Accession Number : ADA122152


Title :   Incremental Expression Parsing for Syntax-Directed Editors


Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF COMPUTER SCIENCE


Personal Author(s) : Kaiser, Gail E ; Kant, Elaine


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA122152


Report Date : 27 Oct 1982


Pagination or Media Count : 57


Abstract : This document describes an algorithm for incremental parsing of expressions in the context of syntax-directed editors for programming languages. Since a syntax-directed editor represents programs as trees and statements and expressions as nodes in trees, making minor modifications in an expression can be difficult. To make these changes in a typical syntax-directed editor, the user must understand the tree structure and type a number of tree-oriented construction and manipulation commands. This document describes an algorithm that allows the user to think in terms of the syntax of the expression as it is displayed on the screen (in infix notation) rather than in terms of its internal representation (which is effectively prefix), while maintaining the benefits of syntax-directed editing. The time and space complexities of the modifications for each new token are linear in the depth of the syntax tree.


Descriptors :   *ALGORITHMS , *EDITING , *PARSERS , *PROGRAMMING LANGUAGES , GLOBAL , INTERACTIONS , INTERFACES , SYNTAX , TRANSFORMATIONS , TREES , USER NEEDS


Subject Categories : Theoretical Mathematics
      Computer Programming and Software


Distribution Statement : APPROVED FOR PUBLIC RELEASE