guile-rdf

tordf.scm

;;;; Copyright (C) 2020 Julien Lepiller <julien@lepiller.eu>
;;;; 
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 3 of the License, or (at your option) any later version.
;;;; 
;;;; This library 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
;;;; Lesser 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;;; 

(define-module (turtle tordf)
  #:use-module (ice-9 match)
  #:use-module (ice-9 textual-ports)
  #:use-module (iri iri)
  #:use-module (turtle parser)
  #:use-module (srfi srfi-9)
  #:use-module (rdf rdf)
  #:export (turtle->rdf))

(define-record-type parser-state
  (make-parser-state base-uri namespaces bnode-labels cur-subject cur-predicate
                     cur-object blank-node-gen result)
  parser-state?
  (base-uri       parser-state-base-uri)
  (namespaces     parser-state-namespaces)
  (bnode-labels   parser-state-bnode-labels)
  (cur-subject    parser-state-cur-subject)
  (cur-predicate  parser-state-cur-predicate)
  (cur-object     parser-state-cur-object)
  (blank-node-gen parser-state-blank-node-gen)
  (result         parser-state-result))

(define* (update-parser-state
           state #:key (base-uri (parser-state-base-uri state))
                       (namespaces (parser-state-namespaces state))
                       (bnode-labels (parser-state-bnode-labels state))
                       (cur-subject (parser-state-cur-subject state))
                       (cur-predicate (parser-state-cur-predicate state))
                       (cur-object (parser-state-cur-object state))
                       (blank-node-gen (parser-state-blank-node-gen state))
                       (result (parser-state-result state)))
  (make-parser-state base-uri namespaces bnode-labels cur-subject cur-predicate
                     cur-object blank-node-gen result))

(define (create-generate-blank-node)
  (define num 0)
  (lambda ()
    (set! num (+ num 1))
    num))

(define (add-ns-to-state state ns iri)
  (update-parser-state state
    #:namespaces (cons (cons ns iri) (parser-state-namespaces state))))

(define* (parse-string str #:optional for-iri?)
  (match str
    ((? string? str) str)
    ((component str ...)
     (match component
       ((? string? str1)
        (string-append str1 (parse-string str)))
       (('uchar n)
        (string-append (string (integer->char (string->number n 16)))
                       (parse-string str)))
       (('echar e)
        (string-append
          (match e
            ("\\t" "\t")
            ("\\b" "\b")
            ("\\n" "\n")
            ("\\r" "\r")
            ("\\f" "\f")
            ("\\\\" "\\")
            ("\\\"" "\"")
            ("\\'" "'"))
          (parse-string str)))))
    (() "")))

(define (valid-iri? iri)
  (and (not (string-any (ucs-range->char-set 0 33) iri))
       (not (string-any #\< iri))
       (not (string-any #\> iri))))

(define (parse-iri iri state)
  (match iri
    (('iri ('prefixed-name ('pname-ln ('pname-ns ns) ('pn-local suffix))))
     `(("iri" . ,(string-append (assoc-ref (parser-state-namespaces state) ns)
                                suffix))
       ("state" . ,state)))
    (('iri ('prefixed-name ('pname-ln ('pname-ns ('pn-local suffix)))))
     `(("iri" . ,(string-append (assoc-ref (parser-state-namespaces state) "")
                                suffix))
       ("state" . ,state)))
    (('iri ('prefixed-name ('pname-ns ns)))
     `(("iri" . ,(assoc-ref (parser-state-namespaces state) ns))
       ("state" . ,state)))
    (('iri ('prefixed-name 'pname-ns))
     `(("iri" . ,(assoc-ref (parser-state-namespaces state) ""))
       ("state" . ,state)))
    (('iri 'iriref)
     `(("iri" . ,(resolve-iri (parser-state-base-uri state) ""))
       ("state" . ,state)))
    (('iri ('iriref iri ...))
     (let ((iri (resolve-iri (parser-state-base-uri state) (parse-string iri))))
       (if (valid-iri? iri)
           `(("iri" . ,iri)
             ("state" . ,state))
           (throw 'invalid-iri iri))))))

(define (parse-verb verb state)
  (match verb
    ("a" `(("verb" . "http://www.w3.org/1999/02/22-rdf-syntax-ns#type")
           ("state" . ,state)))
    (('predicate iri)
     (let ((res (parse-iri iri state)))
       `(("verb" . ,(assoc-ref res "iri"))
         ("state" . ,(assoc-ref res "state")))))))

