPkgVersion
  
  use constant  {
      ENV_ASSERT_MISSING_FROM_ENVIRONMENT => 1,
      ENV_ASSERT_INVALID_CONTENT_IN_VARIABLE => 2,
      ENV_ASSERT_MISSING_FROM_DEFINITION => 3,
      DEFAULT_PARAMETER_BREAK_AT_FIRST_ERROR => 0,
      INDENT => q{    },
  };
  
  =pod
  
  =for stopwords params env
  
  =head1 STATUS
  
  Package Env::Assert is currently being developed so changes in the API are possible,
  though not likely.
  
  
  =head1 SYNOPSIS
  
      use Env::Assert qw( assert report_errors );
  
      my %want = (
          options => {
              exact => 1,
          },
          variables => {
              USER => { regexp => '^[[:word:]]{1}$', required => 1 },
          },
      );
      my %parameters;
      $parameters{'break_at_first_error'} = 1;
      my $r = assert( \%ENV, \%want, \%parameters );
      if( ! $r->{'success'} ) {
          print report_errors( $r->{'errors'} );
      }
  
  
  =head1 NOTES
  
  =cut
  
  
  =head1 DEPENDENCIES
  
  No external dependencies outside Perl's standard distribution.
  
  
  =head1 FUNCTIONS
  
  No functions are automatically exported to the calling namespace.
  
  =head2 assert( \%env, \%want, \%params )
  
  Ensure your environment, parameter I<env> (hashref), matches with
  the environment description, parameter I<want> (hashref).
  Use parameter I<params> (hashref) to specify processing options.
  
  Supported params:
  
  =over 8
  
  =item break_at_first_error
  
  Verify environment only up until the first error.
  Then break and return with only that error.
  
  =back
  
  Return: hashref: { success => 1/0, errors => hashref, };
  
  
  =cut
  
  sub assert {
      my ($env, $want, $params) = @_;
      $params = {} if ! $params;
      croak 'Invalid options. Not a hash' if( ref $env ne 'HASH' || ref $want ne 'HASH' );
  
      # Set default options
      $params->{'break_at_first_error'} //= DEFAULT_PARAMETER_BREAK_AT_FIRST_ERROR;
  
      my $success = 1;
      my %errors;
      my $vars = $want->{'variables'};
      my $opts = $want->{'options'};
      foreach my $var_name (keys %{ $vars }) {
          my $var = $vars->{$var_name};
          my $required = $var->{'required'}//1;
          my $regexp = $var->{'regexp'}//q{.*};
          if( ( $opts->{'exact'} || $required ) && ! defined $env->{$var_name} ) {
              $success = 0;
              $errors{'variables'}->{ $var_name } = {
                  type => ENV_ASSERT_MISSING_FROM_ENVIRONMENT,
                  message => "Variable $var_name is missing from environment",
              };
              goto EXIT if( $params->{'break_at_first_error'} );
          }
          elsif( $env->{$var_name} !~ m/$regexp/msx ) {
              $success = 0;
              $errors{'variables'}->{ $var_name } = {
                  type => ENV_ASSERT_INVALID_CONTENT_IN_VARIABLE,
                  message => "Variable $var_name has invalid content",
              };
              goto EXIT if( $params->{'break_at_first_error'} );
          }
      }
      if( $opts->{'exact'} ) {
          foreach my $var_name (keys %{ $env }) {
              if( ! exists $vars->{ $var_name } ) {
                  $success = 0;
                  $errors{'variables'}->{ $var_name } = {
                      type => ENV_ASSERT_MISSING_FROM_DEFINITION,
                      message => "Variable $var_name is missing from description",
                  };
                  goto EXIT if( $params->{'break_at_first_error'} );
              }
          }
      }
  
      EXIT:
      return { success => $success, errors => \%errors, };
  }
  
  =head2 report_errors( \%errors )
  
  Report errors in a nicely formatted way.
  
  =cut
  
  sub report_errors {
      my ($errors) = @_;
      my $out = q{};
      $out .= sprintf "Environment Assert: ERRORS:\n";
      foreach my $error_area_name (sort keys %{ $errors }) {
          $out .= sprintf "%s%s:\n", INDENT, $error_area_name;
          foreach my $error_key (sort keys %{ $errors->{$error_area_name} }) {
              $out .= sprintf "%s%s: %s\n", INDENT . INDENT, $error_key,
                  $errors->{$error_area_name}->{$error_key}->{'message'};
          }
      }
      return $out;
  }
  
  =head2 file_to_desc( @rows )
  
  Extract an environment description from a F<.envdesc> file.
  
  =cut
  
  sub file_to_desc {
      my @rows = @_;
      my %desc = ( 'options' => {}, 'variables' => {}, );
      foreach (@rows) {
          # This is envassert meta command
          ## no critic (RegularExpressions::ProhibitComplexRegexes)
          if(
              m{
              ^ [[:space:]]{0,} [#]{2}
              [[:space:]]{1,} envassert [[:space:]]{1,}
              [(] opts: [[:space:]]{0,} (?<opts> .*) [)]
              [[:space:]]{0,} $
              }msx
          ) {
              my $opts = _interpret_opts( $LAST_PAREN_MATCH{opts} );
              foreach ( keys %{ $opts } ) {
                  $desc{'options'}->{$_} = $opts->{$_};
              }
          } elsif(
              # This is comment row
              m{
                  ^ [[:space:]]{0,} [#]{1} .* $
              }msx
          ) {
              1;
          } elsif(
              # This is empty row
              m{
                  ^ [[:space:]]{0,} $
              }msx
          ) {
              1;
          } elsif(
              # This is env var description
              m{
                  ^ (?<name> [^=]{1,}) = (?<value> .*) $
              }msx
          ) {
              $desc{'variables'}->{ $LAST_PAREN_MATCH{name} } = {
                  regexp => $LAST_PAREN_MATCH{value}
              };
          }
      }
      return \%desc;
  }
  
