Config::INI::Writer(3)

NAME
Config::INI::Writer - a subclassable .ini-file emitter

VERSION
version 0.019

SYNOPSIS
If <$hash> contains:

  {
    '_'  => { admin => 'rjbs' },
    rjbs => {
      awesome => 'yes',
      height  => q{5' 10"},
    },
    mj   => {
      awesome => 'totally',
      height  => '23"',
    },
  }

Then when your program contains:

  Config::INI::Writer->write_file($hash, 'family.ini');

family.ini will contains:

  admin = rjbs

  [rjbs]
  awesome = yes
  height = 5' 10"

  [mj]
  awesome = totally
  height = 23"

DESCRIPTION
Config::INI::Writer is yet another config module implementing yet another slightly different take on the undeniably easy to read ".ini" file format. Its default behavior is quite similar to that of Config::Tiny, on which it is based.

The chief difference is that Config::INI::Writer is designed to be subclassed to allow for side-effects and self-reconfiguration to occur during the course of reading its input.

METHODS FOR WRITING CONFIG
There are three writer methods, "write_string", "write_file", and "write_handle". The first two are implemented in terms of the third. It iterates over a collection of data, emitting lines to the filehandle as it goes. The lines are generated by events produced by iterating over the data. Those events are detailed below in the "METHODS FOR SUBCLASSING" section.

The given data should be a hashref of hashrefs:

  {
    section_name_1 => { prop1 => 'value1', prop2 => 'value2' },
    section_name_2 => ...
  }

...or an arrayref of section name and arrayref pairs:

  [
    section_name_1 => [ prop1 => 'value1', prop2 => 'value2' ],
    section_name_2 => ...
  ]

...or a combination of those:

  [
    section_name_1 => { prop1 => 'value1', prop2 => 'value2' },
    section_name_2 => [ prop3 => 'value3', prop4 => 'value4' ],
    section_name_3 => ...
  ]

All the reader methods throw an exception when they encounter an error.

  write_file
  Config::INI::Writer->write_file($input, $filename);

This method writes out the configuration represented by $data to the file named by $filename. If a file by that name exists, it is overwritten.

This method will either succeed or raise an exception. (Its return value is not defined.)

  write_string
  my $string = Config::INI::Writer->write_string($input);

This method returns a string containing the INI content describing the given data.

  write_handle
  Config::INI::Writer->write_handle($input, $handle);

This method writes the data in $data to the IO::Handle-like object in $handle. This method should either succeed or throw an exception.

METHODS FOR SUBCLASSING
These are the methods you need to understand and possibly change when subclassing Config::INI::Reader to handle a different format of input.

  preprocess_input
  my $processed_input = $writer->preprocess_input($input_data);

This method is called to ensure that the data given to the "write_*" methods are in a canonical form for processing and emitting. The default implementation converts hashrefs to arrayrefs and, if the input is a hashref, moves the "starting_section" to the beginning of the produced arrayref.

In other words, given:

  {
    section_1 => { a => 1, b => 2 },
    section_2 => { c => 3, c => 4 },
    _         => { d => 5, e => 6 },
  }

This method will return:

  [
    _         => [ d => 5, e => 6 ],
    section_2 => [ c => 3, c => 4 ],
    section_1 => [ a => 1, b => 2 ],
  ]

The only guaranteed ordering when hashes are provided as input is that the starting section will appear first.

  validate_input
  $writer->validate_input($input);

This method is called on the input data once they've been preprocessed by "preprocess_input".

It ensures that the processed input is structurally sound before beginning to output it. For example, it ensures that no property is ever assigned more than once in a given section.

This method either raises an exception or it doesn't.

  change_section
  $writer->change_section($section_name);

This method is called each time a new section is going to be written out. If the same section appears twice in a row in the input, this method will still be called between instances of that section.

In other words, given this input:

  [
    section_1 => [ a => 1 ],
    section_1 => [ b => 2 ],
  ]

"change_section" will be called twice: once before the first "section_1" and once before the second "section_1".

  current_section
  $writer->current_section

This method returns the section currently being written out.

  finish_section
  $writer->finish_section

This method is called after all of the current section's properties have been written.

  done_sections
  my @names = $writer->done_sections;

This method returns a list of all sections that have been written out and finished. The fact that a section name is returned by "done_sections" does not mean that there will be no more data for that section, but that at least one entire set of data has been written out for it.

  stringify_section
  my $string = $writer->stringify_section($props);

This method returns a string assigning all the properties set in the given data. This still will include the section header, if needed. (The only case in which it is not needed is when the "explicit_starting_header" method returns false, no other sections have been done, and the section about to be stringified is the "starting_section".

This method is implemented in terms of "stringify_section_header" and "stringify_section_data".

  stringify_section_data
  my $string = $writer->stringify_section_data($props)

This method returns a string containing a series of lines, each containing a value assignment for the given properties.

  stringify_value_assignment
  my $string = $writer->stringify_value_assignment($name => $value);

This method returns a string that assigns a value to a named property. If the value is undefined, an empty string is returned.

  stringify_value
  my $string = $writer->stringify_value($value);

This method returns the string that will represent the given value in a property assignment.

  stringify_section_header
  my $string = $writer->stringify_section_header($section_name);

This method returns the string (a line) that represents the given section name. Basically, this returns:

  [section_name]

  starting_section
This method returns the name of the starting section. If this section appears first (as it will, when given a hashref as input) and if "explicit_starting_header" returns false, its section header can be omitted.

  explicit_starting_header
If this method returns true (which it does not, by default), then the section header for the starting section will be emitted, even if it appears first.

  new
  my $reader = Config::INI::Writer->new;

This method returns a new writer. This generally does not need to be called by anything but the various "write_*" methods, which create a writer object only ephemerally.

AUTHOR
Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE
This software is copyright (c) 2007 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.