A scheme for lr(k) parsing with error recovery part iii: error correction

Abstract

The paper is the third in a series of three papers devoted to a detailed study of LR(k) parsing with error recovery and correction. A new class of syntax errors is introduced, called (k)-local parser defined errors, which suit better than the conventional minimum distance errors for characterization of error detection and recovery in LR(k) parsing. The question whether a given string has n k-local parser defined errors for some integer n is shown to be decidable. Using the formalization of LR(k) parsing and error recovery presented in the first and the second paper in the series it is shown that the canonical LR(k) parser of an LR(k) grammar always has an error recovering extension which is able to produce a correction for any terminal string containing only (k)-local parser defined errors.

Keywords:

• Formal systems
• context-free grammars
• canonical LR(k)
• LALR(k) and SLR(k) grammars and parsers
• error detection and recovery and correction
• minimum distance and parser defined errors

C.R. Categories:

• 4.12
• 5.23

†The work of this author was supported by the Emil Aaltonen Foundation.

†The work of this author was supported by the Emil Aaltonen Foundation.

Notes

†The work of this author was supported by the Emil Aaltonen Foundation.