NAME
Data::Startup - startup options class, override, config methods
SYNOPSIS
######
# Subroutine interface
#
use Data::Startup qw(config override);
$options = override(\%default_options, @option_list );
$options = override(\%default_options, \@option_list );
$options = override(\%default_options, \%option_list );
@options_list = config(\%options );
($key, $old_value) = config(\%options, $key);
($key, $old_value) = config(\%options, $key => $new_value );
($key, $old_value) = config(\%options, $key => $new_value );
@old_options_list = config(\%options, @option_list);
@old_options_list = config(\%options, \@option_list);
@old_options_list = config(\%options, \%option_list);
######
# Object interface
#
use Data::Startup
$startup_options = $class->Data::Startup::new( @option_list );
$startup_options = $class->Data::Startup::new( \@option_list );
$startup_options = $class->Data::Startup::new( \%option_list );
$options = $startup_options->override( @option_list );
$options = $startup_options->override( \@option_list );
$options = $startup_options->override( \%option_list );
@options_list = $options->config( );
($key, $old_value) = $options->config($key);
($key, $old_value) = $options->config($key => $new_value );
($key, $old_value) = $options->config($key => $new_value );
@old_options_list = $options->config(@option_list);
@old_options_list = $options->config(\@option_list);
@old_options_list = $options->config(\%option_list);
# Note: May use [@option_list] instead of \@option_list
# and {@option_list} instead of \%option_listDESCRIPTION
Many times there is a group of subroutines that can be tailored by different situations with a few, say global variables. However, global variables pollute namespaces, become mangled when the functions are multi-threaded and probably have many other faults that it is not worth the time discovering.
As well documented in literature, object oriented programming do not have these faults. This program module class of objects provide the objectized options for a group of subroutines or encapsulated options by using the methods directly as in an option object.
The Data::Startup class provides a way to input options in very liberal manner of either
arrays, reference to an array, or reference to hash to a
reference to an array or reference to a hash
reference to a hash
referene to an array
many other combos
without having to cut and paste specialize, tailored code into each subroutine/method.
Some of the possiblities follows.
A subroutine may be utilize either as a subroutine or a method of a object by processing the first argument of @_ by the following:
sub my_suroutine
{
shift if UNIVERSAL::isa($_[0],__PACKAGE__);
# ....
}The Data::Startup class may be used to provide various options syntax for a dual methods/subroutines as follows:
my $default_options = new( @default_options_list);
# SYNTAX: my_subroutine1($arg1 .. $argn, @options)
# my_subroutine1($arg1 .. $argn, \@options)
# my_subroutine1($arg1 .. $argn, \%options)
#
sub my_subroutine1
{
shift if UNIVERSAL::isa($_[0],__PACKAGE__);
$default_options = Data::Startup->new() unless $default_options;
my ($arg1 .. $argn, @options) = @_
my $options = $default_options->override(@options);
# ....
}
# SYNTAX: my_subroutine2(\@options, @args)
# my_subroutine2(\%options, @args)
#
# !ref($args[0])
sub my_subroutine2
{
shift if UNIVERSAL::isa($_[0],__PACKAGE__);
$default_options = Data::Startup->new() unless $default_options;
my $options = $default_options->override(shift @_) if ref($_[0]);
# ....
}
# SYNTAX: my_subroutine3(\%options, @args)
#
# ref($args[0]) ne 'HASH'
sub my_subroutine3
{
shift if UNIVERSAL::isa($_[0],__PACKAGE__);
$default_options = Data::Startup->new() unless $default_options;
my $options = $default_options->override(shift @_) if ref($_[0] eq 'HASH');
my (@args) = @_;
# ....
}If program module does not require program module wide global default options, than still use Data::Startup to provide liberal options syntax as follows
# SYNTAX: my_subroutine1($arg1 .. $argn, @options)
# my_subroutine1($arg1 .. $argn, \@options)
# my_subroutine1($arg1 .. $argn, \%options)
#
sub my_subroutine4
{
shift if UNIVERSAL::isa($_[0],__PACKAGE__);
my ($arg1 .. $argn, @options) = @_
my $options = new Data::Startup(@options);
# ....
}This technique may be extended to many more different subroutine with a similar style syntax.
The Data::Startup class may be used may also be used to create objects off a base $default_object as follows:
use Data_Startup;
unshift @ISA,'Data_Startup'; # first among classes
use vars qw($default_object);
$default_object = new Data::Startup( @default_list);
sub new
{
$default_options->override( @_ );
}
my $object = new my_package;
my @old_options = object->config( @_ );
my @old_default_options = $my_package::$default_object->config( @_ );
sub method
{
$self = shift;
$value1 = $self->{$key1};
}And then there are the hybrid subroutine, class syntax and probably some other possibilies that are not readily apparent.
METHODS
new
The new method c<bless> the input @option_list creating a default options hash object.
config
The config method reads and writes individual key,value pairs or groups of key,value pairs in the $option object.
The method response with no inputs with all the $key,$value pairs in $options; a single $key input with the $key,$value for that $key; and, a group of $key, $value pairs, @option_list by replacing all the $option $key in the group by the paired <$value> returning the @old_options_list of old $key,$value pairs. The config method does not care if the @option_list is an array, a reference to an array or a reference to a hash.
override
The override method takes a default options object, $startup_options, creates a new duplicate object, $options, keeping $startup_options intact, and replaces selected optioins in $options with override values, @option_list.