(define (parse-object object state)
  (match object
    (('rdf-literal ('string-pat (_ str ...)))
     (let ((object
             (make-rdf-literal (parse-string str)
                               "http://www.w3.org/2001/XMLSchema#string" #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('rdf-literal ('string-pat (_ str ...)) ("^^" iri))
     (let* ((res (parse-iri iri state))
            (iri (assoc-ref res "iri"))
            (state (assoc-ref res "state"))
            (object (make-rdf-literal (parse-string str) iri #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('rdf-literal ('string-pat (_ str ...)) ('langtag lang))
     (let ((object
           (make-rdf-literal
             (parse-string str)
             "http://www.w3.org/1999/02/22-rdf-syntax-ns#langString"
             lang)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('rdf-literal ('string-pat _) ("^^" iri))
     (let* ((res (parse-iri iri state))
            (iri (assoc-ref res "iri"))
            (state (assoc-ref res "state"))
            (object (make-rdf-literal "" iri #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('rdf-literal ('string-pat _) ('langtag lang))
     (let ((object
           (make-rdf-literal
             ""
             "http://www.w3.org/1999/02/22-rdf-syntax-ns#langString"
             lang)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('rdf-literal ('string-pat _))
     (let ((object
           (make-rdf-literal
             ""
             "http://www.w3.org/1999/02/22-rdf-syntax-ns#string"
             #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('numeric-literal ('decimal num))
     (let ((object
            (make-rdf-literal num "http://www.w3.org/2001/XMLSchema#decimal" #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('numeric-literal ('integer int))
     (let ((object
           (make-rdf-literal int "http://www.w3.org/2001/XMLSchema#integer" #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('numeric-literal ('double num))
     (let ((object
            (make-rdf-literal num "http://www.w3.org/2001/XMLSchema#double" #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('boolean-literal bool)
     (let ((object
             (make-rdf-literal bool "http://www.w3.org/2001/XMLSchema#boolean" #f)))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('blank-node ('anon _))
     (let ((node ((parser-state-blank-node-gen state))))
       (update-parser-state state
         #:cur-object node
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             node)
           (parser-state-result state)))))
    (('blank-node ('blank-node-label label))
     (let* ((node
              (or (assoc-ref (parser-state-bnode-labels state) label)
                  ((parser-state-blank-node-gen state))))
            (state
              (if (assoc-ref (parser-state-bnode-labels state) label)
                  state
                  (update-parser-state state
                    #:bnode-labels
                    (cons
                      (cons label node)
                      (parser-state-bnode-labels state))))))
       (update-parser-state state
         #:cur-object node
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             node)
           (parser-state-result state)))))
    (('blank-node-property-list ('predicate-object-list po ...))
     (let* ((node ((parser-state-blank-node-gen state)))
            (new-state (parse-predicate-object
                         po (update-parser-state state #:cur-subject node))))
       (update-parser-state new-state
         #:cur-object node
         #:cur-subject (parser-state-cur-subject state)
         #:cur-predicate (parser-state-cur-predicate state)
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             node)
           (parser-state-result new-state)))))
    ('collection
     (let ((object "http://www.w3.org/1999/02/22-rdf-syntax-ns#nil"))
       (update-parser-state state
         #:cur-object object
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             object)
           (parser-state-result state)))))
    (('collection objects ...)
     (let ((state (parse-collection objects state)))
       (update-parser-state state
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             (parser-state-cur-object state))
           (parser-state-result state)))))
    (('iri _)
     (let* ((res (parse-iri object state))
            (iri (assoc-ref res "iri"))
            (state (assoc-ref res "state")))
       (update-parser-state state
         #:cur-object iri
         #:result
         (cons
           (make-rdf-triple
             (parser-state-cur-subject state)
             (parser-state-cur-predicate state)
             iri)
           (parser-state-result state)))))))

