Provided by: pdl_2.007-2build1_amd64 
NAME
PDL::Options - simplifies option passing by hash in PerlDL
SYNOPSIS
use PDL::Options;
%hash = parse( \%defaults, \%user_options);
use PDL::Options ();
$opt = new PDL::Options;
$opt = new PDL::Options ( \%defaults );
$opt->defaults ( \%defaults );
$opt->synonyms ( { 'COLOR' => 'COLOUR' } );
$hashref = $opt->defaults;
$opt->options ( \%user_options );
$hashref = $opt->options;
$opt->incremental(1);
$opt->full_options(0);
DESCRIPTION
Object to simplify option passing for PerlDL subroutines. Allows you to merge a user
defined options with defaults. A simplified (non-OO) interface is provided.
Utility functions
ifhref
parse({Ext => 'TIF', ifhref($opt)});
just return the argument if it is a hashref otherwise return an empty hashref. Useful in
conjunction with parse to return just the default values if argument is not a hash ref
NON-OO INTERFACE
A simplified non-object oriented interface is provided. These routines are exported into
the callers namespace by default.
parse( \%defaults, \%user_options)
This will parse user options by using the defaults. The following settings are used
for parsing: The options are case-sensitive, a default synonym table is consulted (see
"Default Synonyms"), minimum-matching is turned on, and translation of values is not
performed.
A hash (not hash reference) containing the processed options is returned.
%options = parse( { LINE => 1, COLOUR => 'red'}, { COLOR => 'blue'});
iparse( \%defaults, \%user_options)
Same as "parse" but matching is case insensitive
Default Synonyms
The following default synonyms are available in the non-OO interface:
COLOR => COLOUR
COLOUR => COLOR
CENTER => CENTRE
CENTRE => CENTER
METHODS
The following methods are available to PDL::Options objects.
new()
Constructor. Creates the object. With an optional argument can also set the default
options.
extend (\%options)
This will copy the existing options object and extend it with the requested extra
options.
defaults( \%defaults )
Method to set or return the current defaults. The argument should be a reference to a
hash. The hash reference is returned if no arguments are supplied.
The current values are reset whenever the defaults are changed.
add_synonym (\%synonyms)
Method to add another synonym to an option set The argument should be a reference to a
hash.
add_translation (\%translation)
Method to add another translation rule to an option set. The argument should be a
reference to a hash.
synonyms( \%synonyms )
Method to set or return the current synonyms. The argument should be a reference to a
hash. The hash reference is returned if no arguments are supplied.
This allows you to provide alternate keywords (such as allowing 'COLOR' as an option
when your defaults uses 'COLOUR').
current
Returns the current state of the options. This is returned as a hash reference
(although it is not a reference to the actual hash stored in the object). If
full_options() is true the full options hash is returned, if full_options() is false
only the modified options are returned (as set by the last call to options()).
clear_current
This routine clears the 'state' of the "PDL::Options" object so that the next call to
current will return an empty list
translation
Provide translation of options to more specific values that are recognised by the
program. This allows, for example, the automatic translation of the string 'red' to
'#ff0000'.
This method can be used to setup the dictionary and is hash reference with the
following structure:
OPTIONA => {
'string1' => decode1,
'string2' => decode2
},
OPTIONB => {
's4' => decodeb1,
}
etc....
Where OPTION? corresponds to the top level option name as stored in the defaults array
(eg LINECOLOR) and the anonymous hashes provide the translation from string1 ('red')
to decode1 ('#ff0000').
An options string will be translated automatically during the main options()
processing if autotrans() is set to true. Else translation can be initiated by the
user using the translate() method.
incremental
Specifies whether the user defined options will be treated as additions to the current
state of the object (1) or modifications to the default values only (0).
Can be used to set or return this value. Default is false.
full_options
Governs whether a complete set of options is returned (ie defaults + expanded user
options), true, or if just the expanded user options are returned, false (ie the
values specified by the user).
This can be useful when you are only interested in the changes to the options rather
than knowing the full state. (For example, if defaults contains keys for COLOUR and
LINESTYLE and the user supplied a key of COL, you may simply be interested in the
modification to COLOUR rather than the state of LINESTYLE and COLOUR.)
