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semweb and http compile now (but they don't work properly yet).

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This commit is contained in:
Vitor Santos Costa
2010-07-15 23:35:37 +01:00
parent 12fe06aa2e
commit 6183ff0282
158 changed files with 82184 additions and 1 deletions
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packages/semweb/rdf_turtle.pl Normal file
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/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@cs.vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2004-2009, 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
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 Lesser 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(rdf_turtle,
[ rdf_load_turtle/3, % +Input, -Triples, +Options
rdf_read_turtle/3, % +Input, -Triples, +Options
rdf_process_turtle/3 % +Input, :OnObject, +Options
]).
:- use_module(library(assoc)).
:- use_module(library(option)).
:- use_module(library('semweb/rdf_db')).
:- use_module(library(debug)).
:- use_module(library(uri)).
:- use_module(library(record)).
:- use_module(library(http/http_open)).
:- use_module(turtle_base).
:- meta_predicate
rdf_process_turtle(+,2,+).
/** <module> Turtle: Terse RDF Triple Language
This module implements the Turtle language for representing the RDF
triple model as defined by Dave Beckett from the Institute for Learning
and Research Technology University of Bristol in the document:
* http://www.w3.org/TeamSubmission/turtle/
* http://www.w3.org/TeamSubmission/2008/SUBM-turtle-20080114/#sec-conformance
This parser passes all tests, except for test-28.ttl (decial number
serialization) and test-29.ttl (uri containing ...%&...). It is unclear
to me whether these tests are correct. Notably, it is unclear whether we
must do %-decoding. Certainly, this is expected by various real-life
datasets that we came accross with.
This module acts as a plugin to rdf_load/2, for processing files with
one of the extensions =|.ttl|=, =|.n3|= or =|.nt|=.
@tbd Better error handling
*/
:- record ttl_state(base_uri,
resources:oneof([uri,iri])=uri,
prefix_map,
nodeid_map,
anon_prefix,
anon_count=0,
graph,
input,
line_no=0,
on_error:oneof([warning,error])=warning,
error_count=0).
%% rdf_read_turtle(+Input, -Triples, +Options)
%
% Read a stream or file into a set of triples of the format
%
% rdf(Subject, Predicate, Object)
%
% The representation is consistent with the SWI-Prolog RDF/XML
% and ntriples parsers. Provided options are:
%
% * base_uri(+BaseURI)
% Initial base URI. Defaults to file://<file> for loading
% files.
%
% * anon_prefix(+Prefix)
% Blank nodes are generated as <Prefix>1, <Prefix>2, etc.
% If Prefix is not an atom blank nodes are generated as
% node(1), node(2), ...
%
% * resources(URIorIRI)
% Officially, Turtle resources are IRIs. Quite a
% few applications however send URIs. By default we
% do URI->IRI mapping because this rarely causes errors.
% To force strictly conforming mode, pass =iri=.
%
% * prefixes(-Pairs)
% Return encountered prefix declarations as a
% list of Alias-URI
%
% * namespaces(-Pairs)
% Same as prefixes(Pairs). Compatibility to rdf_load/2.
%
% * base_used(-Base)
% Base URI used for processing the data. Unified to
% [] if there is no base-uri.
%
% * on_error(+ErrorMode)
% In =warning= (default), print the error and continue
% parsing the remainder of the file. If =error=, abort
% with an exception on the first error encountered.
%
% * error_count(-Count)
% If on_error(warning) is active, this option cane be
% used to retrieve the number of generated errors.
rdf_read_turtle(In, Triples, Options) :-
open_input(In, Stream, Close),
init_state(In, Stream, Options, State),
call_cleanup(phrase(turtle_file(State, Stream), Triples),
Close),
post_options(State, Options).
%% rdf_load_turtle(+Input, -Triples, +Options)
%
% @deprecated Use rdf_read_turtle/3
rdf_load_turtle(Input, Triples, Options) :-
rdf_read_turtle(Input, Triples, Options).
%% rdf_process_turtle(+Input, :OnObject, +Options) is det.