(define (parse-collection collection state)
  (let ((node ((parser-state-blank-node-gen state))))
    (let loop ((objects collection)
               (new-state
                 (update-parser-state state
                   #:cur-subject node
                   #:cur-predicate
                   "http://www.w3.org/1999/02/22-rdf-syntax-ns#first"))
               (previous-object #nil))
      (match objects
        ('()
         (update-parser-state new-state
           #:cur-object node
           #:cur-subject (parser-state-cur-subject state)
           #:cur-predicate (parser-state-cur-predicate state)
           #:result
           (cons
             (make-rdf-triple
               previous-object
               "http://www.w3.org/1999/02/22-rdf-syntax-ns#rest"
               "http://www.w3.org/1999/02/22-rdf-syntax-ns#nil")
             (parser-state-result new-state))))
        ((('object object) objects ...)
         (if (equal? previous-object #nil)
             (let ((new-state (parse-object object new-state)))
               (loop objects new-state node))
             (let* ((node ((parser-state-blank-node-gen new-state)))
                    (new-state
                      (update-parser-state new-state
                        #:cur-subject node))
                    (new-state (parse-object object new-state)))
               (loop
                 objects
                 (update-parser-state new-state
                   #:result
                   (cons
                     (make-rdf-triple
                       previous-object
                       "http://www.w3.org/1999/02/22-rdf-syntax-ns#rest"
                       node)
                     (parser-state-result new-state)))
                 node))))))))

(define (parse-object-list ol state)
  (let loop ((ol ol) (state state))
    (match ol
      ('() state)
      ((('object object) ol ...)
       (loop ol (parse-object object state)))
      ((ol)
       (loop ol state)))))

(define (parse-predicate-object po state)
  (let loop ((po po) (state state))
    (match po
      ((('verb verb) ('object-list ol ...) po)
       (let* ((verb (parse-verb verb state))
              (state (assoc-ref verb "state"))
              (verb (assoc-ref verb "verb"))
              (new-state (update-parser-state state #:cur-predicate verb))
              (res (parse-object-list ol new-state)))
         (loop po res)))
      ((('verb verb) ('object-list ol ...))
       (let* ((verb (parse-verb verb state))
              (state (assoc-ref verb "state"))
              (verb (assoc-ref verb "verb"))
              (new-state (update-parser-state state #:cur-predicate verb))
              (res (parse-object-list ol new-state)))
         res))
      (((('verb verb) ('object-list ol ...)) po ...)
       (let* ((verb (parse-verb verb state))
              (state (assoc-ref verb "state"))
              (verb (assoc-ref verb "verb"))
              (new-state (update-parser-state state #:cur-predicate verb))
              (res (parse-object-list ol new-state)))
         (loop po res)))
      ('() state)
      ((po)
       (loop po state)))))

(define (parse-subject s state)
  (match s
    (('iri _ ...)
     (let ((res (parse-iri s state)))
       `(("subject" . ,(assoc-ref res "iri"))
         ("state" . ,(assoc-ref res "state")))))
    (('collection objects ...)
     (let ((res (parse-collection objects state)))
       `(("subject" . ,(parser-state-cur-object res))
         ("state" . ,res))))
    ('collection
     `(("subject" . "http://www.w3.org/1999/02/22-rdf-syntax-ns#nil")
       ("state" . ,state)))
    (('blank-node ('anon _))
     (let ((node ((parser-state-blank-node-gen state))))
       `(("subject" . ,node)
         ("state" . ,state))))
    (('blank-node ('blank-node-label label))
     (if (assoc-ref (parser-state-bnode-labels state) label)
         `(("subject" . ,(assoc-ref (parser-state-bnode-labels state) label))
           ("state" . ,state))
         (let ((node ((parser-state-blank-node-gen state))))
           `(("subject" . ,node)
             ("state" . ,(update-parser-state state
                           #:bnode-labels
                           (cons
                             (cons label node)
                             (parser-state-bnode-labels state))))))))))

(define (parse-triples t state)
  (match t
    ((('subject subject) ('predicate-object-list predicate-object ...))
     (let* ((res (parse-subject subject state))
            (subject (assoc-ref res "subject"))
            (state (assoc-ref res "state"))
            (state (update-parser-state state
                    #:cur-subject subject)))
       (parse-predicate-object predicate-object state)))
    ((('blank-node-property-list ('predicate-object-list po ...))
      ('predicate-object-list predicate-object ...))
     (let* ((subject ((parser-state-blank-node-gen state)))
            (new-state (parse-predicate-object
                         po (update-parser-state state #:cur-subject subject))))
       (parse-predicate-object predicate-object new-state)))
    ((('blank-node-property-list ('predicate-object-list po ...)))
     (let* ((subject ((parser-state-blank-node-gen state))))
       (parse-predicate-object po (update-parser-state state
                                    #:cur-subject subject))))))

