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link grammar

Chicken bindings to the CMU link grammar parser.

Description

The link grammar parser is a syntactic parser of English, based on link grammar, an original theory of English syntax. Given a sentence, the system assigns to it a syntactic structure, which consists of a set of labeled links connecting pairs of words. The parser also produces a "constituent" representation of a sentence (showing noun phrases, verb phrases, etc.).

Author

David Ireland

Example

(require-extension link-grammar)

(define (display-linkage sentence opts index)
  (let* ([links-found (lg:linkages-found sentence)]
         [linkage (lg:create-linkage index sentence opts)])
    (when linkage
      (begin
        (let ([constituents (lg:get-constituents linkage lg:MAX-STYLES)]
              [diagram      (lg:get-diagram linkage #t 80)])
          (print "Constituents(" index ") -> " constituents)
          (print "Diagram(" index ") -> "  diagram)
          (lg:delete-linkage linkage))))
    (when (<= index links-found)
      (display-linkage sentence opts (+ index 1)))))
 
(define (parse text dictionary opts)
  (let* ([sentence     (lg:create-sentence text dictionary)]
         [num-linkages (lg:parse-sentence sentence opts)])
    (when (= num-linkages 0)
      (begin
       (lg:set-min-null-count! opts  1)
       (lg:set-max-null-count! opts (lg:sentence-length sentence))
       (set! num-linkages (lg:parse-sentence sentence opts))))
    (display-linkage sentence opts 0)
    (lg:delete-sentence sentence)))


; Main Entry
(define dictionary (lg:create-default-dictionary))
(define opts       (lg:init-opts))

(lg:set-linkage-limit!  opts 1000)
(lg:set-short-length!   opts 10)
(lg:set-verbosity!      opts 1) 
(lg:set-max-parse-time! opts 30)
(lg:set-linkage-limit!  opts 1000)
(lg:set-min-null-count! opts 0)
(lg:set-max-null-count! opts 0)
(lg:set-short-length!   opts 16)
(lg:set-islands-ok!     opts #f)

(parse "The black fox ran from the hunters" dictionary opts)

Produces the following output:

Constituents(0) -> (S (NP the black.a fox.n)
   (VP ran.v-d
       (PP from
           (NP the hunters.n))))

Diagram(0) -> 
   +------------------------Xp------------------------+       
   +----------->WV----------->+                       |       
   +---------Wd--------+      |                       |       
   |      +----Ds**x---+      |      +----Jp----+     |       
   |      |     +---A--+--Ss--+--MVp-+   +--Dmc-+     +--RW--+
   |      |     |      |      |      |   |      |     |      |
LEFT-WALL the black.a fox.n ran.v-d from the hunters.n . RIGHT-WALL 

Constituents(1) -> (S (NP the black.a fox.n)
   (VP ran.v-d
       (PP from
           (NP the hunters.n))))

Diagram(1) -> 
   +------------------------Xp------------------------+       
   +---------Wd--------+                              |       
   |      +----Ds**x---+             +----Jp----+     |       
   |      |     +---A--+--Ss--+--MVp-+   +--Dmc-+     +--RW--+
   |      |     |      |      |      |   |      |     |      |
LEFT-WALL the black.a fox.n ran.v-d from the hunters.n . RIGHT-WALL 

API

System Information

[procedure] (lg:get-version) -> string
[procedure] (lg:get-dictionary-version dictionary*) -> string
[procedure] (lg:get-dictionary-locale) dictionary*) -> string

Dictionary

[procedure] (lg:create-default-dictionary) -> dictionary*
[procedure] (lg:create-dictionary-from-utf8 string) -> dictionary*
[procedure] (lg:create-dictionary-with-language string) -> dictionary*
[procedure] (lg:get-dictionary-language dictionary*) -> string
[procedure] (lg:get-dictionary-data-dir dictionary*) -> string
[procedure] (lg:set-dictionary-data-dir! string)
[procedure] (lg:delete-dictionary! dictionary*)

Parse Options

[procedure] (lg:init-opts parse-options* int) -> parse-options*
[procedure] (lg:set-max-parse-time! parse-options* int)
[procedure] (lg:set-linkage-limit! parse-options* int)
[procedure] (lg:set-short-length! parse-options* int)
[procedure] (lg:set-disjunct-cost! parse-options* int)
[procedure] (lg:set-min-null-count! parse-options* int)
[procedure] (lg:set-max-null-count! parse-options* int)
[procedure] (lg:set-max-parse-time! parse-options* int)
[procedure] (lg:set-islands-ok! parse-options* bool)
[procedure] (lg:set-verbosity! parse-options* int)
[procedure] (lg:get-verbosity parse-options*) -> int
[procedure] (lg:resources-exhausted? parse-options*) -> bool
[procedure] (lg:memory-exhausted? parse-options*) -> bool
[procedure] (lg:timer-expired? parse-options*) -> bool
[procedure] (lg:reset-resources! parse-options*)
[procedure] (lg:delete-parse-options! parse-options*)

Sentences

[procedure] (lg:create-sentence string dictionary*) -> sentence*
[procedure] (lg:split-sentence sentence* parse-options*) -> int
[procedure] (lg:parse-sentence sentence* parse-options*) -> int
[procedure] (lg:sentence-length sentence*) -> int
[procedure] (lg:sentence-null-count sentence*) -> int
[procedure] (lg:sentence-disjunct-cost sentence* int) -> int
[procedure] (lg:sentence-link-cost sentence* int) -> int
[procedure] (lg:linkages-found sentence*) -> int
[procedure] (lg:linkages-post-processed sentence*) -> int
[procedure] (lg:linkages-violated sentence* int) -> int
[procedure] (lg:valid-linkages sentence*) -> int
[procedure] (lg:delete-sentence! sentence*)

Linkages

[procedure] (lg:create-linkage int sentence* parse-options*) -> int
[procedure] (lg:corpus-cost linkage*) -> double
[procedure] (lg:get-lword linkage* int) -> int
[procedure] (lg:get-rword linkage* int) -> int
[procedure] (lg:get-words linkage*) -> list
[procedure] (lg:get-word linkage* int) -> string
[procedure] (lg:get-constituents linkage* int) -> string
[procedure] (lg:get-diagram linkage* bool int) -> string
[procedure] (lg:get-postscript inkage* bool bool) -> string
[procedure] (lg:get-disjuncts linkage*) -> string
[procedure] (lg:get-links-domains linkage*) -> string
[procedure] (lg:get-pp-msgs linkage*) -> string
[procedure] (lg:get-senses linkage*) -> string
[procedure] (lg:get-violation-name linkage*) -> string
[procedure] (lg:link-length linkage* int) -> int
[procedure] (lg:link-label linkage* int) -> int
[procedure] (lg:link-llabel linkage* int) -> int
[procedure] (lg:link-rlabel linkage* int) -> int
[procedure] (lg:link-cost linkage*) -> int
[procedure] (lg:link-domain-names linkage* int) -> list
[procedure] (lg:num-words linkage*) -> int
[procedure] (lg:num-links linkage*) -> int
[procedure] (lg:num-domains linkage* int) -> int
[procedure] (lg:unused-word-cost linkage*) -> int
[procedure] (lg:delete-linkage linkage*)

Changelog

• 1.0 Initial Release

License

This program 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 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 program; if not, 
write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA