this article shows how such repairs can be found during shift-reduce parsing by using the parsing tables themselves. This results in a substantial space saving over methods that require precalculated tables. Furthermore, the article shows how the method can be integrated with lookahead to avoid finding repairs that immediately result in further syntax errors. The article presents the results of experiments on a version of the LALR(1)-based parser generator Bison to which the algorithm was added.

This paper describes a system that performs hierarchical error repair for illformed sentences, with heterarchical control of chart items produced at the lexical, syntactic, and semantic levels. The system uses an augmented context-free grammar and employs a bidirectional chart parsing algorithm. The system is composed of four subsystems: for lexical, syntactic, surface case, and semantic processing. The subsystems are controlled by an integrated-agenda system. The system employs a parser for well-formed sentences and a second parser for repairing single error sentences. The system ranks possible repairs by penalty scores which are based on both grammar-dependent factors (e.g. the significance of the repaired constituent in a local tree) and grammar-independent factors (e.g. error types). This paper focuses on the heterarchical processing of integratedagenda items (i.e. chart items) at three levels, in the context of single error recovery.

A compiler is a program that translates computer code into something the computer is able to understand. It will try to structure the computer code. The result of this can be seen as a tree structure on top of the code. The systems described in this thesis break these tree structures into pieces. These pieces are then sorted and counted. When some new code is oered for compilation, the systems try to build a new tree structure using the pieces of the previously encountered code. The pieces that have a higher count are more likely to be used in the structure. The compiler tries to build the new tree structure with pieces that have a high count. When the code which is being compiled contains an error, the compiler does not know what to do, because the pieces that are used to build the structure of the code are pieces of code that do not contain errors. The systems described here use certain techniques to correct the code in a way that the pieces with the highest count can be used to b...

Abstract—Modern integrated development environments (IDEs) offer recommendations to aid development, such as autocompletions, refactorings, and fixes for compilation errors. Recommendations for each code location are typically computed independently of the other locations. We propose that an IDE should consider the whole codebase, not just the local context, before offering recommendations for a particular location. We demonstrate the potential benefits of our technique by presenting four concrete scenarios in which the Eclipse IDE fails to provide proper Quick Fixes at relevant locations, even though it offers those fixes at other locations. We describe a technique that can augment an existing IDE’s recommendations to account for non-local information. For example, when some compilation errors depend on others, our technique helps the developer decide which errors to resolve first. I.

Local error repair of strings during C!FG parskg requires the insertion and de~etion of syrnbok in the region of a syntax error to produce a string that k error free. Rather than precalculating tables at parser generation time to assist in finding such repairs, this article shows how such repairs can be found during shifk-reduce parsing by using the parsing tables themselves. This resu~ts in a substantial space saving over methods that require precalculated tab~es. Furthermore, the article shows how the method can be integrated with Iookahead to avoid finding repairs that immediately result in further syntax errors. The article presents the resuks of experiments on a version of the LALR(l)-based parser generator Bison to which the algorlthm was added.

In this paper we present a scheme for detecting and recovering from syntax errors in programs. The scheme, which is based on LR parsing, is driven by information which is directly and automatically obtainable from the information that is already present in an LR parser. The approach, which is patterned after that of Levy and Graham and Rhodes, appears to provide error recovery which is both simple and powerful. Key Words and Phrases: programming languages, error correction, automatic correction, parsing, LR,

advantage, the copyright notice above and the title of the book appear, and notice is given

advantage, the copyright notice above and the title of the book appear, and notice is given