(define (parse-turtle-doc parse-tree state)
  (let loop ((parse-tree parse-tree) (state state))
    (match parse-tree
      ('() (parser-state-result state))
      ((('prefix-id ('pname-ns ns) ('iriref iri ...)) parse-tree ...)
       (loop parse-tree
             (add-ns-to-state
               state ns (resolve-iri (parser-state-base-uri state)
                                     (parse-string iri)))))
      ((('prefix-id ('pname-ns ('iriref iri ...))) parse-tree ...)
       (loop parse-tree
             (add-ns-to-state
               state "" (resolve-iri (parser-state-base-uri state)
                                     (parse-string iri)))))
      ((('sparql-prefix ('pname-ns ns) ('iriref iri ...)) parse-tree ...)
       (loop parse-tree
             (add-ns-to-state
               state ns (resolve-iri (parser-state-base-uri state)
                                     (parse-string iri)))))
      ((('sparql-prefix ('pname-ns ('iriref iri ...))) parse-tree ...)
       (loop parse-tree
             (add-ns-to-state
               state "" (resolve-iri (parser-state-base-uri state)
                                     (parse-string iri)))))
      ((('base ('iriref iri ...)) parse-tree ...)
       (loop parse-tree
             (update-parser-state
               state #:base-uri (resolve-iri (parser-state-base-uri state)
                                             (parse-string iri)))))
      ((('sparql-base ('iriref iri ...)) parse-tree ...)
       (loop parse-tree
             (update-parser-state
               state #:base-uri (resolve-iri (parser-state-base-uri state)
                                             (parse-string iri)))))
      ((('triples t ...) parse-tree ...)
       (let ((res (parse-triples t state)))
         (loop parse-tree (parse-triples t state))))
      ;; otherwise, it's a single element, not a list of statements
      (((? symbol? _) _ ...) (loop (list parse-tree) state)))))

(define (tordf parse-tree base)
  (define state
    (make-parser-state base '() '() #f #f #f (create-generate-blank-node) '()))
  (parse-turtle-doc parse-tree state))

(define (turtle->rdf str-or-file base)
  (define str
    (cond ((port? str-or-file) (get-string-all str-or-file))
          ((string? str-or-file) str-or-file)))
  (let ((parse-tree (parse-turtle str)))
    (tordf parse-tree base)))


