NAME

       AppConfig::File - Perl5 module for reading configuration files.

SYNOPSIS

           use AppConfig::File;

           my $state   = AppConfig::State->new(\%cfg1);
           my $cfgfile = AppConfig::File->new($state, $file);

           $cfgfile->parse($file);            # read config file

OVERVIEW

       AppConfig::File is a Perl5 module which reads configuration files and use the contents
       therein to update variable values in an AppConfig::State object.

       AppConfig::File is distributed as part of the AppConfig bundle.

DESCRIPTION

   USING THE AppConfig::File MODULE
       To import and use the AppConfig::File module the following line should appear in your Perl
       script:

           use AppConfig::File;

       AppConfig::File is used automatically if you use the AppConfig module and create an
       AppConfig::File object through the file() method.

       AppConfig::File is implemented using object-oriented methods.  A new AppConfig::File
       object is created and initialised using the AppConfig::File->new() method.  This returns a
       reference to a new AppConfig::File object.  A reference to an AppConfig::State object
       should be passed in as the first parameter:

           my $state   = AppConfig::State->new();
           my $cfgfile = AppConfig::File->new($state);

       This will create and return a reference to a new AppConfig::File object.

   READING CONFIGURATION FILES
       The "parse()" method is used to read a configuration file and have the contents update the
       STATE accordingly.

           $cfgfile->parse($file);

       Multiple files maye be specified and will be read in turn.

           $cfgfile->parse($file1, $file2, $file3);

       The method will return an undef value if it encounters any errors opening the files.  It
       will return immediately without processing any further files.  By default, the PEDANTIC
       option in the AppConfig::State object, $self->{ STATE }, is turned off and any parsing
       errors (invalid variables, unvalidated values, etc) will generated warnings, but not cause
       the method to return.  Having processed all files, the method will return 1 if all files
       were processed without warning or 0 if one or more warnings were raised.  When the
       PEDANTIC option is turned on, the method generates a warning and immediately returns a
       value of 0 as soon as it encounters any parsing error.

       Variables values in the configuration files may be expanded depending on the value of
       their EXPAND option, as determined from the App::State object.  See AppConfig::State for
       more information on variable expansion.

   CONFIGURATION FILE FORMAT
       A configuration file may contain blank lines and comments which are ignored.  Comments
       begin with a '#' as the first character on a line or following one or more whitespace
       tokens, and continue to the end of the line.

           # this is a comment
           foo = bar               # so is this
           url = index.html#hello  # this too, but not the '#welcome'

       Notice how the '#welcome' part of the URL is not treated as a comment because a whitespace
       character doesn't precede it.

       Long lines can be continued onto the next line by ending the first line with a '\'.

           callsign = alpha bravo camel delta echo foxtrot golf hipowls \
                      india juliet kilo llama mike november oscar papa  \
                      quebec romeo sierra tango umbrella victor whiskey \
                      x-ray yankee zebra

       Variables that are simple flags and do not expect an argument (ARGCOUNT = ARGCOUNT_NONE)
       can be specified without any value.  They will be set with the value 1, with any value
       explicitly specified (except "0" and "off") being ignored.  The variable may also be
       specified with a "no" prefix to implicitly set the variable to 0.

           verbose                              # on  (1)
           verbose = 1                          # on  (1)
           verbose = 0                          # off (0)
           verbose off                          # off (0)
           verbose on                           # on  (1)
           verbose mumble                       # on  (1)
           noverbose                            # off (0)

       Variables that expect an argument (ARGCOUNT = ARGCOUNT_ONE) will be set to whatever
       follows the variable name, up to the end of the current line.  An equals sign may be
       inserted between the variable and value for clarity.

           room = /home/kitchen
           room   /home/bedroom

       Each subsequent re-definition of the variable value overwrites the previous value.

           print $config->room();               # prints "/home/bedroom"

       Variables may be defined to accept multiple values (ARGCOUNT = ARGCOUNT_LIST).  Each
       subsequent definition of the variable adds the value to the list of previously set values
       for the variable.

           drink = coffee
           drink = tea

       A reference to a list of values is returned when the variable is requested.

           my $beverages = $config->drinks();
           print join(", ", @$beverages);      # prints "coffee, tea"

       Variables may also be defined as hash lists (ARGCOUNT = ARGCOUNT_HASH).  Each subsequent
       definition creates a new key and value in the hash array.

           alias l="ls -CF"
           alias h="history"

       A reference to the hash is returned when the variable is requested.

           my $aliases = $config->alias();
           foreach my $k (keys %$aliases) {
               print "$k => $aliases->{ $k }\n";
           }

       A large chunk of text can be defined using Perl's "heredoc" quoting style.

          scalar = <<BOUNDARY_STRING
          line 1
          line 2: Space/linebreaks within a HERE document are kept.
          line 3: The last linebreak (\n) is stripped.
          BOUNDARY_STRING

          hash   key1 = <<'FOO'
            * Quotes (['"]) around the boundary string are simply ignored.
            * Whether the variables in HERE document are expanded depends on
              the EXPAND option of the variable or global setting.
          FOO

          hash = key2 = <<"_bar_"
          Text within HERE document are kept as is.
          # comments are treated as a normal text.
          The same applies to line continuation. \
          _bar_

       Note that you cannot use HERE document as a key in a hash or a name of a variable.

       The '-' prefix can be used to reset a variable to its default value and the '+' prefix can
       be used to set it to 1

           -verbose
           +debug

       Variable, environment variable and tilde (home directory) expansions Variable values may
       contain references to other AppConfig variables, environment variables and/or users' home
       directories.  These will be expanded depending on the EXPAND value for each variable or
       the GLOBAL EXPAND value.

       Three different expansion types may be applied:

           bin = ~/bin          # expand '~' to home dir if EXPAND_UID
           tmp = ~abw/tmp       # as above, but home dir for user 'abw'

           perl = $bin/perl     # expand value of 'bin' variable if EXPAND_VAR
           ripl = $(bin)/ripl   # as above with explicit parens

           home = ${HOME}       # expand HOME environment var if EXPAND_ENV

       See AppConfig::State for more information on expanding variable values.

       The configuration files may have variables arranged in blocks.  A block header, consisting
       of the block name in square brackets, introduces a configuration block.  The block name
       and an underscore are then prefixed to the names of all variables subsequently referenced
       in that block.  The block continues until the next block definition or to the end of the
       current file.

           [block1]
           foo = 10             # block1_foo = 10

           [block2]
           foo = 20             # block2_foo = 20

AUTHOR

       Andy Wardley, <abw@wardley.org>

COPYRIGHT

       Copyright (C) 1997-2007 Andy Wardley.  All Rights Reserved.

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

SEE ALSO

       AppConfig, AppConfig::State