PDL::Options ------------ This module provides generalised option handling for PDL. It allows a hash of default values to be merged with a hash of options allowing for case insensitivty, minimum matching of hash keywords, support for synonyms (eg Color and Colour) and translation of values to standard form (eg 'blue' can be translated to '#0000ff'). This module is distributed as part of PDL (perl data language, http://pdl.perl.org) also available on CPAN. It has been extracted from PDL becuase it is felt that it could be of use to the general perl community and is required by some other modules on CPAN (eg Chart::XMGR). Building and installation ------------------------- This module follows the standard CPAN rules for building and installation: % perl Makefile.PL % make % make test % make install 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. POD documentation ----------------- NAME PDL::Options - simplifies option passing by hash in PerlDL SYNOPSIS use PDL::Options; $hashref = 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. 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 can be case-insensitive, a default synonym table is consulted (currently just contains a synonym for COLOUR), minimum-matching is turned on, 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'}); 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. 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. 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()). 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. 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. 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.