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Language Processing Language, Lexical Scanner Definition

IP.com Disclosure Number: IPCOM000108222D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Hidalgo, DS: AUTHOR

Abstract

Disclosed is a feature of the LANGUAGE PROCESSING LANGUAGE (LPL) that supports the interfacing of a Lexical Scanner mechanically generated from an LDF (Language Definition File) with manually written code to form a translator for a formal language. A formal language definition must include the set of rules that governs the construction of user- defined symbols in that language. This set of rules is sometimes referred to as Lexical Rules and their implementation function is most often called a Lexical Scanner.

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Language Processing Language, Lexical Scanner Definition

       Disclosed is a feature of the LANGUAGE PROCESSING
LANGUAGE (LPL) that supports the interfacing of a Lexical Scanner
mechanically generated from an LDF (Language Definition File) with
manually written code to form a translator for a formal language. A
formal language definition must include the set of rules that governs
the construction of user- defined symbols in that language. This set
of rules is sometimes referred to as Lexical Rules and their
implementation function is most often called a Lexical Scanner.

      Although there are tools that provide sophisticated ways of
defining lexical rules for automatic implementation, these rules are
not readily related to the rest of the definition of the language.
Since the set of lexical rules is closely related to the set of
predefined symbols and the set of syntactic rules, it is necessary to
integrate their definitions with the rest of the basic language
design so that LPL's goal of automatic design consistency management
can be achieved.

      Since the code generated from the Lexical Section definition
needs to be interfaced with the manually written code, a means for
doing so must be provided by LPL. The feature hereby disclosed
provides the user the flexibility to define a name for the lexical
function generated by an LPL translator so that the user may
reference this function through the given name in the manually
written source code. The synta...