1	;;;; Copyright (C) 2020 Julien Lepiller <julien@lepiller.eu>
2	;;;;
3	;;;; This library is free software; you can redistribute it and/or
4	;;;; modify it under the terms of the GNU Lesser General Public
5	;;;; License as published by the Free Software Foundation; either
6	;;;; version 3 of the License, or (at your option) any later version.
7	;;;;
8	;;;; This library is distributed in the hope that it will be useful,
9	;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
10	;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11	;;;; Lesser General Public License for more details.
12	;;;;
13	;;;; You should have received a copy of the GNU Lesser General Public
14	;;;; License along with this library; if not, write to the Free Software
15	;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16	;;;;
17
18	(define-module (turtle tordf)
19	#:use-module (ice-9 match)
20	#:use-module (ice-9 textual-ports)
21	#:use-module (iri iri)
22	#:use-module (turtle parser)
23	#:use-module (srfi srfi-9)
24	#:use-module (rdf rdf)
25	#:export (turtle->rdf))
26
27	(define-record-type parser-state
28	(make-parser-state base-uri namespaces bnode-labels cur-subject cur-predicate
29	cur-object blank-node-gen result)
30	parser-state?
31	(base-uri parser-state-base-uri)
32	(namespaces parser-state-namespaces)
33	(bnode-labels parser-state-bnode-labels)
34	(cur-subject parser-state-cur-subject)
35	(cur-predicate parser-state-cur-predicate)
36	(cur-object parser-state-cur-object)
37	(blank-node-gen parser-state-blank-node-gen)
38	(result parser-state-result))
39
40	(define* (update-parser-state
41	state #:key (base-uri (parser-state-base-uri state))
42	(namespaces (parser-state-namespaces state))
43	(bnode-labels (parser-state-bnode-labels state))
44	(cur-subject (parser-state-cur-subject state))
45	(cur-predicate (parser-state-cur-predicate state))
46	(cur-object (parser-state-cur-object state))
47	(blank-node-gen (parser-state-blank-node-gen state))
48	(result (parser-state-result state)))
49	(make-parser-state base-uri namespaces bnode-labels cur-subject cur-predicate
50	cur-object blank-node-gen result))
51
52	(define (create-generate-blank-node)
53	(define num 0)
54	(lambda ()
55	(set! num (+ num 1))
56	num))
57
58	(define (add-ns-to-state state ns iri)
59	(update-parser-state state
60	#:namespaces (cons (cons ns iri) (parser-state-namespaces state))))
61
62	(define* (parse-string str #:optional for-iri?)
63	(match str
64	((? string? str) str)
65	((component str ...)
66	(match component
67	((? string? str1)
68	(string-append str1 (parse-string str)))
69	(('uchar n)
70	(string-append (string (integer->char (string->number n 16)))
71	(parse-string str)))
72	(('echar e)
73	(string-append
74	(match e
75	("\\t" "\t")
76	("\\b" "\b")
77	("\\n" "\n")
78	("\\r" "\r")
79	("\\f" "\f")
80	("\\\\" "\\")
81	("\\\"" "\"")
82	("\\'" "'"))
83	(parse-string str)))))
84	(() "")))
85
86	(define (valid-iri? iri)
87	(and (not (string-any (ucs-range->char-set 0 33) iri))
88	(not (string-any #\< iri))
89	(not (string-any #\> iri))))
90
91	(define (parse-iri iri state)
92	(match iri
93	(('iri ('prefixed-name ('pname-ln ('pname-ns ns) ('pn-local suffix))))
94	`(("iri" . ,(string-append (assoc-ref (parser-state-namespaces state) ns)
95	suffix))
96	("state" . ,state)))
97	(('iri ('prefixed-name ('pname-ln ('pname-ns ('pn-local suffix)))))
98	`(("iri" . ,(string-append (assoc-ref (parser-state-namespaces state) "")
99	suffix))
100	("state" . ,state)))
101	(('iri ('prefixed-name ('pname-ns ns)))
102	`(("iri" . ,(assoc-ref (parser-state-namespaces state) ns))
103	("state" . ,state)))
104	(('iri ('prefixed-name 'pname-ns))
105	`(("iri" . ,(assoc-ref (parser-state-namespaces state) ""))
106	("state" . ,state)))
107	(('iri 'iriref)
108	`(("iri" . ,(resolve-iri (parser-state-base-uri state) ""))
109	("state" . ,state)))
110	(('iri ('iriref iri ...))
111	(let ((iri (resolve-iri (parser-state-base-uri state) (parse-string iri))))
112	(if (valid-iri? iri)
113	`(("iri" . ,iri)
114	("state" . ,state))
115	(throw 'invalid-iri iri))))))
116
117	(define (parse-verb verb state)
118	(match verb
119	("a" `(("verb" . "http://www.w3.org/1999/02/22-rdf-syntax-ns#type")
120	("state" . ,state)))
121	(('predicate iri)
122	(let ((res (parse-iri iri state)))
