update to more recent version of option.pl
This commit is contained in:
Vitor Santos Costa
parent
86af6ff3f6
commit
ca94b17049
160
LGPL/option.pl
160
LGPL/option.pl
@ -1,11 +1,11 @@
|
||||
/* $Id: option.pl,v 1.1 2008-02-12 17:03:53 vsc Exp $
|
||||
/* $Id$
|
||||
|
||||
Part of SWI-Prolog
|
||||
|
||||
Author: Jan Wielemaker
|
||||
E-mail: jan@swi.psy.uva.nl
|
||||
E-mail: J.Wielemaker@uva.nl
|
||||
WWW: http://www.swi-prolog.org
|
||||
Copyright (C): 1985-2002, University of Amsterdam
|
||||
Copyright (C): 1985-2009, University of Amsterdam
|
||||
|
||||
This program is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU General Public License
|
||||
@ -33,21 +33,62 @@
|
||||
[ option/2, % +Term, +List
|
||||
option/3, % +Term, +List, +Default
|
||||
select_option/3, % +Term, +Options, -RestOpts
|
||||
select_option/4 % +Term, +Options, -RestOpts, +Default
|
||||
select_option/4, % +Term, +Options, -RestOpts, +Default
|
||||
merge_options/3, % +New, +Old, -Merged
|
||||
meta_options/3 % :IsMeta, :OptionsIn, -OptionsOut
|
||||
]).
|
||||
:- use_module(library(lists)).
|
||||
|
||||
/** <module> Option list processing
|
||||
|
||||
The library(option) provides some utilities for processing option lists.
|
||||
Option lists are commonly used as an alternative for many arguments.
|
||||
Examples built-in predicates are open/4 and write_term/3. Naming the
|
||||
arguments results in more readable code and the list nature makes it
|
||||
easy to extend the list of options accepted by a predicate. Option lists
|
||||
come in two styles, both of which are handled by this library.
|
||||
|
||||
$ Name(Value) :
|
||||
This is the preferred style.
|
||||
|
||||
$ Name = Value :
|
||||
This is often used, but deprecated.
|
||||
|
||||
Processing options inside time critical code (loops) can cause serious
|
||||
overhead. One possibility is to define a record using library(record)
|
||||
and initialise this using make_<record>/2. In addition to providing good
|
||||
performance, this also provides type-checking and central declaration of
|
||||
defaults.
|
||||
|
||||
==
|
||||
:- record atts(width:integer=100, shape:oneof([box,circle])=box).
|
||||
|
||||
process(Data, Options) :-
|
||||
make_atts(Options, Attributes),
|
||||
action(Data, Attributes).
|
||||
|
||||
action(Data, Attributes) :-
|
||||
atts_shape(Attributes, Shape),
|
||||
...
|
||||
==
|
||||
|
||||
@tbd We should consider putting many options in an assoc or record
|
||||
with appropriate preprocessing to achieve better performance.
|
||||
@tbd We should provide some standard to to automatic type-checking
|
||||
on option lists.
|
||||
@see library(record)
|
||||
*/
|
||||
|
||||
%% option(?Option, +OptionList, +Default)
|
||||
%
|
||||
% Get an option from a OptionList. OptionList can use the
|
||||
% Name=Value as well as the Name(Value) convention.
|
||||
%
|
||||
%
|
||||
% @param Option Term of the form Name(?Value).
|
||||
|
||||
option(Opt, Options, Default) :- % make option processing stead-fast
|
||||
arg(1, Opt, OptVal),
|
||||
nonvar(OptVal), !,
|
||||
ground(OptVal), !,
|
||||
functor(Opt, OptName, 1),
|
||||
functor(Gen, OptName, 1),
|
||||
option(Gen, Options, Default),
|
||||
@ -62,7 +103,7 @@ option(Opt, _, Default) :-
|
||||
% Get an option from a OptionList. OptionList can use the
|
||||
% Name=Value as well as the Name(Value) convention. Fails silently
|
||||
% if the option does not appear in OptionList.
|
||||
%
|
||||
%
|
||||
% @param Option Term of the form Name(?Value).
|
||||
|
||||
option(Opt, Options) :- % make option processing stead-fast
|
||||
@ -86,8 +127,9 @@ get_option(Opt, Options) :-
|
||||
|
||||
%% select_option(?Option, +Options, -RestOptions) is semidet.
|
||||
%
|
||||
% As option/2, removing the matching option from Options and
|
||||
% unifying the remaining options with RestOptions.
|
||||
% Get and remove option from an option list. As option/2, removing
|
||||
% the matching option from Options and unifying the remaining
|
||||
% options with RestOptions.
|
||||
|
||||
select_option(Opt, Options0, Options) :- % stead-fast
|
||||
arg(1, Opt, OptVal),
|
||||
@ -109,10 +151,106 @@ get_option(Opt, Options0, Options) :-
|
||||
|
||||
%% select_option(?Option, +Options, -RestOptions, +Default) is det.
