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yap-6.3/swi/library/prolog_source.pl

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/* $Id: prolog_source.pl,v 1.1 2008-02-12 17:03:53 vsc Exp $
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: wielemak@science.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2005, 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
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- module(prolog_source,
[ prolog_read_source_term/4, % +Stream, -Term, -Expanded, +Options
prolog_open_source/2, % +Source, -Stream
prolog_close_source/1, % +Stream
prolog_canonical_source/2 % +Spec, -Id
]).
:- use_module(operators).
:- use_module(debug).
/** <module> Examine Prolog source-files
2014-09-11 20:06:57 +01:00
@ingroup SWILibrary
The modile prolog_source.pl provides predicates to open, close and read
terms from Prolog source-files. This may seem easy, but there are a
couple of problems that must be taken care of.
* Source files may start with #!, supporting PrologScript
* Embeded operators declarations must be taken into account
* Style-check options must be taken into account
* Operators and style-check options may be implied by directives
* On behalf of the development environment we also wish to
parse PceEmacs buffers
This module concentrates these issues in a single library. Intended
users of the library are:
$ prolog_xref.pl : The Prolog cross-referencer
$ PceEmacs : Emacs syntax-colouring
$ PlDoc : The documentation framework
*/
:- thread_local
open_source/2. % Stream, State
:- multifile
requires_library/2,
prolog:xref_source_identifier/2, % +Source, -Id
prolog:xref_open_source/2. % +SourceId, -Stream
:- if(current_prolog_flag(dialect, yap)).
% yap
'$style_check'([Singleton,Discontiguous,Multiple], StyleF) :-
(
prolog_flag(single_var_warnings,on)
->
Singleton = singleton
;
Singleton = -singleton
),
(
prolog_flag(discontiguous_warnings,on)
->
Discontiguous = discontiguous
;
Discontiguous = -discontiguous
),
(
prolog_flag(redefine_warnings,on)
->
Multiple = multiple
;
Multiple = -multiple
),
style_check(StyleF).
:- endif.
/*******************************
* READING *
*******************************/
%% prolog_read_source_term(+In, -Term, -Expanded, +Options) is det.
%
% Read a term from a Prolog source-file. Options is a option list
% as normally provided to read_term/3.
%
% @param Term Term read
% @param Expanded Result of term-expansion on the term
prolog_read_source_term(In, Term, Expanded, Options) :-
'$set_source_module'(SM, SM),
read_term(In, Term,
[ module(SM)
| Options
]),
expand(Term, Expanded),
update_state(Expanded).
expand(Var, Var) :-
var(Var), !.
expand(Term, _) :-
requires_library(Term, Lib),
ensure_loaded(user:Lib),
fail.
expand('$:-'(X), '$:-'(X)) :- !, % boot module
style_check(+dollar).
expand(Term, Expanded) :-
expand_term(Term, Expanded).
%% requires_library(+Term, -Library)
%
% known expansion hooks. May be expanded as multifile predicate.
requires_library((:- emacs_begin_mode(_,_,_,_,_)), library(emacs_extend)).
requires_library((:- draw_begin_shape(_,_,_,_)), library(pcedraw)).
%% update_state(+Expanded) is det.
%
% Update operators and style-check options from the expanded term.
update_state([]) :- !.
update_state([H|T]) :- !,
update_state(H),
update_state(T).
update_state((:- Directive)) :- !,
update_directive(Directive).
update_state((?- Directive)) :- !,
update_directive(Directive).
update_state(_).
update_directive(module(Module, Public)) :- !,
'$set_source_module'(_, Module),
public_operators(Public).
update_directive(op(P,T,N)) :- !,
'$set_source_module'(SM, SM),
push_op(P,T,SM:N).
update_directive(style_check(Style)) :-
style_check(Style), !.
update_directive(_).
public_operators([]).
public_operators([H|T]) :- !,
( H = op(_,_,_)
-> update_directive(H)
; true
),
public_operators(T).
/*******************************
* SOURCES *
*******************************/
%% prolog_open_source(+CanonicalId:atomic, -Stream:stream) is det.
%
% Open source with given canonical id (see
% prolog_canonical_source/2) and remove the #! line if any.
% Streams opened using this predicate must be closed using
% prolog_close_source/1. Typically using the skeleton below. Using
% this skeleton, operator and style-check options are
% automatically restored to the values before opening the source.
%
% ==
% process_source(Src) :-
% prolog_open_source(Src, In),
% call_cleanup(process(Src), prolog_close_source(In)).
% ==
prolog_open_source(Src, Fd) :-
( prolog:xref_open_source(Src, Fd)
-> true
; open(Src, read, Fd)
),
( peek_char(Fd, #) % Deal with #! script
-> skip(Fd, 10)
; true
),
push_operators([]),
'$set_source_module'(SM, SM),
'$style_check'(Style, Style),
asserta(open_source(Fd, state(Style, SM))).
%% prolog_close_source(+In:stream) is det.
%
% Close a stream opened using prolog_open_source/2. Restores
% operator and style options.
prolog_close_source(In) :-
pop_operators,
( retract(open_source(In, state(Style, SM)))
-> '$style_check'(_, Style),
'$set_source_module'(_, SM)
; assertion(fail)
),
close(In).
%% prolog_canonical_source(+SourceSpec:ground, -Id:atomic) is det.
%
% Given a user-specification of a source, generate a unique and
% indexable identifier for it. For files we use the
% prolog_canonical absolute filename.
prolog_canonical_source(Src, Id) :- % Call hook
prolog:xref_source_identifier(Src, Id), !.
prolog_canonical_source(User, user) :-
User == user, !.
prolog_canonical_source(Source, Src) :-
absolute_file_name(Source,
[ file_type(prolog),
access(read),
file_errors(fail)
],
Src), !.
prolog_canonical_source(Source, Src) :-
var(Source), !,
Src = Source.