  # Private subroutines
  
  sub _interpret_opts {
      my ($opts_str) = @_;
      my @opts = split qr{
          [[:space:]]{0,} [,] [[:space:]]{0,}
          }msx,
      $opts_str;
      my %opts;
      foreach (@opts) {
          my ($key, $val) = split qr/=/msx;
          $opts{$key} = $val;
      }
      return \%opts;
  }
  
  1;
ENV_ASSERT

$fatpacked{"Exporter.pm"} = '#line '.(1+__LINE__).' "'.__FILE__."\"\n".<<'EXPORTER';
  package Exporter;
  
  use strict;
  no strict 'refs';
  
  our $Debug = 0;
  our $ExportLevel = 0;
  our $Verbose ||= 0;
  our $VERSION = '5.77';
  our %Cache;
  
  sub as_heavy {
    require Exporter::Heavy;
    # Unfortunately, this does not work if the caller is aliased as *name = \&foo
    # Thus the need to create a lot of identical subroutines
    my $c = (caller(1))[3];
    $c =~ s/.*:://;
    \&{"Exporter::Heavy::heavy_$c"};
  }
  
  sub export {
    goto &{as_heavy()};
  }
  
  sub import {
    my $pkg = shift;
    my $callpkg = caller($ExportLevel);
  
    if ($pkg eq "Exporter" and @_ and $_[0] eq "import") {
      *{$callpkg."::import"} = \&import;
      return;
    }
  
    # We *need* to treat @{"$pkg\::EXPORT_FAIL"} since Carp uses it :-(
    my $exports = \@{"$pkg\::EXPORT"};
    # But, avoid creating things if they don't exist, which saves a couple of
    # hundred bytes per package processed.
    my $fail = ${$pkg . '::'}{EXPORT_FAIL} && \@{"$pkg\::EXPORT_FAIL"};
    return export $pkg, $callpkg, @_
      if $Verbose or $Debug or $fail && @$fail > 1;
    my $export_cache = ($Cache{$pkg} ||= {});
    my $args = @_ or @_ = @$exports;
  
    if ($args and not %$export_cache) {
      s/^&//, $export_cache->{$_} = 1
        foreach (@$exports, @{"$pkg\::EXPORT_OK"});
    }
    my $heavy;
    # Try very hard not to use {} and hence have to  enter scope on the foreach
    # We bomb out of the loop with last as soon as heavy is set.
    if ($args or $fail) {
      ($heavy = (/\W/ or $args and not exists $export_cache->{$_}
                 or $fail and @$fail and $_ eq $fail->[0])) and last
                   foreach (@_);
    } else {
      ($heavy = /\W/) and last
        foreach (@_);
    }
    return export $pkg, $callpkg, ($args ? @_ : ()) if $heavy;
    local $SIG{__WARN__} = 
  	sub {require Carp; &Carp::carp} if not $SIG{__WARN__};
    # shortcut for the common case of no type character
    *{"$callpkg\::$_"} = \&{"$pkg\::$_"} foreach @_;
  }
  
  # Default methods
  
  sub export_fail {
      my $self = shift;
      @_;
  }
  
  # Unfortunately, caller(1)[3] "does not work" if the caller is aliased as
  # *name = \&foo.  Thus the need to create a lot of identical subroutines
  # Otherwise we could have aliased them to export().
  
  sub export_to_level {
    goto &{as_heavy()};
  }
  
  sub export_tags {
    goto &{as_heavy()};
  }
  
  sub export_ok_tags {
    goto &{as_heavy()};
  }
  
  sub require_version {
    goto &{as_heavy()};
  }
  
  1;
  __END__
  
  =head1 NAME
  
  Exporter - Implements default import method for modules
  
  =head1 SYNOPSIS
  
  In module F<YourModule.pm>:
  
    package YourModule;
    use Exporter 'import';
    our @EXPORT_OK = qw(munge frobnicate);  # symbols to export on request
  
  or
  
    package YourModule;
    require Exporter;
    our @ISA = qw(Exporter);  # inherit all of Exporter's methods
    our @EXPORT_OK = qw(munge frobnicate);  # symbols to export on request
  
  or
  
    package YourModule;
    use parent 'Exporter';  # inherit all of Exporter's methods
    our @EXPORT_OK = qw(munge frobnicate);  # symbols to export on request
  
  In other files which wish to use C<YourModule>:
  
    use YourModule qw(frobnicate);      # import listed symbols
    frobnicate ($left, $right)          # calls YourModule::frobnicate
  
  Take a look at L</Good Practices> for some variants
  you will like to use in modern Perl code.
  
  =head1 DESCRIPTION
  
  The Exporter module implements an C<import> method which allows a module
  to export functions and variables to its users' namespaces.  Many modules
  use Exporter rather than implementing their own C<import> method because
  Exporter provides a highly flexible interface, with an implementation optimised
  for the common case.
  
  Perl automatically calls the C<import> method when processing a
  C<use> statement for a module.  Modules and C<use> are documented
  in L<perlfunc> and L<perlmod>.  Understanding the concept of
  modules and how the C<use> statement operates is important to
  understanding the Exporter.
  
  =head2 How to Export
  
  The arrays C<@EXPORT> and C<@EXPORT_OK> in a module hold lists of
  symbols that are going to be exported into the users name space by
  default, or which they can request to be exported, respectively.  The
  symbols can represent functions, scalars, arrays, hashes, or typeglobs.
  The symbols must be given by full name with the exception that the
  ampersand in front of a function is optional, e.g.
  
    our @EXPORT    = qw(afunc $scalar @array);   # afunc is a function
    our @EXPORT_OK = qw(&bfunc %hash *typeglob); # explicit prefix on &bfunc
  
  If you are only exporting function names it is recommended to omit the
  ampersand, as the implementation is faster this way.
  