|
||||
%
|
||||
% As select_option/3, but if Option is not in Options, its value
|
||||
% is unified with Default and RestOptions with Options.
|
||||
% Get and remove option with default value. As select_option/3,
|
||||
% but if Option is not in Options, its value is unified with
|
||||
% Default and RestOptions with Options.
|
||||
|
||||
select_option(Option, Options, RestOptions, _Default) :-
|
||||
select_option(Option, Options, RestOptions), !.
|
||||
select_option(Option, Options, Options, Default) :-
|
||||
arg(1, Option, Default).
|
||||
|
||||
|
||||
%% merge_options(+New, +Old, -Merged) is det.
|
||||
%
|
||||
% Merge two option lists. Merged is a sorted list of options using
|
||||
% the canonical format Name(Value) holding all options from New
|
||||
% and Old, after removing conflicting options from Old.
|
||||
|
||||
merge_options([], Old, Merged) :- !, Merged = Old.
|
||||
merge_options(New, [], Merged) :- !, Merged = New.
|
||||
merge_options(New, Old, Merged) :-
|
||||
canonise_options(New, NCanonical),
|
||||
canonise_options(Old, OCanonical),
|
||||
sort(NCanonical, NSorted),
|
||||
sort(OCanonical, OSorted),
|
||||
ord_merge(NSorted, OSorted, Merged).
|
||||
|
||||
ord_merge([], L, L) :- !.
|
||||
ord_merge(L, [], L) :- !.
|
||||
ord_merge([NO|TN], [OO|TO], Merged) :-
|
||||
functor(NO, NName, 1),
|
||||
functor(OO, OName, 1),
|
||||
compare(Diff, NName, OName),
|
||||
ord_merge(Diff, NO, NName, OO, OName, TN, TO, Merged).
|
||||
|
||||
ord_merge(=, NO, _, _, _, TN, TO, [NO|T]) :-
|
||||
ord_merge(TN, TO, T).
|
||||
ord_merge(<, NO, _, OO, OName, TN, TO, [NO|T]) :-
|
||||
( TN = [H|TN2]
|
||||
-> functor(H, NName, 1),
|
||||
compare(Diff, NName, OName),
|
||||
ord_merge(Diff, H, NName, OO, OName, TN2, TO, T)
|
||||
; T = [OO|TO]
|
||||
).
|
||||
ord_merge(>, NO, NName, OO, _, TN, TO, [OO|T]) :-
|
||||
( TO = [H|TO2]
|
||||
-> functor(H, OName, 1),
|
||||
compare(Diff, NName, OName),
|
||||
ord_merge(Diff, NO, NName, H, OName, TN, TO2, T)
|
||||
; T = [NO|TN]
|
||||
).
|
||||
|
||||
|
||||
%% canonise_options(+OptionsIn, -OptionsOut) is det.
|
||||
%
|
||||
% Rewrite option list from possible Name=Value to Name(Value)
|
||||
|
||||
canonise_options(In, Out) :-
|
||||
memberchk(_=_, In), !, % speedup a bit if already ok.
|
||||
canonise_options2(In, Out).
|
||||
canonise_options(Options, Options).
|
||||
|
||||
canonise_options2([], []).
|
||||
canonise_options2([Name=Value|T0], [H|T]) :- !,
|
||||
H =.. [Name,Value],
|
||||
canonise_options2(T0, T).
|
||||
canonise_options2([H|T0], [H|T]) :- !,
|
||||
canonise_options2(T0, T).
|
||||
|
||||
|
||||
%% meta_options(+IsMeta, :Options0, -Options) is det.
|
||||
%
|
||||
% Perform meta-expansion on options that are module-sensitive.
|
||||
% Whether an option name is module sensitive is determined by
|
||||
% calling call(IsMeta, Name). Here is an example:
|
||||
%
|
||||
% ==
|
||||
% meta_options(is_meta, OptionsIn, Options),
|
||||
% ...
|
||||
%
|
||||
% is_meta(callback).
|
||||
% ==
|
||||
|
||||
:- meta_predicate
|
||||
meta_options(1, :, -).
|
||||
|
||||
meta_options(IsMeta, Context:Options0, Options) :-
|
||||
meta_options(Options0, IsMeta, Context, Options).
|
||||
|
||||
meta_options([], _, _, []).
|
||||
meta_options([H0|T0], IM, Context, [H|T]) :-
|
||||
meta_option(H0, IM, Context, H),
|
||||
meta_options(T0, IM, Context, T).
|
||||
|
||||
meta_option(Name=V0, IM, Context, Name=M:V) :-
|
||||
call(IM, Name), !,
|
||||
strip_module(Context:V0, M, V).
|
||||
meta_option(O0, IM, Context, O) :-
|
||||
compound(O0),
|
||||
O0 =.. [Name,V0],
|
||||
call(IM, Name), !,
|
||||
strip_module(Context:V0, M, V),
|
||||
O =.. [Name,M:V].
|
||||
meta_option(O, _, _, O).
|
||||
|
||||
|
||||
Reference in New Issue
Block a user