%
% Process Turtle input from Input, calling OnObject with a list of
% triples. Options is the same as for rdf_load_turtle/3.
%
% Errors encountered are sent to print_message/2, after which the
% parser tries to recover and parse the remainder of the data.
rdf_process_turtle(In, OnObject, Options) :-
open_input(In, Stream, Close),
init_state(In, Stream, Options, State),
call_cleanup(process_stream(State, Stream, OnObject),
Close),
post_options(State, Options).
post_options(State, Options) :-
prefix_option(State, Options),
namespace_option(State, Options),
base_option(State, Options),
error_option(State, Options).
prefix_option(State, Options) :-
( option(prefixes(Pairs), Options)
-> ttl_state_prefix_map(State, Map),
assoc_to_list(Map, Pairs)
; true
).
namespace_option(State, Options) :-
( option(namespaces(Pairs), Options)
-> ttl_state_prefix_map(State, Map),
assoc_to_list(Map, Pairs)
; true
).
base_option(State, Options) :-
( option(base_used(Base), Options)
-> ttl_state_base_uri(State, Base)
; true
).
error_option(State, Options) :-
( option(error_count(Count), Options)
-> ttl_state_error_count(State, Count)
; true
).
process_stream(State, In, OnObject) :-
read_turtle_tokens(In, Tokens, State),
debug(turtle, 'Tokens: ~w~n', [Tokens]),
ttl_state_line_no(State, LineNo),
( Tokens == end_of_file
-> true
; catch(phrase(triples(State, Triples), Tokens), E, true)
-> ( var(E)
-> ( Triples == []
-> true
; ttl_state_graph(State, DB),
call(OnObject, Triples, DB:LineNo)
)
; print_message(error, E)
),
process_stream(State, In, OnObject)
; syntax_error_term(In, LineNo, cannot_parse, Error),
step_error(State, Error),
process_stream(State, In, OnObject)
).
%% step_error(+State, +Error) is det.
%
% Throw Error of =on_error= is =error=. Otherwise print the error
% and increment =error_count=.
%
% @error syntax_error(Culprit).
step_error(State, Error) :-
ttl_state_on_error(State, error), !,
throw(Error).
step_error(State, Error) :-
ttl_state_error_count(State, E0),
succ(E0, E),
nb_set_error_count_of_ttl_state(E, State),
print_message(error, Error).
%% open_input(+Input, -Stream, -Close) is det.
%
% Open given input.
%
% @param Close goal to undo the open action
% @tbd Synchronize with input handling of rdf_db.pl.
% @error existence_error, permission_error
open_input(stream(Stream), Stream, true) :- !,
stream_property(Stream, encoding(Old)),
( Old == utf8
-> Close = true
; set_stream(Stream, encoding(utf8)),
Close = set_stream(Stream, encoding(Old))
).
open_input(Stream, Stream, Close) :-
is_stream(Stream), !,
open_input(stream(Stream), Stream, Close).
open_input(URL, Stream, close(Stream)) :-
sub_atom(URL, 0, _, _, 'http://'), !,
http_open(URL, Stream, []),
set_stream(Stream, encoding(utf8)).
open_input(File, Stream, close(Stream)) :-
absolute_file_name(File, Path,
[ access(read),
extensions([ttl, ''])
]),
open(Path, read, Stream, [encoding(utf8)]).
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
The parser is a two-stage processor. The first reads the raw file input
and generates a list of tokens, stripping comments and white space. It
is defined to read a single statement upto its terminating '.'. The
second stage is a traditional DCG parser generating the triples for the
statement.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
init_state(In, Stream, Options, State) :-
( option(base_uri(BaseURI), Options)
-> true
; In = stream(_)
-> BaseURI = []
; uri_is_global(In),
\+ is_absolute_file_name(In) % Avoid C:Path in Windows
-> uri_normalized(In, BaseURI)
; uri_file_name(BaseURI, In)
),
( option(anon_prefix(Prefix), Options)
-> true
; BaseURI == []
-> Prefix = '__bnode'
; atom_concat('__', BaseURI, Prefix)
),
option(db(DB), Options, BaseURI),
option(on_error(OnError), Options, warning),
option(resources(URIIRI), Options, uri),
empty_assoc(Map),
empty_assoc(NodeMap),
make_ttl_state([ base_uri(BaseURI),
resources(URIIRI),
prefix_map(Map),
nodeid_map(NodeMap),
anon_prefix(Prefix),
graph(DB),
input(Stream),
on_error(OnError)
], State).