  =head2 Selecting What to Export
  
  Do B<not> export method names!
  
  Do B<not> export anything else by default without a good reason!
  
  Exports pollute the namespace of the module user.  If you must export
  try to use C<@EXPORT_OK> in preference to C<@EXPORT> and avoid short or
  common symbol names to reduce the risk of name clashes.
  
  Generally anything not exported is still accessible from outside the
  module using the C<YourModule::item_name> (or C<< $blessed_ref->method >>)
  syntax.  By convention you can use a leading underscore on names to
  informally indicate that they are 'internal' and not for public use.
  
  (It is actually possible to get private functions by saying:
  
    my $subref = sub { ... };
    $subref->(@args);            # Call it as a function
    $obj->$subref(@args);        # Use it as a method
  
  However if you use them for methods it is up to you to figure out
  how to make inheritance work.)
  
  As a general rule, if the module is trying to be object oriented
  then export nothing.  If it's just a collection of functions then
  C<@EXPORT_OK> anything but use C<@EXPORT> with caution.  For function and
  method names use barewords in preference to names prefixed with
  ampersands for the export lists.
  
  Other module design guidelines can be found in L<perlmod>.
  
  =head2 How to Import
  
  In other files which wish to use your module there are three basic ways for
  them to load your module and import its symbols:
  
  =over 4
  
  =item C<use YourModule;>
  
  This imports all the symbols from YourModule's C<@EXPORT> into the namespace
  of the C<use> statement.
  
  =item C<use YourModule ();>
  
  This causes perl to load your module but does not import any symbols.
  
  =item C<use YourModule qw(...);>
  
  This imports only the symbols listed by the caller into their namespace.
  All listed symbols must be in your C<@EXPORT> or C<@EXPORT_OK>, else an error
  occurs.  The advanced export features of Exporter are accessed like this,
  but with list entries that are syntactically distinct from symbol names.
  
  =back
  
  Unless you want to use its advanced features, this is probably all you
  need to know to use Exporter.
  
  =head1 Advanced Features
  
  =head2 Specialised Import Lists
  
  If any of the entries in an import list begins with !, : or / then
  the list is treated as a series of specifications which either add to
  or delete from the list of names to import.  They are processed left to
  right. Specifications are in the form:
  
      [!]name         This name only
      [!]:DEFAULT     All names in @EXPORT
      [!]:tag         All names in $EXPORT_TAGS{tag} anonymous array
      [!]/pattern/    All names in @EXPORT and @EXPORT_OK which match
  
  A leading ! indicates that matching names should be deleted from the
  list of names to import.  If the first specification is a deletion it
  is treated as though preceded by :DEFAULT.  If you just want to import
  extra names in addition to the default set you will still need to
  include :DEFAULT explicitly.
  
  e.g., F<Module.pm> defines:
  
      our @EXPORT      = qw(A1 A2 A3 A4 A5);
      our @EXPORT_OK   = qw(B1 B2 B3 B4 B5);
      our %EXPORT_TAGS = (T1 => [qw(A1 A2 B1 B2)], T2 => [qw(A1 A2 B3 B4)]);
  
  Note that you cannot use tags in @EXPORT or @EXPORT_OK.
  
  Names in EXPORT_TAGS must also appear in @EXPORT or @EXPORT_OK.
  
  An application using Module can say something like:
  
      use Module qw(:DEFAULT :T2 !B3 A3);
  
  Other examples include:
  
      use Socket qw(!/^[AP]F_/ !SOMAXCONN !SOL_SOCKET);
      use POSIX  qw(:errno_h :termios_h !TCSADRAIN !/^EXIT/);
  
  Remember that most patterns (using //) will need to be anchored
  with a leading ^, e.g., C</^EXIT/> rather than C</EXIT/>.
  
  You can say C<BEGIN { $Exporter::Verbose=1 }> to see how the
  specifications are being processed and what is actually being imported
  into modules.
  
  =head2 Exporting Without Using Exporter's import Method
  
  Exporter has a special method, 'export_to_level' which is used in situations
  where you can't directly call Exporter's
  import method.  The export_to_level
  method looks like:
  
      MyPackage->export_to_level(
  	$where_to_export, $package, @what_to_export
      );
  
  where C<$where_to_export> is an integer telling how far up the calling stack
  to export your symbols, and C<@what_to_export> is an array telling what
  symbols *to* export (usually this is C<@_>).  The C<$package> argument is
  currently unused.
  
  For example, suppose that you have a module, A, which already has an
  import function:
  
      package A;
  
      our @ISA = qw(Exporter);
      our @EXPORT_OK = qw($b);
  
      sub import
      {
  	$A::b = 1;     # not a very useful import method
      }
  
  and you want to Export symbol C<$A::b> back to the module that called 
  package A.  Since Exporter relies on the import method to work, via 
  inheritance, as it stands Exporter::import() will never get called. 
  Instead, say the following:
  
      package A;
      our @ISA = qw(Exporter);
      our @EXPORT_OK = qw($b);
  
      sub import
      {
  	$A::b = 1;
  	A->export_to_level(1, @_);
      }
  
  This will export the symbols one level 'above' the current package - ie: to 
  the program or module that used package A. 
  
  Note: Be careful not to modify C<@_> at all before you call export_to_level
  - or people using your package will get very unexplained results!
  
  =head2 Exporting Without Inheriting from Exporter
  
  By including Exporter in your C<@ISA> you inherit an Exporter's import() method
  but you also inherit several other helper methods which you probably don't
  want and complicate the inheritance tree.  To avoid this you can do:
  
    package YourModule;
    use Exporter qw(import);
  
  which will export Exporter's own import() method into YourModule.
  Everything will work as before but you won't need to include Exporter in
  C<@YourModule::ISA>.
  