Default is true.
casesens
Specifies whether the user defined options will be processed independent of case (0)
or not (1). Default is to be case insensitive.
Can be used to set or return this value.
minmatch
Specifies whether the user defined options will be minimum matched with the defaults
(1) or whether the user defined options should match the default keys exactly.
Defaults is true (1).
If a particular key matches exactly (within the constraints imposed bby case
sensitivity) this key will always be taken as correct even if others are similar. For
example COL would match COL and COLOUR but this implementation will always return COL
in this case (note that for CO it will return both COL and COLOUR and pick one at
random.
Can be used to set or return this value.
autotrans
Specifies whether the user defined options will be processed via the translate()
method immediately following the main options parsing. Default is to autotranslate
(1).
Can be used to set or return this value.
casesenstrans
Specifies whether the keys in the options hash will be matched insensitive of case (0)
during translation() or not (1). Default is to be case insensitive.
Can be used to set or return this value.
minmatchtrans
Specifies whether the keys in the options hash will be minimum matched during
translation(). Default is false (0).
If a particular key matches exactly (within the constraints imposed bby case
sensitivity) this key will always be taken as correct even if others are similar. For
example COL would match COL and COLOUR but this implementation will always return COL
in this case (note that for CO it will return both COL and COLOUR and pick one at
random.
Can be used to set or return this value.
warnonmissing
Turn on or off the warning message printed when an options is not in the options hash.
This can be convenient when a user passes a set of options that has to be parsed by
several different option objects down the line.
debug
Turn on or off debug messages. Default is off (0). Can be used to set or return this
value.
options
Takes a set of user-defined options (as a reference to a hash) and merges them with
the current state (or the defaults; depends on the state of incremental()).
The user-supplied keys will be compared with the defaults. Case sensitivity and
minimum matching can be configured using the mimatch() and casesens() methods.
A warning is raised if keys present in the user options are not present in the
defaults unless warnonmissing is set.
A reference to a hash containing the merged options is returned.
$merged = $opt->options( { COL => 'red', Width => 1});
The state of the object can be retrieved after this by using the current() method or
by using the options() method with no arguments. If full_options() is true, all
options are returned (options plus overrides), if full_options() is false then only
the modified options are returned.
Synonyms are supported if they have been configured via the synonyms() method.
translate
Translate the current option values (eg those set via the options() method) using the
provided translation().
This method updates the current state of the object and returns the updated options
hash as a reference.
$ref = $opt->translate;
EXAMPLE
Two examples are shown. The first uses the simplified interface and the second uses the
object-oriented interface.
Non-OO
use PDL::Options (':Func');
%options = parse( {
LINE => 1,
COLOUR => 'red',
},
{
COLOR => 'blue'
}
);
This will return a hash containg
%options = (
LINE => 1,
COLOUR => 'blue'
)
Object oriented
The following example will try to show the main points:
use PDL::Options ();
# Create new object and supply defaults
$opt = new PDL::Options( { Colour => 'red',
LineStyle => 'dashed',
LineWidth => 1
}
);
# Create synonyms
$opt->synonyms( { Color => 'Colour' } );
# Create translation dictionary
$opt->translation( { Colour => {
'blue' => '#0000ff',
'red' => '#ff0000',
'green'=> '#00ff00'
},
LineStyle => {
'solid' => 1,
'dashed' => 2,
'dotted' => 3
}
}
);
# Generate and parse test hash
$options = $opt->options( { Color => 'green',
lines => 'solid',
}
);
When this code is run, $options will be the reference to a hash containing the following:
Colour => '#00ff00',
LineStyle => 1,
LineWidth => 1
If full_options() was set to false (0), $options would be a reference to a hash
containing:
Colour => '#00ff00',
LineStyle => 1
Minimum matching and case insensitivity can be configured for both the initial parsing and
for the subsequent translating. The translation can be turned off if not desired.
Currently synonyms are not available for the translation although this could be added
quite simply.
AUTHOR
Copyright (C) Tim Jenness 1998 (t.jenness@jach.hawaii.edu). All rights reserved. There is
no warranty. You are allowed to redistribute this software / documentation under certain
conditions. For details, see the file COPYING in the PDL distribution. If this file is
separated from the PDL distribution, the copyright notice should be included in the file.