turtle_file(State, In) -->
{ read_turtle_tokens(In, Tokens, State),
debug(turtle, 'Tokens: ~w~n', [Tokens])
},
( { Tokens == end_of_file }
-> []
; { catch(phrase(triples(State, Triples), Tokens), E, true) }
-> ( { var(E) }
-> list(Triples),
turtle_file(State, In)
; { step_error(State, E) },
turtle_file(State, In)
)
; { ttl_state_line_no(State, LineNo),
syntax_error_term(In, LineNo, cannot_parse, Error),
step_error(State, Error)
},
turtle_file(State, In)
).
list([]) --> [].
list([H|T]) --> [H], list(T).
triples(State, []) -->
[ '@', name(prefix), name(Prefix), : ], !,
iri(State, URI),
{ ttl_state_prefix_map(State, Map0),
put_assoc(Prefix, Map0, URI, Map),
set_prefix_map_of_ttl_state(Map, State)
}.
triples(State, []) -->
[ '@', name(prefix), ':' ], !,
iri(State, URI),
{ set_base_uri_of_ttl_state(URI, State)
}.
triples(State, []) -->
[ '@', name(base) ], !,
iri(State,URI),
{ set_base_uri_of_ttl_state(URI, State)
}.
triples(State, Triples) -->
subject(State, Subject, Triples, T),
( predicate_object_list(State, Subject, T, [])
-> ( eos
-> []
; syntax_rule(State, expected(predicate_object_list))
)
; { Triples \== T } % [ p o ; ... ] .
-> { T = [] }
).
eos([], []).
subject(State, Subject, T, T) -->
resource(State, Subject), !.
subject(State, Subject, T0, T) -->
blank(State, Subject, T0, T), !.
subject(State, _, _, _) -->
syntax_rule(State, subject_expected).
predicate_object_list(State, Subject, Triples, Tail) -->
verb(State, Predicate),
object_list(State, Subject, Predicate, Triples, Tail0),
( [';']
-> opt_predicate_object_list(State, Subject, Tail0, Tail)
; {Tail0 = Tail}
).
opt_predicate_object_list(State, Subject, Triples, Tail) -->
predicate_object_list(State, Subject, Triples, Tail), !.
opt_predicate_object_list(_, _, Tail, Tail) -->
[].
object_list(State, Subject, Predicate,
[rdf(Subject, Predicate, Object)|T0], T) -->
object(State, Object, T0, T1),
( [',']
-> object_list(State, Subject, Predicate, T1, T)
; {T1 = T}
).
verb(_, P) -->
[name(a)], !,
{ rdf_equal(rdf:type, P)
}.
verb(State, P) -->
resource(State, P).
object(State, Object, T, T) -->
[ literal(Value) ], !,
{ mk_object(Value, State, Object)
}.
object(_, literal(type(Type, N)), T, T) -->
[ numeric(Tp, Codes) ], !,
{ numeric_url(Tp, Type),
normalise_number(Tp, Codes, N)
}.
object(State, Object, T, T) -->
resource(State, Object), !.
object(State, Object, T0, T) -->
blank(State, Object, T0, T), !.
object(_, Object, T, T) -->
[ name(Bool) ],
{ boolean(Bool),
Object = literal(type(BoolType, Bool)),
rdf_equal(BoolType, xsd:boolean)
}.
object(State, _, _, _) -->
syntax_rule(State, expected_object).
%% normalise_number(+Type, +Codes:list, -Literal:atom) is det.
%
% Turtle normalisation of numbers. Currently only implemented for
% integers. This ensures that 0001 is parsed as "1"^^xsd:integer.
%
% Hmmm. Acording to test-10.ttl, this must *not* be done, so for
% now we disable all normalization.
