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Language Processing Language Lexical Context Definition

IP.com Disclosure Number: IPCOM000109558D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Hidalgo, DS: AUTHOR

Abstract

Disclosed is a feature of the LANGUAGE PROCESSING LANGUAGE (LPL) that supports the definition of abstracted named sets of lexical rules that can be dynamically activated by a translator built with LPL in order to deal with input streams that have composite lexical requirements. These abstract lexical contexts are mechanically converted to lexical scanners within the generated lexical scanner function. (Image Omitted)

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Language Processing Language Lexical Context Definition

       Disclosed is a feature of the LANGUAGE PROCESSING
LANGUAGE (LPL) that supports the definition of abstracted named sets
of lexical rules that can be dynamically activated by a translator
built with LPL in order to deal with input streams that have
composite lexical requirements.  These abstract lexical contexts are
mechanically converted to lexical scanners within the generated
lexical scanner function.

                            (Image Omitted)

      For certain types of translators, such as those that process
embedded languages and other stream data processors, there is a need
to dynamically change the set of lexical rules that are applied to
the input stream in order to build syntactic units or tokens.  Such a
situation occurs, for instance, when fragments of the input stream
are written in a language different from that of the main portion of
the stream.  This is in fact the case for SQL precompilers.  The main
stream is written in the host language and SQL statements are
inserted in the host language module as fragments of a guest
language.  Since the lexical rules of the host language might be
different from those of the guest language, then the lexical scanner
processing the main input data stream must be able to apply the set
of lexical rules of the guest language to the guest language
fragments.

      This invention provides a syntactic facility for the LPL...