  Note: This feature was introduced in version 5.57
  of Exporter, released with perl 5.8.3.
  
  =head2 Module Version Checking
  
  The Exporter module will convert an attempt to import a number from a
  module into a call to C<< $module_name->VERSION($value) >>.  This can
  be used to validate that the version of the module being used is
  greater than or equal to the required version.
  
  For historical reasons, Exporter supplies a C<require_version> method that
  simply delegates to C<VERSION>.  Originally, before C<UNIVERSAL::VERSION>
  existed, Exporter would call C<require_version>.
  
  Since the C<UNIVERSAL::VERSION> method treats the C<$VERSION> number as
  a simple numeric value it will regard version 1.10 as lower than
  1.9.  For this reason it is strongly recommended that you use numbers
  with at least two decimal places, e.g., 1.09.
  
  =head2 Managing Unknown Symbols
  
  In some situations you may want to prevent certain symbols from being
  exported.  Typically this applies to extensions which have functions
  or constants that may not exist on some systems.
  
  The names of any symbols that cannot be exported should be listed
  in the C<@EXPORT_FAIL> array.
  
  If a module attempts to import any of these symbols the Exporter
  will give the module an opportunity to handle the situation before
  generating an error.  The Exporter will call an export_fail method
  with a list of the failed symbols:
  
    @failed_symbols = $module_name->export_fail(@failed_symbols);
  
  If the C<export_fail> method returns an empty list then no error is
  recorded and all the requested symbols are exported.  If the returned
  list is not empty then an error is generated for each symbol and the
  export fails.  The Exporter provides a default C<export_fail> method which
  simply returns the list unchanged.
  
  Uses for the C<export_fail> method include giving better error messages
  for some symbols and performing lazy architectural checks (put more
  symbols into C<@EXPORT_FAIL> by default and then take them out if someone
  actually tries to use them and an expensive check shows that they are
  usable on that platform).
  
  =head2 Tag Handling Utility Functions
  
  Since the symbols listed within C<%EXPORT_TAGS> must also appear in either
  C<@EXPORT> or C<@EXPORT_OK>, two utility functions are provided which allow
  you to easily add tagged sets of symbols to C<@EXPORT> or C<@EXPORT_OK>:
  
    our %EXPORT_TAGS = (foo => [qw(aa bb cc)], bar => [qw(aa cc dd)]);
  
    Exporter::export_tags('foo');     # add aa, bb and cc to @EXPORT
    Exporter::export_ok_tags('bar');  # add aa, cc and dd to @EXPORT_OK
  
  Any names which are not tags are added to C<@EXPORT> or C<@EXPORT_OK>
  unchanged but will trigger a warning (with C<-w>) to avoid misspelt tags
  names being silently added to C<@EXPORT> or C<@EXPORT_OK>.  Future versions
  may make this a fatal error.
  
  =head2 Generating Combined Tags
  
  If several symbol categories exist in C<%EXPORT_TAGS>, it's usually
  useful to create the utility ":all" to simplify "use" statements.
  
  The simplest way to do this is:
  
   our  %EXPORT_TAGS = (foo => [qw(aa bb cc)], bar => [qw(aa cc dd)]);
  
    # add all the other ":class" tags to the ":all" class,
    # deleting duplicates
    {
      my %seen;
  
      push @{$EXPORT_TAGS{all}},
        grep {!$seen{$_}++} @{$EXPORT_TAGS{$_}} foreach keys %EXPORT_TAGS;
    }
  
  F<CGI.pm> creates an ":all" tag which contains some (but not really
  all) of its categories.  That could be done with one small
  change:
  
    # add some of the other ":class" tags to the ":all" class,
    # deleting duplicates
    {
      my %seen;
  
      push @{$EXPORT_TAGS{all}},
        grep {!$seen{$_}++} @{$EXPORT_TAGS{$_}}
          foreach qw/html2 html3 netscape form cgi internal/;
    }
  
  Note that the tag names in C<%EXPORT_TAGS> don't have the leading ':'.
  
  =head2 C<AUTOLOAD>ed Constants
  
  Many modules make use of C<AUTOLOAD>ing for constant subroutines to
  avoid having to compile and waste memory on rarely used values (see
  L<perlsub> for details on constant subroutines).  Calls to such
  constant subroutines are not optimized away at compile time because
  they can't be checked at compile time for constancy.
  
  Even if a prototype is available at compile time, the body of the
  subroutine is not (it hasn't been C<AUTOLOAD>ed yet).  perl needs to
  examine both the C<()> prototype and the body of a subroutine at
  compile time to detect that it can safely replace calls to that
  subroutine with the constant value.
  
  A workaround for this is to call the constants once in a C<BEGIN> block:
  
     package My ;
  
     use Socket ;
  
     foo( SO_LINGER );  ## SO_LINGER NOT optimized away; called at runtime
     BEGIN { SO_LINGER }
     foo( SO_LINGER );  ## SO_LINGER optimized away at compile time.
  
  This forces the C<AUTOLOAD> for C<SO_LINGER> to take place before
  SO_LINGER is encountered later in C<My> package.
  
  If you are writing a package that C<AUTOLOAD>s, consider forcing
  an C<AUTOLOAD> for any constants explicitly imported by other packages
  or which are usually used when your package is C<use>d.
  