%normalise_number(integer, Codes, N) :-
% number_codes(I, Codes),
% atom_number(N, I).
normalise_number(_, Codes, N) :-
atom_codes(N, Codes).
term_expansion(numeric_url(I, Local),
numeric_url(I, URI)) :-
rdf_global_id(Local, URI).
numeric_url(integer, xsd:integer).
numeric_url(decimal, xsd:decimal).
numeric_url(double, xsd:double).
boolean(true).
boolean(false).
resource(State, IRI) -->
iri(State, IRI), !.
resource(State, IRI) -->
[ :(Name) ], !,
{ ttl_state_base_uri(State, Base),
atom_concat(Base, Name, URI),
uri_iri(State, URI, IRI)
}.
resource(State, IRI) -->
[ name(Prefix), : ], !,
{ ttl_state_prefix_map(State, Map),
get_assoc(Prefix, Map, IRI)
}.
resource(State, IRI) -->
[ Prefix:Name ], !,
{ ttl_state_prefix_map(State, Map),
( get_assoc(Prefix, Map, Base)
-> atom_concat(Base, Name, URI),
uri_iri(State, URI, IRI)
; throw(error(existence_error(prefix, Prefix), _))
)
}.
resource(State, BaseIRI) -->
[ : ], !,
{ ttl_state_base_uri(State, BaseIRI)
}.
uri_iri(State, URI, IRI) :-
( ttl_state_resources(State, uri)
-> uri_iri(URI, IRI)
; IRI = URI
).
iri(State, IRI) -->
[ relative_uri(Rel)
],
{ ttl_state_base_uri(State, Base),
( Rel == '' % must be in global_url?
-> IRI = Base
; uri_normalized_iri(Rel, Base, IRI)
)
}.
blank(State, Resource, T, T) -->
[ nodeId(NodeId) ], !,
{ ttl_state_nodeid_map(State, IdMap),
( get_assoc(NodeId, IdMap, Resource)
-> true
; anonid(State, NodeId, Resource),
put_assoc(NodeId, IdMap, Resource, NewIdMap),
set_nodeid_map_of_ttl_state(NewIdMap, State)
)
}.
blank(State, Resource, T, T) -->
[ '[', ']' ], !,
{ anonid(State, Resource)
}.
blank(State, Resource, T0, T) -->
[ '[' ], !,
{ anonid(State, Resource)
},
predicate_object_list(State, Resource, T0, T),
[ ']' ].
blank(State, Resource, T0, T) -->
[ '(' ],
item_list(State, Resource, T0, T).
item_list(_State, Resource, T, T) -->
[ ')' ], !,
{ rdf_equal(rdf:nil, Resource)
}.
item_list(State, Resource, T0, T) -->
{ anonid(State, Resource) },
object(State, Object, T0, T1),
{ rdf_equal(rdf:first, First),
rdf_equal(rdf:rest, Rest),
T1 = [ rdf(Resource, First, Object),
rdf(Resource, Rest, Tail)
| T2
]
},
item_list(State, Tail, T2, T).
anonid(State, Node) :-
ttl_state_anon_prefix(State, AnonPrefix),
ttl_state_anon_count(State, C0),
Count is C0 + 1,
set_anon_count_of_ttl_state(Count, State),
( atom(AnonPrefix)
-> atom_concat(AnonPrefix, Count, Node)
; Node = node(Count)
).
anonid(State, _NodeId, Node) :-
ttl_state_anon_prefix(State, AnonPrefix),
atom(AnonPrefix), !,
anonid(State, Node).
anonid(_State, NodeId, node(NodeId)).
mk_object(type(Prefix:Name, Value), State, literal(type(Type, Value))) :- !,
ttl_state_prefix_map(State, Map),
get_assoc(Prefix, Map, Base),
atom_concat(Base, Name, Type).
mk_object(type(relative_uri(Rel), Value), State, literal(type(Type, Value))) :- !,
ttl_state_base_uri(State, Base),
( Rel == '' % must be in global_url?