123	`(("verb" . ,(assoc-ref res "iri"))
124	("state" . ,(assoc-ref res "state")))))))
125
126	(define (parse-object object state)
127	(match object
128	(('rdf-literal ('string-pat (_ str ...)))
129	(let ((object
130	(make-rdf-literal (parse-string str)
131	"http://www.w3.org/2001/XMLSchema#string" #f)))
132	(update-parser-state state
133	#:cur-object object
134	#:result
135	(cons
136	(make-rdf-triple
137	(parser-state-cur-subject state)
138	(parser-state-cur-predicate state)
139	object)
140	(parser-state-result state)))))
141	(('rdf-literal ('string-pat (_ str ...)) ("^^" iri))
142	(let* ((res (parse-iri iri state))
143	(iri (assoc-ref res "iri"))
144	(state (assoc-ref res "state"))
145	(object (make-rdf-literal (parse-string str) iri #f)))
146	(update-parser-state state
147	#:cur-object object
148	#:result
149	(cons
150	(make-rdf-triple
151	(parser-state-cur-subject state)
152	(parser-state-cur-predicate state)
153	object)
154	(parser-state-result state)))))
155	(('rdf-literal ('string-pat (_ str ...)) ('langtag lang))
156	(let ((object
157	(make-rdf-literal
158	(parse-string str)
159	"http://www.w3.org/1999/02/22-rdf-syntax-ns#langString"
160	lang)))
161	(update-parser-state state
162	#:cur-object object
163	#:result
164	(cons
165	(make-rdf-triple
166	(parser-state-cur-subject state)
167	(parser-state-cur-predicate state)
168	object)
169	(parser-state-result state)))))
170	(('rdf-literal ('string-pat _) ("^^" iri))
171	(let* ((res (parse-iri iri state))
172	(iri (assoc-ref res "iri"))
173	(state (assoc-ref res "state"))
174	(object (make-rdf-literal "" iri #f)))
175	(update-parser-state state
176	#:cur-object object
177	#:result
178	(cons
179	(make-rdf-triple
180	(parser-state-cur-subject state)
181	(parser-state-cur-predicate state)
182	object)
183	(parser-state-result state)))))
184	(('rdf-literal ('string-pat _) ('langtag lang))
185	(let ((object
186	(make-rdf-literal
187	""
188	"http://www.w3.org/1999/02/22-rdf-syntax-ns#langString"
189	lang)))
190	(update-parser-state state
191	#:cur-object object
192	#:result
193	(cons
194	(make-rdf-triple
195	(parser-state-cur-subject state)
196	(parser-state-cur-predicate state)
197	object)
198	(parser-state-result state)))))
199	(('rdf-literal ('string-pat _))
200	(let ((object
201	(make-rdf-literal
202	""
203	"http://www.w3.org/1999/02/22-rdf-syntax-ns#string"
204	#f)))
205	(update-parser-state state
206	#:cur-object object
207	#:result
208	(cons
209	(make-rdf-triple
210	(parser-state-cur-subject state)
211	(parser-state-cur-predicate state)
212	object)
213	(parser-state-result state)))))
214	(('numeric-literal ('decimal num))
215	(let ((object
216	(make-rdf-literal num "http://www.w3.org/2001/XMLSchema#decimal" #f)))
217	(update-parser-state state
218	#:cur-object object
219	#:result
220	(cons
221	(make-rdf-triple
222	(parser-state-cur-subject state)
223	(parser-state-cur-predicate state)
224	object)
225	(parser-state-result state)))))
226	(('numeric-literal ('integer int))
227	(let ((object
228	(make-rdf-literal int "http://www.w3.org/2001/XMLSchema#integer" #f)))
229	(update-parser-state state
230	#:cur-object object
231	#:result
232	(cons
233	(make-rdf-triple
234	(parser-state-cur-subject state)
235	(parser-state-cur-predicate state)
236	object)
237	(parser-state-result state)))))
238	(('numeric-literal ('double num))
239	(let ((object
240	(make-rdf-literal num "http://www.w3.org/2001/XMLSchema#double" #f)))
241	(update-parser-state state
242	#:cur-object object
243	#:result
244	(cons
245	(make-rdf-triple
246	(parser-state-cur-subject state)
247	(parser-state-cur-predicate state)
248	object)
249	(parser-state-result state)))))
250	(('boolean-literal bool)
251	(let ((object
252	(make-rdf-literal bool "http://www.w3.org/2001/XMLSchema#boolean" #f)))
253	(update-parser-state state
254	#:cur-object object
255	#:result
256	(cons
257	(make-rdf-triple
258	(parser-state-cur-subject state)
259	(parser-state-cur-predicate state)
260	object)
261	(parser-state-result state)))))
262	(('blank-node ('anon _))
263	(let ((node ((parser-state-blank-node-gen state))))
264	(update-parser-state state
265	#:cur-object node
266	#:result
267	(cons
268	(make-rdf-triple
269	(parser-state-cur-subject state)
270	(parser-state-cur-predicate state)
271	node)
272	(parser-state-result state)))))