  =head1 Good Practices
  
  =head2 Declaring C<@EXPORT_OK> and Friends
  
  When using C<Exporter> with the standard C<strict> and C<warnings>
  pragmas, the C<our> keyword is needed to declare the package
  variables C<@EXPORT_OK>, C<@EXPORT>, C<@ISA>, etc.
  
    our @ISA = qw(Exporter);
    our @EXPORT_OK = qw(munge frobnicate);
  
  If backward compatibility for Perls B<under> 5.6 is important,
  one must write instead a C<use vars> statement.
  
    use vars qw(@ISA @EXPORT_OK);
    @ISA = qw(Exporter);
    @EXPORT_OK = qw(munge frobnicate);
  
  =head2 Playing Safe
  
  There are some caveats with the use of runtime statements
  like C<require Exporter> and the assignment to package
  variables, which can be very subtle for the unaware programmer.
  This may happen for instance with mutually recursive
  modules, which are affected by the time the relevant
  constructions are executed.
  
  The ideal way to never have to think about that is to use
  C<BEGIN> blocks and the simple import method.  So the first part
  of the L</SYNOPSIS> code could be rewritten as:
  
    package YourModule;
  
    use strict;
    use warnings;
  
    use Exporter 'import';
    BEGIN {
      our @EXPORT_OK = qw(munge frobnicate);  # symbols to export on request
    }
  
  Or if you need to inherit from Exporter:
  
    package YourModule;
  
    use strict;
    use warnings;
  
    BEGIN {
      require Exporter;
      our @ISA = qw(Exporter);  # inherit all of Exporter's methods
      our @EXPORT_OK = qw(munge frobnicate);  # symbols to export on request
    }
  
  The C<BEGIN> will assure that the loading of F<Exporter.pm>
  and the assignments to C<@ISA> and C<@EXPORT_OK> happen
  immediately like C<use>, leaving no room for something to get awry
  or just plain wrong.
  
  With respect to loading C<Exporter> and inheriting, there
  are alternatives with the use of modules like C<base> and C<parent>.
  
    use base qw(Exporter);
    # or
    use parent qw(Exporter);
  
  Any of these statements are nice replacements for
  C<BEGIN { require Exporter; our @ISA = qw(Exporter); }>
  with the same compile-time effect.  The basic difference
  is that C<base> code interacts with declared C<fields>
  while C<parent> is a streamlined version of the older
  C<base> code to just establish the IS-A relationship.
  
  For more details, see the documentation and code of
  L<base> and L<parent>.
  
  Another thorough remedy to that runtime
  vs. compile-time trap is to use L<Exporter::Easy>,
  which is a wrapper of Exporter that allows all
  boilerplate code at a single gulp in the
  use statement.
  
     use Exporter::Easy (
         OK => [ qw(munge frobnicate) ],
     );
     # @ISA setup is automatic
     # all assignments happen at compile time
  
  =head2 What Not to Export
  
  You have been warned already in L</Selecting What to Export>
  to not export:
  
  =over 4
  
  =item *
  
  method names (because you don't need to
  and that's likely to not do what you want),
  
  =item *
  
  anything by default (because you don't want to surprise your users...
  badly)
  
  =item *
  
  anything you don't need to (because less is more)
  
  =back
  
  There's one more item to add to this list.  Do B<not>
  export variable names.  Just because C<Exporter> lets you
  do that, it does not mean you should.
  
    @EXPORT_OK = qw($svar @avar %hvar); # DON'T!
  
  Exporting variables is not a good idea.  They can
  change under the hood, provoking horrible
  effects at-a-distance that are too hard to track
  and to fix.  Trust me: they are not worth it.
  
  To provide the capability to set/get class-wide
  settings, it is best instead to provide accessors
  as subroutines or class methods instead.
  
  =head1 SEE ALSO
  
  C<Exporter> is definitely not the only module with
  symbol exporter capabilities.  At CPAN, you may find
  a bunch of them.  Some are lighter.  Some
  provide improved APIs and features.  Pick the one
  that fits your needs.  The following is
  a sample list of such modules.
  
      Exporter::Easy
      Exporter::Lite
      Exporter::Renaming
      Exporter::Tidy
      Sub::Exporter / Sub::Installer
      Perl6::Export / Perl6::Export::Attrs
  
  =head1 LICENSE
  
  This library is free software.  You can redistribute it
  and/or modify it under the same terms as Perl itself.
  
  =cut
  
  
  
EXPORTER

$fatpacked{"Exporter/Heavy.pm"} = '#line '.(1+__LINE__).' "'.__FILE__."\"\n".<<'EXPORTER_HEAVY';
  package Exporter::Heavy;
  
  use strict;
  no strict 'refs';
  
  # On one line so MakeMaker will see it.
  our $VERSION = '5.77';
  
  =head1 NAME
  
  Exporter::Heavy - Exporter guts
  
  =head1 SYNOPSIS
  
  (internal use only)
  
  =head1 DESCRIPTION
  
  No user-serviceable parts inside.
  
  =cut
  
  #
  # We go to a lot of trouble not to 'require Carp' at file scope,
  #  because Carp requires Exporter, and something has to give.
  #
  
  sub _rebuild_cache {
      my ($pkg, $exports, $cache) = @_;
      s/^&// foreach @$exports;
      @{$cache}{@$exports} = (1) x @$exports;
      my $ok = \@{"${pkg}::EXPORT_OK"};
      if (@$ok) {
  	s/^&// foreach @$ok;
  	@{$cache}{@$ok} = (1) x @$ok;
      }
  }
  
  sub heavy_export {
  
      # Save the old __WARN__ handler in case it was defined
      my $oldwarn = $SIG{__WARN__};
  
      # First make import warnings look like they're coming from the "use".
      local $SIG{__WARN__} = sub {
  	# restore it back so proper stacking occurs
  	local $SIG{__WARN__} = $oldwarn;
  	my $text = shift;
  	if ($text =~ s/ at \S*Exporter\S*.pm line \d+.*\n//) {
  	    require Carp;
  	    local $Carp::CarpLevel = 1;	# ignore package calling us too.
  	    Carp::carp($text);
  	}
  	else {
  	    warn $text;
  	}
      };
      local $SIG{__DIE__} = sub {
  	require Carp;
  	local $Carp::CarpLevel = 1;	# ignore package calling us too.
  	Carp::croak("$_[0]Illegal null symbol in \@${1}::EXPORT")
  	    if $_[0] =~ /^Unable to create sub named "(.*?)::"/;
      };
  
