aboutsummaryrefslogtreecommitdiff
path: root/xapian/xapian.scm
blob: 75924aed0ae182b218e2dfac1bfd8dfb6cbb1ca1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
;;; guile-xapian --- Guile bindings for Xapian
;;; Copyright © 2020, 2022 Arun Isaac <arunisaac@systemreboot.net>
;;; Copyright © 2021 Bob131 <bob@bob131.so>
;;;
;;; This file is part of guile-xapian.
;;;
;;; guile-xapian 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.
;;;
;;; guile-xapian 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 guile-xapian.  If not, see
;;; <https://www.gnu.org/licenses/>.

(define-module (xapian xapian)
  #:use-module (rnrs arithmetic bitwise)
  #:use-module (rnrs bytevectors)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-26)
  #:use-module (xapian wrap)
  #:export (xapian-open
            xapian-close
            call-with-database
            database-document-count
            xapian-open-writable
            xapian-close-writable
            call-with-writable-database
            call-with-in-memory-database
            add-document!
            replace-document!
            make-document
            document-data
            document-bytes
            document-set-data!
            document-set-bytes!
            document-slot-ref
            document-slot-ref-bytes
            document-slot-set!
            document-slot-set-bytes!
            make-stem
            make-term-generator
            index-text!
            increase-termpos!
            parse-query
            enquire
            enquire-mset
            mset-item-docid
            mset-item-document
            mset-item-rank
            mset-item-weight
            mset-fold
            mset-snippet))

(define xapian-open new-Database)
(define xapian-close delete-Database)

(define (call-with-database dbpath proc)
  (let ((db (xapian-open dbpath)))
    (dynamic-wind noop (cut proc db) (cut xapian-close db))))

(define database-document-count Database-get-doccount)

(define xapian-open-writable new-WritableDatabase)
(define xapian-close-writable delete-WritableDatabase)

(define (call-with-writable-database dbpath proc)
  (let ((db (xapian-open-writable dbpath)))
    (dynamic-wind noop (cut proc db) (cut xapian-close-writable db))))

(define (call-with-in-memory-database proc)
  "Call PROC passing it an in-memory writable database. Only a
writable in-memory database can be created, since a read-only
in-memory database would always remain empty and is of little use."
  (let ((db (inmemory-open)))
    (dynamic-wind noop (cut proc db) (cut xapian-close-writable db))))

(define add-document! WritableDatabase-add-document)
(define replace-document! WritableDatabase-replace-document)

(define* (make-document #:key data (terms '()) (values '()))
  (let ((doc (new-Document)))
    (when data
      (document-set-data! doc data))
    (for-each (match-lambda
                ((term . wdf-increment)
                 (Document-add-term doc term wdf-increment)))
              terms)
    (for-each (match-lambda
                ((slot . value)
                 (document-slot-set! doc slot value)))
              values)
    doc))

(define document-data Document-get-data)
(define document-bytes Document-get-data-bytes)

(define (document-set-data! document data)
  "Set data of DOCUMENT to DATA. DATA may be a string or a bytevector."
  (cond
   ((string? data)
    (Document-set-data document data))
   ((bytevector? data)
    (Document-set-data-bytes document data))
   (else
    (error "Invalid document data" data))))

(define (document-set-bytes! doc data)
  (display "document-set-bytes! is deprecated. document-set-data! now supports setting bytevectors as data. Please use that instead."
           (current-error-port))
  (Document-set-data-bytes doc data))

(define document-slot-ref Document-get-value)
(define document-slot-ref-bytes Document-get-value-bytes)

(define (document-slot-set! document slot value)
  "Set SLOT of DOCUMENT to VALUE. VALUE may be a string or a
bytevector."
  (cond
   ((string? value)
    (Document-add-value document slot value))
   ((bytevector? value)
    (Document-add-value-bytes document slot value))
   (else
    (error "Invalid document slot value" value))))

(define (document-slot-set-bytes! document slot value)
  (display "document-slot-set-bytes! is deprecated. document-slot-set! now supports setting bytevectors as slot value. Please use that instead."
           (current-error-port))
  (Document-add-value-bytes document slot value))

(define make-stem new-Stem)

(define* (make-term-generator #:key stem document)
  (let ((term-generator (new-TermGenerator)))
    (TermGenerator-set-stemmer term-generator stem)
    (TermGenerator-set-document term-generator document)
    term-generator))

(define* (index-text! term-generator text #:key (wdf-increment 1) prefix)
  (apply TermGenerator-index-text term-generator text wdf-increment
         (if prefix (list prefix) '())))

(define increase-termpos! TermGenerator-increase-termpos)

(define* (parse-query querystring #:key stemmer stemming-strategy (prefixes '()))
  (let ((queryparser (new-QueryParser)))
    (QueryParser-set-stemmer queryparser stemmer)
    (when stemming-strategy
      (QueryParser-set-stemming-strategy queryparser stemming-strategy))
    (for-each (match-lambda
                ((field . prefix)
                 (QueryParser-add-prefix queryparser field prefix)))
              prefixes)
    (let ((query (QueryParser-parse-query queryparser querystring)))
      (delete-QueryParser queryparser)
      query)))

(define* (enquire db query #:key weighting-scheme)
  (let ((enquire (new-Enquire db)))
    (Enquire-set-query enquire query)
    (when weighting-scheme
      (Enquire-set-weighting-scheme enquire weighting-scheme))
    enquire))

(define* (enquire-mset enquire #:key (offset 0) maximum-items)
  "Run a query using the settings in the ENQUIRE object and return an
mset object.

OFFSET specifies the number of items to ignore at the beginning of the
result set.

MAXIMUM-ITEMS specifies the maximum number of items to return. To
return all matches, pass the result of calling database-document-count
on the database object."
  (Enquire-get-mset enquire offset maximum-items))

(define mset-item-docid MSetIterator-get-docid)
(define mset-item-document MSetIterator-get-document)
(define mset-item-rank MSetIterator-get-rank)
(define mset-item-weight MSetIterator-get-weight)

(define (mset-fold proc init mset)
  (let loop ((head (MSet-begin mset))
             (result init))
    (cond
     ((MSetIterator-equals head (MSet-end mset)) result)
     (else (let ((result (proc head result)))
             (MSetIterator-next head)
             (loop head result))))))

(define (get-flag flag-thunk value)
  (if value (flag-thunk) 0))

;; TODO: Support cjk-words?
(define* (mset-snippet mset text
                       #:key (length 500) (stemmer (make-stem "none"))
                       (highlight-start "<b>") (highlight-end "</b>") (omit "...")
                       (background-model? #t) (exhaustive? #t)
                       (empty-without-match? #t)
                       (cjk-ngram? #t))
  (MSet-snippet mset text length stemmer
                (bitwise-ior (get-flag MSet-SNIPPET-BACKGROUND-MODEL background-model?)
                             (get-flag MSet-SNIPPET-EXHAUSTIVE exhaustive?)
                             (get-flag MSet-SNIPPET-EMPTY-WITHOUT-MATCH empty-without-match?)
                             (get-flag MSet-SNIPPET-CJK-NGRAM cjk-ngram?))
                highlight-start highlight-end omit))