273	(('blank-node ('blank-node-label label))
274	(let* ((node
275	(or (assoc-ref (parser-state-bnode-labels state) label)
276	((parser-state-blank-node-gen state))))
277	(state
278	(if (assoc-ref (parser-state-bnode-labels state) label)
279	state
280	(update-parser-state state
281	#:bnode-labels
282	(cons
283	(cons label node)
284	(parser-state-bnode-labels state))))))
285	(update-parser-state state
286	#:cur-object node
287	#:result
288	(cons
289	(make-rdf-triple
290	(parser-state-cur-subject state)
291	(parser-state-cur-predicate state)
292	node)
293	(parser-state-result state)))))
294	(('blank-node-property-list ('predicate-object-list po ...))
295	(let* ((node ((parser-state-blank-node-gen state)))
296	(new-state (parse-predicate-object
297	po (update-parser-state state #:cur-subject node))))
298	(update-parser-state new-state
299	#:cur-object node
300	#:cur-subject (parser-state-cur-subject state)
301	#:cur-predicate (parser-state-cur-predicate state)
302	#:result
303	(cons
304	(make-rdf-triple
305	(parser-state-cur-subject state)
306	(parser-state-cur-predicate state)
307	node)
308	(parser-state-result new-state)))))
309	('collection
310	(let ((object "http://www.w3.org/1999/02/22-rdf-syntax-ns#nil"))
311	(update-parser-state state
312	#:cur-object object
313	#:result
314	(cons
315	(make-rdf-triple
316	(parser-state-cur-subject state)
317	(parser-state-cur-predicate state)
318	object)
319	(parser-state-result state)))))
320	(('collection objects ...)
321	(let ((state (parse-collection objects state)))
322	(update-parser-state state
323	#:result
324	(cons
325	(make-rdf-triple
326	(parser-state-cur-subject state)
327	(parser-state-cur-predicate state)
328	(parser-state-cur-object state))
329	(parser-state-result state)))))
330	(('iri _)
331	(let* ((res (parse-iri object state))
332	(iri (assoc-ref res "iri"))
333	(state (assoc-ref res "state")))
334	(update-parser-state state
335	#:cur-object iri
336	#:result
337	(cons
338	(make-rdf-triple
339	(parser-state-cur-subject state)
340	(parser-state-cur-predicate state)
341	iri)
342	(parser-state-result state)))))))
343
344	(define (parse-collection collection state)
345	(let ((node ((parser-state-blank-node-gen state))))
346	(let loop ((objects collection)
347	(new-state
348	(update-parser-state state
349	#:cur-subject node
350	#:cur-predicate
351	"http://www.w3.org/1999/02/22-rdf-syntax-ns#first"))
352	(previous-object #nil))
353	(match objects
354	('()
355	(update-parser-state new-state
356	#:cur-object node
357	#:cur-subject (parser-state-cur-subject state)
358	#:cur-predicate (parser-state-cur-predicate state)
359	#:result
360	(cons
361	(make-rdf-triple
362	previous-object
363	"http://www.w3.org/1999/02/22-rdf-syntax-ns#rest"
364	"http://www.w3.org/1999/02/22-rdf-syntax-ns#nil")
365	(parser-state-result new-state))))
366	((('object object) objects ...)
367	(if (equal? previous-object #nil)
368	(let ((new-state (parse-object object new-state)))
369	(loop objects new-state node))
370	(let* ((node ((parser-state-blank-node-gen new-state)))
371	(new-state
372	(update-parser-state new-state
373	#:cur-subject node))
374	(new-state (parse-object object new-state)))
375	(loop
376	objects
377	(update-parser-state new-state
378	#:result
379	(cons
380	(make-rdf-triple
381	previous-object
382	"http://www.w3.org/1999/02/22-rdf-syntax-ns#rest"
383	node)
384	(parser-state-result new-state)))
385	node))))))))
386
387	(define (parse-object-list ol state)
388	(let loop ((ol ol) (state state))
389	(match ol
390	('() state)
391	((('object object) ol ...)
392	(loop ol (parse-object object state)))
393	((ol)
394	(loop ol state)))))
395
396	(define (parse-predicate-object po state)
397	(let loop ((po po) (state state))
398	(match po
399	((('verb verb) ('object-list ol ...) po)
400	(let* ((verb (parse-verb verb state))
401	(state (assoc-ref verb "state"))
402	(verb (assoc-ref verb "verb"))
403	(new-state (update-parser-state state #:cur-predicate verb))
404	(res (parse-object-list ol new-state)))
405	(loop po res)))
406	((('verb verb) ('object-list ol ...))
407	(let* ((verb (parse-verb verb state))
408	(state (assoc-ref verb "state"))
409	(verb (assoc-ref verb "verb"))
410	(new-state (update-parser-state state #:cur-predicate verb))
411	(res (parse-object-list ol new-state)))
412	res))