REQUIREMENTS
Coming.
DEMONSTRATION
#########
# perl Startup.d
###~~~~~~ Demonstration overview ~~~~~
The results from executing the Perl Code follow on the next lines as comments. For example,
2 + 2
# 4~~~~~~ The demonstration follows ~~~~~
use File::Package;
my $uut = 'Data::Startup';
my ($result,@result); # provide scalar and array context
my ($default_options,$options) = ('$default_options','$options');
##################
# create a Data::Startup default options
#
($default_options = new $uut(
perl_secs_numbers => 'multicell',
type => 'ascii',
indent => '',
'Data::SecsPack' => {}
))
# bless( {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {},
# 'type' => 'ascii',
# 'indent' => ''
# }, 'Data::Startup' )
#
##################
# read perl_secs_numbers default option
#
[$default_options->config('perl_secs_numbers')]
# [
# 'perl_secs_numbers',
# 'multicell'
# ]
#
##################
# write perl_secs_numbers default option
#
[$default_options->config(perl_secs_numbers => 'strict')]
# [
# 'perl_secs_numbers',
# 'multicell'
# ]
#
##################
# restore perl_secs_numbers default option
#
[$default_options->config(perl_secs_numbers => 'multicell')]
# [
# 'perl_secs_numbers',
# 'strict'
# ]
#
##################
# create options copy of default options
#
$options = $default_options->override(type => 'binary')
# bless( {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {},
# 'type' => 'binary',
# 'indent' => ''
# }, 'Data::Startup' )
#
##################
# verify default options unchanged
#
$default_options
# bless( {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {},
# 'type' => 'ascii',
# 'indent' => ''
# }, 'Data::Startup' )
#
##################
# array reference option config
#
[@result = $options->config([perl_secs_numbers => 'strict'])]
# [
# 'perl_secs_numbers',
# 'multicell'
# ]
#
##################
# array reference option config
#
$options
# bless( {
# 'perl_secs_numbers' => 'strict',
# 'Data::SecsPack' => {},
# 'type' => 'binary',
# 'indent' => ''
# }, 'Data::Startup' )
#
##################
# hash reference option config
#
[@result = $options->config({'Data::SecsPack'=> {decimal_fraction_digits => 30} })]
# [
# 'Data::SecsPack',
# {}
# ]
#
##################
# hash reference option config
#
$options
# bless( {
# 'perl_secs_numbers' => 'strict',
# 'Data::SecsPack' => {
# 'decimal_fraction_digits' => 30
# },
# 'type' => 'binary',
# 'indent' => ''
# }, 'Data::Startup' )
#
##################
# verify default options still unchanged
#
$default_options
# bless( {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {},
# 'type' => 'ascii',
# 'indent' => ''
# }, 'Data::Startup' )
#
##################
# create a hash default options
#
my %default_hash = (
perl_secs_numbers => 'multicell',
type => 'ascii',
indent => '',
'Data::SecsPack' => {}
);
$default_options = \%default_hash
# {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {},
# 'type' => 'ascii',
# 'indent' => ''
# }
#
##################
# override default_hash with an option array
#
Data::Startup::override($default_options, type => 'binary')
# {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {},
# 'type' => 'binary',
# 'indent' => ''
# }
#
##################
# override default_hash with a reference to a hash
#
Data::Startup::override($default_options, {'Data::SecsPack'=> {decimal_fraction_digits => 30}})
# {
# 'perl_secs_numbers' => 'multicell',
# 'Data::SecsPack' => {
# 'decimal_fraction_digits' => 30
# },
# 'type' => 'ascii',
# 'indent' => ''
# }
#
##################
# override default_hash with a reference to an array
#
Data::Startup::override($default_options, [perl_secs_numbers => 'strict'])
# {
# 'perl_secs_numbers' => 'strict',
# 'Data::SecsPack' => {},
# 'type' => 'ascii',
# 'indent' => ''
# }
#
##################
# return from config default_hash with a reference to an array
#
[@result = Data::Startup::config($default_options, [perl_secs_numbers => 'strict'])]
# [
# 'perl_secs_numbers',
# 'multicell'
# ]
#
##################
# default_hash from config default_hash with a reference to an array
#
$default_options
# {
# 'perl_secs_numbers' => 'strict',
# 'Data::SecsPack' => {},
# 'type' => 'ascii',
# 'indent' => ''
# }
#QUALITY ASSURANCE
Running the test script Startup.t verifies the requirements for this module. The tmake.pl cover script for Test::STDmaker automatically generated the Startup.t test script, Startup.d demo script, and t::Data::Startup program module POD, from the t::Data::Startup program module contents. The tmake.pl cover script automatically ran the Startup.d demo script and inserted the results into the 'DEMONSTRATION' section above. The t::Data::Startup program module is in the distribution file Data-Startup-$VERSION.tar.gz.
NOTES
Author
The holder of the copyright and maintainer is
<support@SoftwareDiamonds.com>
Copyright Notice
Copyrighted (c) 2002 Software Diamonds
All Rights Reserved
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License
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