Provided by: pdl_2.007-5_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.