NAME

       link-parser - parses natural language sentences

SYNOPSIS

       link-parser   [language]   [-pp  pp_knowledge_file]  [-c  constituent_knowledge_file]  [-a
       affix_file] [-ppoff] [-coff] [-aoff] [-batch] [-<special "!" command>]

DESCRIPTION

       In Selator, D. and Temperly, D. "Parsing English with a Link Grammar" (1991), the  authors
       defined a new formal grammatical system called a "link grammar". A sequence of words is in
       the language of a link grammar if there is a way to draw "links" between words in  such  a
       way  that  the  local requirements of each word are satisfied, the links do not cross, and
       the words form a consistent connected graph. The authors encoded English grammar into such
       a system, and wrote link-parser to parse English using this grammar.

       This  package  can  be used for linguistic parsing for information retrieval or extraction
       from natural language documents. Abiword also uses it as a grammar checker.

OPTIONS

       -pp pp_knowledge_file

       -c constituent_knowledge_file

       -a affix_file

       -ppoff

       -coff

       -aoff

       -batch

       -<special ! command>

USE

       link-parser, when invoked manually, will take control of the  terminal;  link-parser  will
       then attempt to analyze the grammar of all input, unless escaped with an exclamation mark,
       according to the dictionary file provided as an argument. If escaped, the  input  will  be
       treated as a "special command"; "!help" lists all special commands available.

       link-parser  depends  on  a  link-grammar  dictionary  which  contains  lists of words and
       associated metadata about their grammatical properties in order to  analyze  sentences.  A
       link-grammar  dictionary  provided by the authors of link-grammar is usually included with
       the link-grammar package, and can often be found somewhere in the /usr/share/link-grammar/
       hierarchy.  When this is the case, only the two-letter language code needs to be specified
       on the command-line.  Alternatively, a  user  can  provide  their  own  dictionary  as  an
       argument,  in  which case the dictionary's directory should be specified. Hence, either of
       the commands

       link-parser en

       link-parser /usr/share/link-grammar/en
              will run link-parser using the english dictionary included with the parser.

       While in a link-parser session, some example output could be:

              linkparser> Reading a man page is informative.

              ++++Time                                          0.00 seconds (0.01 total)

              Found 1 linkage (1 had no P.P. violations)
                Unique linkage, cost vector = (UNUSED=0 DIS=0 AND=0 LEN=12)

                  +------------------------Xp-----------------------+
                  |         +---------Ss*g---------+                |
                  |         +-------Os-------+     |                |
                  |         |     +----Ds----+     |                |
                  +----Wd---+     |   +--AN--+     +---Pa---+       |
                  |         |     |   |      |     |        |       |

              LEFT-WALL reading.g a man.n page.n is.v informative.a .

       A P.P. violation is a post-processing violation; it is a post-linkage step used to  reject
       invalid  parses.  The  link types shown are specific to English; other langauges will have
       different link types.

       link-parser can also be used non-interactively, either through its API, or via the  -batch
       option.   When  used  with  the  -batch  option, link-parser passively receives input from
       standard input, and when the stream finishes, it then outputs its analysis. So  one  could
       construct  an  ad-hoc  grammar  checker  by  piping  text through link-parser with a batch
       option, and seeing what sentences fail to parse as valid:
              cat thesis.txt | link-parser /usr/share/link-grammar/en/4.0.dict -batch

SEE ALSO

       Information on the shared-library API and the link types used in the parse is  avavailable
       at the Abiword website at http://www.abisource.com/projects/link-grammar/dict/index.html
       Peer-reviewed  papers  explaining  link-parser  can  be  found at the original CMU site at
       http://www.link.cs.cmu.edu/link/papers/index.html.

AUTHOR

       link-parser  was  written  by  Daniel   Sleator   <sleator@cs.cmu.edu>,   Davy   Temperley
       <dtemp@theory.esm.rochester.edu>, and John Lafferty <lafferty@cs.cmu.edu>

       This  manual page was written by Ken Bloom <kbloom@gmail.com>, for the Debian project (but
       may be used by others).

                                          April 18, 2008                          LINK-GRAMMAR(1)