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SLE 2020
Sun 15 - Fri 20 November 2020 Online Conference
co-located with SPLASH 2020
Mon 16 Nov 2020 15:00 - 15:20 at SPLASH-III - Chair(s): Paddy Krishnan
Tue 17 Nov 2020 03:00 - 03:20 at SPLASH-III - Chair(s): Ralf Lämmel

Parsing Expression Grammars (PEGs) are a recognition-based formalism which allows to describe the syntactical and the lexical elements of a language. The main difference between Context-Free Grammars (CFGs) and PEGs relies on the interpretation of the choice operator: while the CFGs' unordered choice $e \mid e'$ is interpreted as the union of the languages recognized by $e$ and $e'$, the PEGs' prioritized choice $e / e'$ discards $e'$ if $e$ succeeds. Such subtle, but important difference, changes the language
recognized and yields more efficient parsing algorithms. This paper proposes a rewriting logic semantics for PEGs. We start
with a rewrite theory giving meaning to the usual constructs in PEGs. Later, we show that cuts, a mechanism for controlling backtracks in PEGs, finds also a natural representation in our framework.
We generalize such mechanism, allowing for both local and global cuts with a precise, unified and formal semantics. Hence, our work strives at better understanding and controlling backtracks in parsers for PEGs. The semantics we propose is executable and, besides being a parser with modest efficiency, it can be used as a playground to test different optimization ideas. More importantly, it is a mathematical tool that can be used for different analyses.

Mon 16 Nov
Times are displayed in time zone: Central Time (US & Canada) change

15:00 - 15:40: SLE at SPLASH-III +12h
Chair(s): Paddy KrishnanOracle Labs, Australia
15:00 - 15:20
Talk
SLE
Sergio Queiroz de MedeirosUniversidade Federal do Rio Grande do Norte, Carlos OlarteFederal University of Rio Grande do Norte, Brazil
Link to publication DOI Pre-print Media Attached
15:20 - 15:40
Talk
SLE
DOI Pre-print Media Attached

Tue 17 Nov
Times are displayed in time zone: Central Time (US & Canada) change

03:00 - 03:40: SLE at SPLASH-III
Chair(s): Ralf LämmelFacebook London
03:00 - 03:20
Talk
SLE
Sergio Queiroz de MedeirosUniversidade Federal do Rio Grande do Norte, Carlos OlarteFederal University of Rio Grande do Norte, Brazil
Link to publication DOI Pre-print Media Attached
03:20 - 03:40
Talk
SLE
DOI Pre-print Media Attached