-> Type = Base
; uri_normalized_iri(Rel, Base, Type)
).
mk_object(type(:(Name), Value), State, literal(type(Type, Value))) :- !,
ttl_state_base_uri(State, Base),
atom_concat(Base, Name, Type).
mk_object(Value, _State, literal(Value)).
syntax_rule(State, Error) -->
error_tokens(7, Tokens),
{ ttl_state_input(State, Stream),
stream_property(Stream, file_name(File)),
ttl_state_line_no(State, LineNo),
atomic_list_concat(Tokens, ' ', Before),
format(string(Msg), '~w:~d (before "~w ...")',
[File, LineNo, Before]),
throw(error(syntax_error(Error),
context(_, Msg)))
}.
%% error_tokens(+Count, -Tokens) is det.
%
% Return maximum Count tokens, converted back to turtle input
% syntax.
error_tokens(N, [H|T]) -->
{ succ(N2, N) },
error_token(H), !,
error_tokens(N2, T).
error_tokens(_, []) --> [].
error_token(Name) -->
[ name(Name) ], !.
error_token(Text) -->
[ numeric(_, Codes) ], !,
{ atom_codes(Text, Codes) }.
error_token(Text) -->
[ literal(Literal) ], !,
{ literal_text(Literal, Text) }.
error_token(Text) -->
[ URIToken ],
{ uri_text(URIToken, Text) }, !.
error_token(Punct) -->
[ Punct ],
{ atom(Punct) }, !.
error_token(Rest) -->
[ H ],
{ term_to_atom(H, Rest) }.
literal_text(type(Type, Value), Text) :- !,
uri_text(Type, TypeText),
format(atom(Text), '"~w"^^~w', [Value, TypeText]).
uri_text(relative_uri(URI), Text) :-
format(atom(Text), '<~w>', [URI]).
uri_text(:(Name), Text) :-
format(atom(Text), ':~w', [Name]).
/*******************************
* TOKENISER *
*******************************/
%% read_turtle_tokens(+In, -List, +State) is det.
%
% Read the next Turtle statement as a list of tokens. If
% on_error(warning) is active, failure prints a message and
% continues reading the next statements.
%
% The line_no property of the state is set to the start-line
%
% @error syntax_error(Culprit)
read_turtle_tokens(In, List, State) :-
ttl_state_on_error(State, error), !,
line_count(In, LineNo),
nb_set_line_no_of_ttl_state(LineNo, State),
( turtle_tokens(In, List)
-> true
; syntax_error_term(In, LineNo, illegal_token, Error),
throw(Error)
).
read_turtle_tokens(In, List, State) :-
line_count(In, LineNo),
nb_set_line_no_of_ttl_state(LineNo, State),
( catch(turtle_tokens(In, List), Error, true)
-> ( var(Error)
-> true
; print_message(error, Error),
skip_statement(In),
read_turtle_tokens(In, List, State)
)
; syntax_error_term(In, LineNo, illegal_token, Error),
print_message(error, Error),
skip_statement(In),
read_turtle_tokens(In, List, State)
).
%% skip_statement(+In)
%
% Skip to the end of the statement
skip_statement(In) :-
get_code(In, C0),
skip_statement(C0, In).
skip_statement(-1, _) :- !.
skip_statement(0'., In) :-
get_code(In, C),
( turtle_ws(C)
-> !
; skip_statement(C, In)
).
skip_statement(_, In) :-
get_code(In, C),
skip_statement(C, In).
%% turtle_tokens(+In, -List)
%
% Read a statement from a turtle file, returning the contents as a
% list of tokens.
turtle_tokens(In, List) :-
get_code(In, C0),
turtle_token(C0, In, C1, Tok1),
( Tok1 == end_of_file
-> List = end_of_file
; List = [Tok1|Tokens],
turtle_tokens(C1, In, Tokens)
).
turtle_tokens(C0, In, List) :-
( turtle_token(C0, In, C1, H)
-> debug(turtle(token), 'Token: ~q', [H])
; syntax_error(In, -1, illegal_token)
),
( H == '.'
