1,079 research outputs found
Monadic parser combinators
In functional programming, a popular approach to building recursive descent parsers is to model parsers as functions, and to define higher-order functions (or combinators) that implement grammar constructions such as sequencing, choice, and repetition. Such parsers form an instance of a monad, an algebraic structure from mathematics that has proved useful for addressing a number of computational problems. The purpose of this report is to provide a step-by-step tutorial on the monadic approach to building functional parsers, and to explain some of the benefits that result from exploiting monads. No prior knowledge of parser combinators or of monads is assumed. Indeed, this report can also be viewed as a first introduction to the use of monads in programming
FliPpr: A Prettier Invertible Printing System
When implementing a programming language, we often write
a parser and a pretty-printer. However, manually writing both programs
is not only tedious but also error-prone; it may happen that a pretty-printed
result is not correctly parsed. In this paper, we propose FliPpr,
which is a program transformation system that uses program inversion
to produce a CFG parser from a pretty-printer. This novel approach
has the advantages of fine-grained control over pretty-printing, and easy
reuse of existing efficient pretty-printer and parser implementations
TRX: A Formally Verified Parser Interpreter
Parsing is an important problem in computer science and yet surprisingly
little attention has been devoted to its formal verification. In this paper, we
present TRX: a parser interpreter formally developed in the proof assistant
Coq, capable of producing formally correct parsers. We are using parsing
expression grammars (PEGs), a formalism essentially representing recursive
descent parsing, which we consider an attractive alternative to context-free
grammars (CFGs). From this formalization we can extract a parser for an
arbitrary PEG grammar with the warranty of total correctness, i.e., the
resulting parser is terminating and correct with respect to its grammar and the
semantics of PEGs; both properties formally proven in Coq.Comment: 26 pages, LMC
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