NAME

       Config::MVP::Assembler - multivalue-property config-loading state machine

VERSION

       version 2.200013

DESCRIPTION

       First, you should probably read the example of using Config::MVP.  If you already know how
       it works, keep going.

       Config::MVP::Assembler is a helper for constructing a Config::MVP::Sequence object.  It's
       a very simple state machine that lets you signal what kind of events you've encountered
       while reading configuration.

PERL VERSION

       This module should work on any version of perl still receiving updates from the Perl 5
       Porters.  This means it should work on any version of perl released in the last two to
       three years.  (That is, if the most recently released version is v5.40, then this module
       should work on both v5.40 and v5.38.)

       Although it may work on older versions of perl, no guarantee is made that the minimum
       required version will not be increased.  The version may be increased for any reason, and
       there is no promise that patches will be accepted to lower the minimum required perl.

ATTRIBUTES

   sequence_class
       This attribute stores the name of the class to be used for the assembler's sequence.  It
       defaults to Config::MVP::Sequence.

   section_class
       This attribute stores the name of the class to be used for sections created by the
       assembler.  It defaults to Config::MVP::Section.

   sequence
       This is the sequence that the assembler is assembling.  It defaults to a new instance of
       the assembler's "sequence_class".

METHODS

   begin_section
         $assembler->begin_section($package_moniker, $name);

         $assembler->begin_section($package_moniker);

         $assembler->begin_section( \$package );

       This method tells the assembler that it should begin work on a new section with the given
       identifier.  If it is already working on a section, an error will be raised.  See
       "change_section" for a method to begin a new section, ending the current one if needed.

       The package moniker is expanded by the "expand_package" method.  The name, if not given,
       defaults to the package moniker.  These data are used to create a new section and the
       section is added to the end of the sequence.  If the package argument is a reference, it
       is used as the literal value for the package, and no expansion is performed.  If it is a
       reference to undef, a section with no package is created.

   end_section
         $assembler->end_section;

       This ends the current section.  If there is no current section, an exception is raised.

   change_section
         $assembler->change_section($package_moniker, $name);

         $assembler->change_section($package_moniker);

       This method calls "begin_section", first calling "end_section" if needed.

   add_value
         $assembler->add_value( $name => $value );

       This method tells the assembler that it has encountered a named value and should add it to
       the current section.  If there is no current section, an exception is raised.  (If this is
       not the first time we've seen the name in the section and it's not a multivalue property,
       the section class will raise an exception on its own.)

   expand_package
       This method is passed a short identifier for a package and is expected to return the full
       name of the module to load and package to interrogate.  By default it simply returns the
       name it was passed, meaning that package names must be given whole to the "change_section"
       method.

   current_section
       This returns the section object onto which the assembler is currently adding values.  If
       no section has yet been created, this method will return false.

TYPICAL USE

         my $assembler = Config::MVP::Assembler->new;

         # Maybe you want a starting section:
         my $starting_section = $assembler->section_class->new({ name => '_' });
         $assembler->sequence->add_section($section_starting);

         # We'll add some values, which will go to the starting section:
         $assembler->add_value(x => 10);
         $assembler->add_value(y => 20);

         # Change to a new section...
         $assembler->change_section($moniker);

         # ...and add values to that section.
         $assembler->add_value(x => 100);
         $assembler->add_value(y => 200);

       The code above creates an assembler and populates it step by step.  In the end, to get
       values, you could do something like this:

         my @output;

         for my $section ($assembler->sequence->sections) {
           push @output, [ $section->name, $section->package, $section->payload ];
         }

       When changing sections, the given section "moniker" is used for the new section name.  The
       result of passing that moniker to the assembler's "expand_package" method is used as the
       section's package name.  (By default, this method does nothing.)  The new section's
       "multivalue_args" and "aliases" are determined by calling the "mvp_multivalue_args" and
       "mvp_aliases" methods on the package.

AUTHOR

       Ricardo Signes <cpan@semiotic.systems>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2022 by Ricardo Signes.

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