Formal ambiguity-resolving syntax denition with asserted shift reduce sets

There are parser generators that accept ambiguous context-free grammars,where ambiguities are resolved via disambiguation rules, with the outcome of smaller parsetables and more ecient parsers. however, the compiler writers are expected to developcompact ambiguous grammars and extract ambiguity-resolving information from the syntaxand semantics of the language. the aforementioned tasks require considerable expertise,not often owned by casual compiler writers, or even expert programmers who are assigneda serious compiler-writing task, while programming language designers are usually capableof providing a concise and compact ambiguous description of the language that may includeambiguity-resolving information. in this paper, we aim to provide a powerful notation forsyntax denition, which enables the language designer to assert some shifts and reducesets associated with each production rule of the possibly ambiguous grammar. these setsof language tokens guide the parser generator to resolve the parse table conicts thatare caused by the ambiguities in the grammar or by other sources. the practicality ofthe proposed asserted shift reduce notation is supported by several examples from theconstructs of contemporary programming languages, and is tested to work properly viadeveloping a parser generator that constructs conict-free lalr (1) parse tables.