      my($pkg, $callpkg, @imports) = @_;
      my($type, $sym, $cache_is_current, $oops);
      my($exports, $export_cache) = (\@{"${pkg}::EXPORT"},
                                     $Exporter::Cache{$pkg} ||= {});
  
      if (@imports) {
  	if (!%$export_cache) {
  	    _rebuild_cache ($pkg, $exports, $export_cache);
  	    $cache_is_current = 1;
  	}
  
  	if (grep m{^[/!:]}, @imports) {
  	    my $tagsref = \%{"${pkg}::EXPORT_TAGS"};
  	    my $tagdata;
  	    my %imports;
  	    my($remove, $spec, @names, @allexports);
  	    # negated first item implies starting with default set:
  	    unshift @imports, ':DEFAULT' if $imports[0] =~ m/^!/;
  	    foreach $spec (@imports){
  		$remove = $spec =~ s/^!//;
  
  		if ($spec =~ s/^://){
  		    if ($spec eq 'DEFAULT'){
  			@names = @$exports;
  		    }
  		    elsif ($tagdata = $tagsref->{$spec}) {
  			@names = @$tagdata;
  		    }
  		    else {
  			warn qq["$spec" is not defined in %${pkg}::EXPORT_TAGS];
  			++$oops;
  			next;
  		    }
  		}
  		elsif ($spec =~ m:^/(.*)/$:){
  		    my $patn = $1;
  		    @allexports = keys %$export_cache unless @allexports; # only do keys once
  		    @names = grep(/$patn/, @allexports); # not anchored by default
  		}
  		else {
  		    @names = ($spec); # is a normal symbol name
  		}
  
  		warn "Import ".($remove ? "del":"add").": @names "
  		    if $Exporter::Verbose;
  
  		if ($remove) {
  		   foreach $sym (@names) { delete $imports{$sym} } 
  		}
  		else {
  		    @imports{@names} = (1) x @names;
  		}
  	    }
  	    @imports = keys %imports;
  	}
  
          my @carp;
  	foreach $sym (@imports) {
  	    if (!$export_cache->{$sym}) {
  		if ($sym =~ m/^\d/) {
  		    $pkg->VERSION($sym); # inherit from UNIVERSAL
  		    # If the version number was the only thing specified
  		    # then we should act as if nothing was specified:
  		    if (@imports == 1) {
  			@imports = @$exports;
  			last;
  		    }
  		    # We need a way to emulate 'use Foo ()' but still
  		    # allow an easy version check: "use Foo 1.23, ''";
  		    if (@imports == 2 and !$imports[1]) {
  			@imports = ();
  			last;
  		    }
  		} elsif ($sym !~ s/^&// || !$export_cache->{$sym}) {
  		    # Last chance - see if they've updated EXPORT_OK since we
  		    # cached it.
  
  		    unless ($cache_is_current) {
  			%$export_cache = ();
  			_rebuild_cache ($pkg, $exports, $export_cache);
  			$cache_is_current = 1;
  		    }
  
  		    if (!$export_cache->{$sym}) {
  			# accumulate the non-exports
  			push @carp,
  			  qq["$sym" is not exported by the $pkg module];
  			$oops++;
  		    }
  		}
  	    }
  	}
  	if ($oops) {
  	    require Carp;
  	    Carp::croak(join("\n", @carp, "Can't continue after import errors"));
  	}
      }
      else {
  	@imports = @$exports;
      }
  
      my($fail, $fail_cache) = (\@{"${pkg}::EXPORT_FAIL"},
                                $Exporter::FailCache{$pkg} ||= {});
  
      if (@$fail) {
  	if (!%$fail_cache) {
  	    # Build cache of symbols. Optimise the lookup by adding
  	    # barewords twice... both with and without a leading &.
  	    # (Technique could be applied to $export_cache at cost of memory)
  	    my @expanded = map { /^\w/ ? ($_, '&'.$_) : $_ } @$fail;
  	    warn "${pkg}::EXPORT_FAIL cached: @expanded" if $Exporter::Verbose;
  	    @{$fail_cache}{@expanded} = (1) x @expanded;
  	}
  	my @failed;
  	foreach $sym (@imports) { push(@failed, $sym) if $fail_cache->{$sym} }
  	if (@failed) {
  	    @failed = $pkg->export_fail(@failed);
  	    foreach $sym (@failed) {
                  require Carp;
  		Carp::carp(qq["$sym" is not implemented by the $pkg module ],
  			"on this architecture");
  	    }
  	    if (@failed) {
  		require Carp;
  		Carp::croak("Can't continue after import errors");
  	    }
  	}
      }
  
      warn "Importing into $callpkg from $pkg: ",
  		join(", ",sort @imports) if $Exporter::Verbose;
  
      foreach $sym (@imports) {
  	# shortcut for the common case of no type character
  	(*{"${callpkg}::$sym"} = \&{"${pkg}::$sym"}, next)
  	    unless $sym =~ s/^(\W)//;
  	$type = $1;
  	no warnings 'once';
  	*{"${callpkg}::$sym"} =
  	    $type eq '&' ? \&{"${pkg}::$sym"} :
  	    $type eq '$' ? \${"${pkg}::$sym"} :
  	    $type eq '@' ? \@{"${pkg}::$sym"} :
  	    $type eq '%' ? \%{"${pkg}::$sym"} :
  	    $type eq '*' ?  *{"${pkg}::$sym"} :
  	    do { require Carp; Carp::croak("Can't export symbol: $type$sym") };
      }
  }
  
  sub heavy_export_to_level
  {
        my $pkg = shift;
        my $level = shift;
        (undef) = shift;			# XXX redundant arg
        my $callpkg = caller($level);
        $pkg->export($callpkg, @_);
  }
  
