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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

 
(import link-grammar)

(define (process-linkage sentence opts)
  (let* ([verbosity   (lg:get-verbosity opts)]
         [links-found (lg:linkages-found sentence)]
         [max-links   1024]
         [index       0])
    (print "Verbosity: " verbosity)
    (print "Links found: " links-found)

    (define (display-linkage sentence opts index)
      (let* ([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)))))
    (display-linkage sentence opts 0)))

(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))))
    (process-linkage sentence opts)))

(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." opts)

API

System Initialization

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

Linkages