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Island Grammar-based Parsing using GLL and Tom

Abstract : Extending a language by embedding within it another language presents significant parsing challenges, especially if the embedding is recursive. The composite grammar is likely to be nondeterministic as a result of tokens that are valid in both the host and the embedded language. In this paper we examine the challenges of embedding the Tom language into a variety of general-purpose high level languages. Tom provides syntax and semantics for advanced pattern matching and tree rewriting facilities. Embedded Tom constructs are translated into the host language by a preprocessor, the output of which is a composite program written purely in the host language. Tom implementations exist for Java, C, C#, Python and Caml. The current parser is complex and difficult to maintain. In this paper, we describe how Tom can be parsed using island grammars implemented with the Generalised LL (GLL) parsing algorithm. The grammar is, as might be expected, ambiguous. Extracting the correct derivation relies on our disambiguation strategy which is based on pattern matching within the parse forest. We describe different classes of ambiguity and propose patterns for resolving them.
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Contributor : Jean-Christophe Bach Connect in order to contact the contributor
Submitted on : Tuesday, September 11, 2012 - 8:45:40 AM
Last modification on : Saturday, June 25, 2022 - 7:45:18 PM
Long-term archiving on: : Friday, December 16, 2016 - 11:58:55 AM


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Ali Afroozeh, Jean-Christophe Bach, Mark van den Brand, Adrian Johnstone, Maarten Manders, et al.. Island Grammar-based Parsing using GLL and Tom. SLE 2012 - 5th International Conference on Software Language Engineering, Sep 2012, Dresden, Germany. pp.224-243, ⟨10.1007/978-3-642-36089-3_13⟩. ⟨hal-00722878v2⟩



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