  # Utility functions
  
  sub _push_tags {
      my($pkg, $var, $syms) = @_;
      my @nontag = ();
      my $export_tags = \%{"${pkg}::EXPORT_TAGS"};
      push(@{"${pkg}::$var"},
  	map { $export_tags->{$_} ? @{$export_tags->{$_}} 
                                   : scalar(push(@nontag,$_),$_) }
  		(@$syms) ? @$syms : keys %$export_tags);
      if (@nontag and $^W) {
  	# This may change to a die one day
  	require Carp;
  	Carp::carp(join(", ", @nontag)." are not tags of $pkg");
      }
  }
  
  sub heavy_require_version {
      my($self, $wanted) = @_;
      my $pkg = ref $self || $self;
      return ${pkg}->VERSION($wanted);
  }
  
  sub heavy_export_tags {
    _push_tags((caller)[0], "EXPORT",    \@_);
  }
  
  sub heavy_export_ok_tags {
    _push_tags((caller)[0], "EXPORT_OK", \@_);
  }
  
  1;
EXPORTER_HEAVY

$fatpacked{"parent.pm"} = '#line '.(1+__LINE__).' "'.__FILE__."\"\n".<<'PARENT';
  package parent;
  use strict;
  
  our $VERSION = '0.241';
  
  sub import {
      my $class = shift;
  
      my $inheritor = caller(0);
  
      if ( @_ and $_[0] eq '-norequire' ) {
          shift @_;
      } else {
          for ( my @filename = @_ ) {
              s{::|'}{/}g;
              require "$_.pm"; # dies if the file is not found
          }
      }
  
      {
          no strict 'refs';
          push @{"$inheritor\::ISA"}, @_; # dies if a loop is detected
      };
  };
  
  1;
  
  __END__
  
  =encoding utf8
  
  =head1 NAME
  
  parent - Establish an ISA relationship with base classes at compile time
  
  =head1 SYNOPSIS
  
      package Baz;
      use parent qw(Foo Bar);
  
  =head1 DESCRIPTION
  
  Allows you to both load one or more modules, while setting up inheritance from
  those modules at the same time.  Mostly similar in effect to
  
      package Baz;
      BEGIN {
          require Foo;
          require Bar;
          push @ISA, qw(Foo Bar);
      }
  
  By default, every base class needs to live in a file of its own.
  If you want to have a subclass and its parent class in the same file, you
  can tell C<parent> not to load any modules by using the C<-norequire> switch:
  
    package Foo;
    sub exclaim { "I CAN HAS PERL" }
  
    package DoesNotLoadFooBar;
    use parent -norequire, 'Foo', 'Bar';
    # will not go looking for Foo.pm or Bar.pm
  
  This is equivalent to the following code:
  
    package Foo;
    sub exclaim { "I CAN HAS PERL" }
  
    package DoesNotLoadFooBar;
    push @DoesNotLoadFooBar::ISA, 'Foo', 'Bar';
  
  This is also helpful for the case where a package lives within
  a differently named file:
  
    package MyHash;
    use Tie::Hash;
    use parent -norequire, 'Tie::StdHash';
  
  This is equivalent to the following code:
  
    package MyHash;
    require Tie::Hash;
    push @ISA, 'Tie::StdHash';
  
  If you want to load a subclass from a file that C<require> would
  not consider an eligible filename (that is, it does not end in
  either C<.pm> or C<.pmc>), use the following code:
  
    package MySecondPlugin;
    require './plugins/custom.plugin'; # contains Plugin::Custom
    use parent -norequire, 'Plugin::Custom';
  
  =head1 HISTORY
  
  This module was forked from L<base> to remove the cruft
  that had accumulated in it.
  
  =head1 CAVEATS
  
  =head1 SEE ALSO
  
  =over 4
  
  =item L<base>
  
  =item L<parent::versioned>
  
  A fork of L<parent> that provides version checking in parent class modules.
  
  =back
  
  =head1 AUTHORS AND CONTRIBUTORS
  
  Rafaël Garcia-Suarez, Bart Lateur, Max Maischein, Anno Siegel, Michael Schwern
  
  =head1 MAINTAINER
  
  Max Maischein C< corion@cpan.org >
  
  Copyright (c) 2007-2017 Max Maischein C<< <corion@cpan.org> >>
  Based on the idea of C<base.pm>, which was introduced with Perl 5.004_04.
  
  =head1 LICENSE
  
  This module is released under the same terms as Perl itself.
  
  =cut
PARENT

s/^  //mg for values %fatpacked;

my $class = 'FatPacked::'.(0+\%fatpacked);
no strict 'refs';
*{"${class}::files"} = sub { keys %{$_[0]} };

if ($] < 5.008) {
  *{"${class}::INC"} = sub {
    if (my $fat = $_[0]{$_[1]}) {
      my $pos = 0;
      my $last = length $fat;
      return (sub {
        return 0 if $pos == $last;
        my $next = (1 + index $fat, "\n", $pos) || $last;
        $_ .= substr $fat, $pos, $next - $pos;
        $pos = $next;
        return 1;
      });
    }
  };
}

else {
  *{"${class}::INC"} = sub {
    if (my $fat = $_[0]{$_[1]}) {
      open my $fh, '<', \$fat
        or die "FatPacker error loading $_[1] (could be a perl installation issue?)";
      return $fh;
    }
    return;
  };
}

unshift @INC, bless \%fatpacked, $class;
  } # END OF FATPACK CODE

## no critic (ControlStructures::ProhibitPostfixControls)
## no critic (ValuesAndExpressions::ProhibitConstantPragma)
use strict;
use warnings;
use open ':std', IO => ':encoding(UTF-8)';

