In this paper, we present an efficient, functional, and formally verified parsing algorithm for LL(1) context-free expressions based on the concept of derivatives of formal languages.
Parsing with derivatives is an elegant parsing technique, which, in the general case, suffers from cubic worst-case time complexity and slow performance in practice.
We specialise the parsing with derivatives algorithm to LL(1) context-free expressions, where alternatives can be chosen given a single token of lookahead.
We formalise the notion of LL(1) expressions and show how to efficiently check the LL(1) property.
Next, we present a novel linear-time parsing with derivatives algorithm for LL(1) expressions operating on a zipper-inspired data structure.
We prove the algorithm correct in Coq and present an implementation as a part of Scallion, a parser combinators framework in Scala with enumeration and pretty printing capabilities.
Fri 19 Jun Times are displayed in time zone: (GMT-07:00) Pacific Time (US & Canada) change
|06:20 - 06:40|
Grzegorz HermanJagiellonian University, Poland
|06:40 - 07:00|
|07:00 - 07:20|
|07:20 - 07:40|