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)