# ABSTRACT: Ensure that the environment variables match what you need, or abort.

# PODNAME: envassert

our $VERSION = '0.010'; # VERSION: generated by DZP::OurPkgVersion

use English      qw( -no_match_vars );                   # Avoids regex performance penalty in perl 5.18 and earlier
use Getopt::Long qw( :config auto_version auto_help );
use Carp;
use Pod::Usage;

use Env::Assert qw( :all );

local $OUTPUT_AUTOFLUSH = 1;

use constant {
    YEAR_START        => 1900,
    MONTH_START       => 1,
    ENV_DESC_FILENAME => '.envdesc',
    INDENT            => q{    },
};

my $man = 0;
my $break_at_first_error;
my $env_desc_filename = ENV_DESC_FILENAME;
my $exact;
GetOptions(
    'man'                     => \$man,
    'break-at-first-error|b!' => \$break_at_first_error,
    'env-description|e=s'     =>,
    \$env_desc_filename,
    'exact|x!' => \$exact,
) or pod2usage(2);
pod2usage( -exitval => 0, -verbose => 2 ) if $man;

sub main {

    open my $fh, q{<}, $env_desc_filename or croak "Cannot open file '$env_desc_filename'";
    my $env_desc_file = q{};
    my @env_desc_rows;
    while (<$fh>) { chomp; push @env_desc_rows, $_; }
    close $fh or croak "Cannot close file '$env_desc_filename'";

    my $desc = file_to_desc(@env_desc_rows);
    my %parameters;
    $parameters{'break_at_first_error'} = $break_at_first_error
      if defined $break_at_first_error;
    $desc->{'options'}->{'exact'} = $exact
      if defined $exact;
    my $r = assert( \%ENV, $desc, \%parameters );
    if ( !$r->{'success'} ) {
        print {*STDOUT} report_errors( $r->{'errors'} )
          or croak 'Cannot print errors to STDOUT';
        return 1;
    }
    return 0;
}

exit main(@ARGV);

__END__

=pod

=encoding UTF-8

=head1 NAME

envassert - Ensure that the environment variables match what you need, or abort.

=head1 VERSION

version 0.010

=head1 SYNOPSIS

envassert [options]

Options:
    --help
    --man
    --version
    --break-at-error
    --env-description

=head1 DESCRIPTION

B<envassert> checks that your runtime environment, as defined
with environment variables, matches with what you want.

You can define your required environment in a file.
Default file is F<.envassert> but you can use any file.

It is advantageous to use B<envassert> for examnple when running
a container. If you check your environment for missing or
wrongly defined environment variables at the beginning of
the container run, your container will fail sooner instead
of in a later point in execution when the variables are needed.

=head2 Errors

There are three kinds of errors:

=over 8

=item ENV_ASSERT_MISSING_FROM_ENVIRONMENT

"Variable <var_name> is missing from environment"

=item ENV_ASSERT_INVALID_CONTENT_IN_VARIABLE

"Variable <var_name> has invalid content"

=item ENV_ASSERT_MISSING_FROM_DEFINITION

"Variable <var_name> is missing from description"

This error will only be reported if you have set
the special option B<exact>. See below.

=back

=head2 Environment Description Language

Environment is described in file F<.envdesc>.
Environment description file is a Unix shell compatible file,
similar to a F<.env> file.

=head3 F<.envdesc> Format

In F<.envdesc> file there is only environment variables, comments
or empty rows.
Example:

    # Required env
    ## envassert (opts: exact=1)
    FILENAME=^[[:word:]]{1,}$

Env var name is followed by a regular expression. The regexp is
an extended Perl regular expression without quotation marks.
One env var and its descriptive regexp use one row.

A comment begins at the beginning of the row and uses the whole row.
It start with '#' character.

Two comment characters and the word B<envassert> at the beginning of the row
mean this is an B<envassert> meta command.
You can specify different environment related options with these commands.

Supported options:

=over 8

=item exact

The option I<exact> means that all allowed env variables
are described in this file. Any unknown env var causes an error
when verifying.

=back

=head2 CLI interface without dependencies

The F<envassert> command is also available
as self contained executable.
You can download it and run it as it is without
additional installation of CPAN packages.
Of course, you still need Perl, but Perl comes with any
normal Linux installation.

This can be convenient if you want to, for instance,
include F<envassert> in a docker container build.

    curl -LSs -o envassert https://raw.githubusercontent.com/mikkoi/env-assert/main/envassert.self-contained
    chmod +x ./envassert

=head1 OPTIONS

=over 8

=item B<--help>

Print a brief help message and exits.

=item B<--man>

Prints the manual page and exits.

=item B<--version>

Prints the version and exits.

=item B<-b>, B<--break-at-first-error>

Break checking at the first error and report back.
Default: false

=item B<-e>, B<--env-description>

Path to file which has the environment description.
Default: .envdesc

=item B<-x>, B<--exact>

Fail check if environment contains variables not defined in environment descript.
This option will override the equivalent option in .envdesc file.
Default: false

=back

=head1 EXAMPLES

    $ envassert
    Environment Assert: ERRORS:
        variables:
            FIRST_VAR: Variable FIRST_VAR is missing from environment
            FOURTH_VAR: Variable FOURTH_VAR is missing from environment

=head1 DEPENDENCIES

No external dependencies outside Perl's standard distribution.

=head1 AUTHOR

Mikko Koivunalho <mikkoi@cpan.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2023 by Mikko Koivunalho.

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

=cut