413	(((('verb verb) ('object-list ol ...)) po ...)
414	(let* ((verb (parse-verb verb state))
415	(state (assoc-ref verb "state"))
416	(verb (assoc-ref verb "verb"))
417	(new-state (update-parser-state state #:cur-predicate verb))
418	(res (parse-object-list ol new-state)))
419	(loop po res)))
420	('() state)
421	((po)
422	(loop po state)))))
423
424	(define (parse-subject s state)
425	(match s
426	(('iri _ ...)
427	(let ((res (parse-iri s state)))
428	`(("subject" . ,(assoc-ref res "iri"))
429	("state" . ,(assoc-ref res "state")))))
430	(('collection objects ...)
431	(let ((res (parse-collection objects state)))
432	`(("subject" . ,(parser-state-cur-object res))
433	("state" . ,res))))
434	('collection
435	`(("subject" . "http://www.w3.org/1999/02/22-rdf-syntax-ns#nil")
436	("state" . ,state)))
437	(('blank-node ('anon _))
438	(let ((node ((parser-state-blank-node-gen state))))
439	`(("subject" . ,node)
440	("state" . ,state))))
441	(('blank-node ('blank-node-label label))
442	(if (assoc-ref (parser-state-bnode-labels state) label)
443	`(("subject" . ,(assoc-ref (parser-state-bnode-labels state) label))
444	("state" . ,state))
445	(let ((node ((parser-state-blank-node-gen state))))
446	`(("subject" . ,node)
447	("state" . ,(update-parser-state state
448	#:bnode-labels
449	(cons
450	(cons label node)
451	(parser-state-bnode-labels state))))))))))
452
453	(define (parse-triples t state)
454	(match t
455	((('subject subject) ('predicate-object-list predicate-object ...))
456	(let* ((res (parse-subject subject state))
457	(subject (assoc-ref res "subject"))
458	(state (assoc-ref res "state"))
459	(state (update-parser-state state
460	#:cur-subject subject)))
461	(parse-predicate-object predicate-object state)))
462	((('blank-node-property-list ('predicate-object-list po ...))
463	('predicate-object-list predicate-object ...))
464	(let* ((subject ((parser-state-blank-node-gen state)))
465	(new-state (parse-predicate-object
466	po (update-parser-state state #:cur-subject subject))))
467	(parse-predicate-object predicate-object new-state)))
468	((('blank-node-property-list ('predicate-object-list po ...)))
469	(let* ((subject ((parser-state-blank-node-gen state))))
470	(parse-predicate-object po (update-parser-state state
471	#:cur-subject subject))))))
472
473	(define (parse-turtle-doc parse-tree state)
474	(let loop ((parse-tree parse-tree) (state state))
475	(match parse-tree
476	('() (parser-state-result state))
477	((('prefix-id ('pname-ns ns) ('iriref iri ...)) parse-tree ...)
478	(loop parse-tree
479	(add-ns-to-state
480	state ns (resolve-iri (parser-state-base-uri state)
481	(parse-string iri)))))
482	((('prefix-id ('pname-ns ('iriref iri ...))) parse-tree ...)
483	(loop parse-tree
484	(add-ns-to-state
485	state "" (resolve-iri (parser-state-base-uri state)
486	(parse-string iri)))))
487	((('sparql-prefix ('pname-ns ns) ('iriref iri ...)) parse-tree ...)
488	(loop parse-tree
489	(add-ns-to-state
490	state ns (resolve-iri (parser-state-base-uri state)
491	(parse-string iri)))))
492	((('sparql-prefix ('pname-ns ('iriref iri ...))) parse-tree ...)
493	(loop parse-tree
494	(add-ns-to-state
495	state "" (resolve-iri (parser-state-base-uri state)
496	(parse-string iri)))))
497	((('base ('iriref iri ...)) parse-tree ...)
498	(loop parse-tree
499	(update-parser-state
500	state #:base-uri (resolve-iri (parser-state-base-uri state)
501	(parse-string iri)))))
502	((('sparql-base ('iriref iri ...)) parse-tree ...)
503	(loop parse-tree
504	(update-parser-state
505	state #:base-uri (resolve-iri (parser-state-base-uri state)
506	(parse-string iri)))))
507	((('triples t ...) parse-tree ...)
508	(let ((res (parse-triples t state)))
509	(loop parse-tree (parse-triples t state))))
510	;; otherwise, it's a single element, not a list of statements
511	(((? symbol? _) _ ...) (loop (list parse-tree) state)))))
512
513	(define (tordf parse-tree base)
514	(define state
515	(make-parser-state base '() '() #f #f #f (create-generate-blank-node) '()))
516	(parse-turtle-doc parse-tree state))
517
518	(define (turtle->rdf str-or-file base)
519	(define str
520	(cond ((port? str-or-file) (get-string-all str-or-file))
521	((string? str-or-file) str-or-file)))
522	(let ((parse-tree (parse-turtle str)))
523	(tordf parse-tree base)))
524