-> List = []
; H == end_of_file
-> syntax_error(In, -1, unexpected_end_of_input)
; List = [H|T],
turtle_tokens(C1, In, T)
).
turtle_token(-1, _, -1, end_of_file) :- !.
turtle_token(0'., _, end, '.') :- !. % Turtle does not demand a space here!
turtle_token(0'#, In, C, Token) :- !,
get_code(In, C1),
skip_line(C1, In, C2),
turtle_token(C2, In, C, Token).
turtle_token(WS, In, C, Token) :-
turtle_ws(WS), !,
get_code(In, C1),
turtle_token(C1, In, C, Token).
turtle_token(C0, In, C, Number) :-
between(0'0, 0'9, C0), !,
turtle_number(C0, In, C, Number).
turtle_token(0'-, In, C, Number) :- !,
turtle_number(0'-, In, C, Number).
turtle_token(0'+, In, C, Number) :- !,
turtle_number(0'+, In, C, Number).
turtle_token(0'", In, C, Literal) :- !,
turtle_read_string(0'", In, C1, Atom),
( C1 == 0'@
-> get_code(In, C2),
language(C2, In, C, LangCodes),
atom_codes(LangId, LangCodes),
Literal = literal(lang(LangId, Atom))
; C1 == 0'^,
peek_code(In, 0'^)
-> get_code(In, 0'^),
get_code(In, C2),
resource_token(C2, In, C, Type),
Literal = literal(type(Type, Atom))
; C = C1,
Literal = literal(Atom)
).
turtle_token(0'_, In, C, nodeId(NodeID)) :-
peek_code(In, 0':), !,
get_code(In, _),
get_code(In, C1),
turtle_read_name(C1, In, C, NodeID).
turtle_token(0'<, In, C, URI) :- !,
resource_token(0'<, In, C, URI).
turtle_token(0':, In, C, URI) :- !,
resource_token(0':, In, C, URI).
turtle_token(C0, In, C, Token) :-
turtle_read_name(C0, In, C1, Name), !,
( C1 == 0':,
\+ sub_atom(Name, 0, _, _, '_'),
peek_code(In, C2),
turtle_name_start_char(C2)
-> get_code(In, C2),
turtle_read_name(C2, In, C, Name2),
Token = (Name:Name2)
; Token = name(Name),
C = C1
).
turtle_token(Punct, In, C, P) :-
punctuation(Punct, P), !,
get_code(In, C).
%% turtle_number(+Char0, +In, -CharNext, -Value)
%
% Value is Type:CodeList
turtle_number(0'-, In, CN, numeric(T, [0'-|Codes])) :- !,
get_code(In, C0),
turtle_number_nn(C0, In, CN, numeric(T, Codes)).
turtle_number(0'+, In, CN, numeric(T, [0'+|Codes])) :- !,
get_code(In, C0),
turtle_number_nn(C0, In, CN, numeric(T, Codes)).
turtle_number(C0, In, CN, Value) :-
turtle_number_nn(C0, In, CN, Value).
turtle_number_nn(C, In, CN, numeric(Type, Codes)) :-
turtle_integer_codes(C, In, CN0, Codes, T0), % [0-9]+
( CN0 == 0'.
-> T0 = [CN0|T1],
get_code(In, C1),
turtle_integer_codes(C1, In, CN1, T1, T2), % [0-9]+.[0-9]+
( exponent(CN1, In, CN, T2)
-> Type = double
; CN = CN1,
T2 = [],
Type = decimal
)
; exponent(CN0, In, CN, T0)
-> Type = double
; T0 = [],
CN = CN0,
Type = integer
).
turtle_integer_codes(C0, In, CN, [C0|T0], T) :-
between(0'0, 0'9, C0), !,
get_code(In, C1),
turtle_integer_codes(C1, In, CN, T0, T).
turtle_integer_codes(CN, _, CN, T, T).
exponent(C0, In, CN, [C0|T0]) :-
e(C0), !,
get_code(In, C1),
optional_sign(C1, In, CN0, T0, T1),
turtle_integer_codes(CN0, In, CN, T1, []).
optional_sign(C0, In, CN, [C0|T], T) :-
sign(C0), !,
get_code(In, CN).
