frown: LALR(k) parser generator

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Frown is an LALR(k) parser generator for Haskell 98 written in Haskell 98. Its salient features are: • The generated parsers are time and space efficient. On the downside, the parsers are quite large. • Frown generates four different types of parsers. as a common characteristic, the parsers are genuinely functional (ie ‘table-free’); the states of the underlying LR automaton are encoded as mutually recursive functions. Three output formats use a typed stack representation, and one format due to Ross Paterson (code=stackless) works even without a stack. • Encoding states as functions means that each state can be treated individually as opposed to a table-driven approach, which necessitates a uniform treatment of states. For instance, look-ahead is only used when necessary to resolve conflicts. • Frown comes with debugging and tracing facilities; the standard output format due to Doaitse Swierstra (code=standard) may be useful for teaching LR parsing. • Common grammatical patterns such as repetition of symbols can be captured using rule schemata. There are several predefined rule schemata. • Terminal symbols are arbitrary variable-free Haskell patterns or guards. Both terminal and nonterminal symbols may have an arbitrary number of synthesized attributes. • Frown comes with extensive documentation; several example grammars are included. Furthermore, Frown supports the use of monadic lexers, monadic semantic actions, precedences, and associativity, the generation of backtracking parsers, multiple start symbols, error reporting, and a weak form of error correction.


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Versions [RSS] 0.6, 0.6.2,,,
Dependencies base (<4.10), directory [details]
License LicenseRef-GPL
Author Ralf Hinze
Uploaded by MatthewFarkasDyck at 2016-03-06T07:47:40Z
Reverse Dependencies 1 direct, 0 indirect [details]
Executables frown
Downloads 3482 total (13 in the last 30 days)
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Status Docs not available [build log]
Last success reported on 2016-11-27 [all 3 reports]