A parser for natural language text

Claim 2

A data processing method (70, 76) for parsing natural language text, characterized by the steps of: inputting (74) a human language word string; isolating word components (20) of said input string; performing a first morphological analysis (22) of the isolated words from said input string, to strip off prefixes and suffixes; looking up in a dictionary (24, 72) all the possible parts of speech for each word in said input stream; performing a second morphological analysis (26) on words from said input data stream which are not successfully matched in said dictionary look-up; applying complement grammar rules (28) to eliminate impossible parts of speech from consideration based upon the context within which the words of the input data stream occur; resolving ambiguities (30) in those words which require consideration of semantic as well as syntactic characteristics; selecting those words identified as verbs and grouping them according to valid verb group sequences (32); performing a clause analysis (34) including a verb complement analysis (36), a noun phrase determination (38), a prepositional phrase structure determination (40) and a grammar violation analysis (42); and outputting (78) a data structure where the words from the input data stream are associated with parts of speech and with group markings that indicate phrase structure.

Claim 3

A data processing method for parsing natural language text according to Claim 1, in a computer (76) having a memory, characterized by the steps of: isolating word components of said input word string (20) in a bidirectional list data structure; said list data structure being a plurality of list nodes (L) stored in said memory, each list node including a first address pointer to a preceding list node and a second address pointer to a succeeding list node in said list data structure; said list data structure further including string nodes (S) stored in said memory, each of the string nodes being pointed to by a corresponding one of said list nodes, said string node storing information relating to a character string stored in said memory representing one of said isolated word components; said list data structure further including property nodes (P) stored in said memory, each said property node being pointed to by a corresponding one of said string nodes stored in said memory, said property nodes storing information relating to the language attributes of said character string representing said one of said isolated word components; looking up in a dictionary (24, 72) stored in association with said computer, the language attributes for one of said isolated word components associated with one of said string nodes and storing information accessed from said dictionary in response thereto, in association with one of said property nodes pointed to by said one of said string nodes; performing an analysis (28-42) of said input word stream by accessing said list nodes in both a forward and a backward direction along said list data structure, accessing said string nodes pointed to by said accessed list nodes, accessing said property nodes pointed to by said accessed string nodes, and processing in context said character strings and their language attributes relating to said accessed string nodes and property nodes in accordance with stored program instructions for carrying out said analysis; and outputting the results of said analysis; whereby an analysis can be made using the context within which words occur in the input word string.

Claim 4

A data processing method for parsing natural language text, comprising the steps of: inputting a human language word string; isolating word components (20) of said input strings; performing a morphological analysis (22) of the isolated words from said input string, to strip off prefixes and suffixes; looking up in a dictionary (24) all the possible parts of speech for each word in said input stream; applying complement grammar rules (28) to eliminate impossible parts of speech from consideration based upon the context within which the words of the input data stream occur; and outputting a data structure where the words from the input data stream are associated with parts of speech.

Claim 5

A data processing method for parsing natural language text, comprising the steps of: inputting a human language word string; isolating word components (20) of said input strings; performing a morphological analysis (22) of the isolated words from said input string, to strip off prefixes and suffixes; looking up in a dictionary (24) all the possible parts of speech for each word in said input stream; applying complement grammar rules (28) to eliminate impossible parts of speech from consideration based upon the context within which the words of the input data stream occur; and outputting a data structure where the words from the input data stream are associated with parts of speech.

Claim 6

A data processing method for parsing natural language text in a computer having a memory, comprising the steps of: inputting a human language word string; isolating word components of said input word string in a bidirectional list data structure; said list data structure being a plurality of list nodes stored in said memory, including a first list node having a first backward address pointer to a base list node and a first forward address pointer to a second list node in said list data structure, and a first string address pointer; said second list node including a second backward address pointer to said first list node and a second forward address pointer to a succeeding list node in said list data structure, and a second string address pointer; said list data structure further including a first string node stored in said memory pointed to by said first string address pointer, for storing information relating to a first character string stored in said memory representing a first one of said isolated word components, and further including a first property address pointer; said list data structure further including a second string node stored in said memory pointed to by said second string address pointer, for storing information relating to a second character string stored in said memory representing a second one of said isolated word components, and further including a second property address pointer; said list data structure further including a first property node stored in said memory pointed to by said first property address pointer, for storing information relating to first language attributes of said first character string; said list data structure further including a second property node stored in said memory pointed to by said second property address pointer, for storing information relating to second language attributes of said second character string; performing a word context analysis of said input word stream by accessing said first and second list nodes in sequence of both a forward and a backward scanning direction along said list data structure, accessing said first and second string nodes pointed to by said accessed first and second list nodes, accessing said first and second property nodes pointed to by said accessed first and second string nodes, and processing in context said first and second character strings and said first and second language attributes in accordance with stored program instructions for carrying out said word context analysis; and outputting the results of said analysis; whereby an analysis can be made using the context within which words occur in the input word string.

Claim 7

A data processing method for parsing natural language text in a computer having a memory, comprising the steps of: inputting a human language word string; isolating word components of said input word string in a bidirectional list data structure; said list data structure being a plurality of list nodes stored in said memory, including a first list node having a first backward address pointer to a base list node and a first forward address pointer to a second list node in said list data structure, and a first string address pointer; said second list node including a second backward address pointer to said first list node and a second forward address pointer to a succeeding list node in said list data structure, and a second string address pointer; said list data structure further including a first string node stored in said memory pointed to by said first string address pointer, for storing information relating to a first character string stored in said memory representing a first one of said isolated word components, and further including a first property address pointer; said list data structure further including a second string node stored in said memory pointed to by said second string address pointer, for storing information relating to a second character string stored in said memory representing a second one of said isolated word components, and further including a second property address pointer; said list data structure further including a first property node stored in said memory pointed to by said first property address pointer, for storing information relating to first language attributes of said first character string; said list data structure further including a second property node stored in said memory pointed to by said second property address pointer, for storing information relating to second language attributes of said second character string; performing a word context analysis of said input word stream by accessing said first and second list nodes in sequence of both a forward and a backward scanning direction along said list data structure, accessing said first and second string nodes pointed to by said accessed first and second list nodes, accessing said first and second property nodes pointed to by said accessed first and second string nodes, and processing in context said first and second character strings and said first and second language attributes in accordance with stored program instructions for carrying out said word context analysis; and outputting the results of said analysis; whereby an analysis can be made using the context within which words occur in the input word string.

Claim 8

The data processing method for parsing natural language text of Claim 4, wherein said word context analysis step comprises the steps of: applying complement grammar rules (28) to eliminate impossible parts of speech from consideration based upon the context within which said first and second word components of the input data stream occur; and outputting a data structure where the words from the input data stream are associated with parts of speech.

Claim 9

The data processing method for parsing natural language text of Claim 4 or 5, wherein said word context analysis step further comprises the steps of: applying verb group analysis (32) to identify verb groups based upon the context within which said first and second word components of the input data stream occur; and outputting a data structure where the words from the input data stream are associated with parts of speech.

Claim 10

The data processing method for parsing natural language text of Claim 6, wherein said verb group analysis includes the step of applying paradigm-based morphological text analysis to identify the grammatical category of said first or said second word component.

Claim 11

The data processing method for parsing natural language text of any of Claims 4-7, wherein said word context analysis step further comprises the steps of: applying clause analysis (34) to identify constituent clauses based upon the context within which said first and second word components of the input data stream occur; outputting a data structure where the words and phrases from the input data stream are associated with parts of speech.