optional_sign(CN, _, CN, T, T).
e(0'e).
e(0'E).
sign(0'-).
sign(0'+). %'
% language: [a-z]+ ('-' [a-z0-9]+ )*
language(C0, In, C, [C0|Codes]) :-
code_type(C0, lower),
get_code(In, C1),
lwr_word(C1, In, C2, Codes, Tail),
sub_langs(C2, In, C, Tail, []), !.
language(_, In, _, _) :-
line_count(In, LineNo),
syntax_error(In, LineNo, language_specifier).
lwr_word(C0, In, C, [C0|T0], T) :-
code_type(C0, lower), !,
get_code(In, C1),
lwr_word(C1, In, C, T0, T).
lwr_word(C, _, C, T, T).
sub_langs(0'-, In, C, [0'-, C1|Codes], T) :- !,
get_code(In, C1),
lwrdig(C1), !,
get_code(In, C2),
lwrdigs(C2, In, C3, Codes, Tail),
sub_langs(C3, In, C, Tail, T).
sub_langs(C, _, C, T, T).
lwrdig(C) :-
code_type(C, lower), !.
lwrdig(C) :-
code_type(C, digit).
lwrdigs(C0, In, C, [C0|T0], T) :-
lwrdig(C0), !,
get_code(In, C1),
lwr_word(C1, In, C, T0, T).
lwrdigs(C, _, C, T, T).
% resource_token
resource_token(0'<, In, C, relative_uri(URI)) :- !,
turtle_read_relative_uri(0'<, In, C, URI).
resource_token(0':, In, C, Token) :- !,
get_code(In, C0),
( turtle_read_name(C0, In, C, Name)
-> Token = :(Name)
; Token = :,
C = C0
).
resource_token(C0, In, C, Prefix:Name) :-
turtle_read_name(C0, In, C1, Prefix),
\+ sub_atom(Prefix, 0, _, _, '_'), !,
C1 == 0':,
get_code(In, C2),
turtle_read_name(C2, In, C, Name).
punctuation(0'(, '(').
punctuation(0'), ')').
punctuation(0'[, '[').
punctuation(0'], ']').
punctuation(0',, ',').
punctuation(0'@, '@').
punctuation(0':, ':').
punctuation(0';, ';').
% comment
skip_line(0xA, In, C) :- !,
get_code(In, C).
skip_line(0xD, In, C) :- !,
get_code(In, C).
skip_line(-1, _, -1) :- !.
skip_line(_, In, C) :-
get_code(In, C1),
skip_line(C1, In, C).
% ws
turtle_ws(0x9).
turtle_ws(0xA).
turtle_ws(0xD).
turtle_ws(0x20).
syntax_error(Stream, Line, Which) :-
syntax_error_term(Stream, Line, Which, Error),
throw(Error).
syntax_error_term(Stream, -1, Which, Error) :- !,
stream_property(Stream, file_name(File)),
line_count(Stream, LineNo),
line_position(Stream, LinePos),
character_count(Stream, CharIndex),
Error = error(syntax_error(Which),
file(File, LineNo, LinePos, CharIndex)).
syntax_error_term(Stream, LineNo, Which, Error) :-
stream_property(Stream, file_name(File)),
Error = error(syntax_error(Which),
file(File, LineNo, -1, -1)).
/*******************************
* RDF-DB HOOK *
*******************************/
:- multifile
rdf_db:rdf_load_stream/3,
rdf_db:rdf_file_type/2.
rdf_db:rdf_load_stream(turtle, Stream, _Module:Options) :-
rdf_db:graph(Options, Id),
rdf_transaction(rdf_process_turtle(Stream, assert_triples, Options),
parse(Id)).
assert_triples([], _).
assert_triples([rdf(S,P,O)|T], Location) :-
rdf_assert(S,P,O,Location),
assert_triples(T, Location).
rdf_db:rdf_file_type(ttl, turtle).
rdf_db:rdf_file_type(n3, turtle). % not really, but good enough
rdf_db:rdf_file_type(nt, turtle). % not really, but good enough