#============================================================= -*-Perl-*-
#
# Template::Plugin::Datafile
#
# DESCRIPTION
#
#   Template Toolkit Plugin which reads a datafile and constructs a 
#   list object containing hashes representing records in the file.
#
# AUTHOR
#   Andy Wardley   <abw@kfs.org>
#
# COPYRIGHT
#   Copyright (C) 1996-2000 Andy Wardley.  All Rights Reserved.
#   Copyright (C) 1998-2000 Canon Research Centre Europe Ltd.
#
#   This module is free software; you can redistribute it and/or
#   modify it under the same terms as Perl itself.
#
#----------------------------------------------------------------------------
#
# $Id: Datafile.pm,v 2.3 2000/11/14 15:54:58 abw Exp $
#
#============================================================================

package Template::Plugin::Datafile;

require 5.004;

use strict;
use vars qw( @ISA $VERSION );
use base qw( Template::Plugin );
use Template::Plugin;

$VERSION = sprintf("%d.%02d", q$Revision: 2.3 $ =~ /(\d+)\.(\d+)/);

sub new {
    my ($class, $context, $filename, $params) = @_;
    my ($delim, $line, @fields, @data, @results);
    my $self = [ ];
    local *FD;
    local $/ = "\n";

    $params ||= { };
    $delim = $params->{'delim'} || ':';
    $delim = quotemeta($delim);

    return $class->fail("No filename specified")
	unless $filename;

    open(FD, $filename)
	|| return $class->fail("$filename: $!");

    # first line of file should contain field definitions
    while (! $line || $line =~ /^#/) {
	$line = <FD>;
	chomp $line;
    }
    (@fields = split(/\s*$delim\s*/, $line)) 
	|| return $class->fail("first line of file must contain field names");

    # read each line of the file
    while (<FD>) {
	chomp;

	# ignore comments and blank lines
	next if /^#/ || /^\s*$/;

	# split line into fields
	@data = split(/\s*$delim\s*/);

	# create hash record to represent data
	my %record;
	@record{ @fields } = @data;

	push(@$self, \%record);
    }

#    return $self;
    bless $self, $class;
}	


sub as_list {
    return $_[0];
}


1;


__END__

=head1 NAME

Template::Plugin::Datafile - plugin to construct records from a simple data file

=head1 SYNOPSIS

    [% USE mydata = datafile('/path/to/datafile') %]
    [% USE mydata = datafile('/path/to/datafile', delim = '|') %]
   
    [% FOREACH record = mydata %]
       [% record.this %]  [% record.that %]
    [% END %]

=head1 DESCRIPTION

This plugin provides a simple facility to construct a list of hash 
references, each of which represents a data record of known structure,
from a data file.

    [% USE datafile(filename) %]

A absolute filename must be specified (for this initial implementation at 
least - in a future version it might also use the INCLUDE_PATH).  An 
optional 'delim' parameter may also be provided to specify an alternate
delimiter character.

    [% USE userlist = datafile('/path/to/file/users')     %]
    [% USE things   = datafile('items', delim = '|') %]

The format of the file is intentionally simple.  The first line
defines the field names, delimited by colons with optional surrounding
whitespace.  Subsequent lines then defines records containing data
items, also delimited by colons.  e.g.

    id : name : email : tel
    abw : Andy Wardley : abw@cre.canon.co.uk : 555-1234
    neilb : Neil Bowers : neilb@cre.canon.co.uk : 555-9876

Each line is read, split into composite fields, and then used to 
initialise a hash array containing the field names as relevant keys.
The plugin returns a blessed list reference containing the hash 
references in the order as defined in the file.

    [% FOREACH user = userlist %]
       [% user.id %]: [% user.name %]
    [% END %]

The first line of the file B<must> contain the field definitions.
After the first line, blank lines will be ignored, along with comment
line which start with a '#'.

=head1 BUGS

Should handle file names relative to INCLUDE_PATH.
Doesn't permit use of ':' in a field.  Some escaping mechanism is required.

=head1 AUTHOR

Andy Wardley E<lt>kfs.orgE<gt>

=head1 REVISION

$Revision: 2.3 $

=head1 COPYRIGHT

Copyright (C) 1996-1999 Andy Wardley.  All Rights Reserved.
Copyright (C) 1998-1999 Canon Research Centre Europe Ltd.

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

=head1 SEE ALSO

L<Template::Plugin|Template::Plugin>, 

=cut