FliPpr: A Prettier Invertible Printing System

Abstract

Abstract. 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 prettyprinted 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.

Fundamentals of reversible flowchart languages

“…A subject closely related to reversible programming is inverse computation and program inversion, e.g. [1,21,26,27,29,32,43]. Generalized program inversion generates a semi-inverse program, in the sense that, given some of the original inputs and outputs, it returns the remaining inputs and outputs [45,51].…”

Correct-by-construction pretty-printing

“…The following example is based on one discussed by Matsuda and Wang (2013). Expressions are defined inductively as follows:…”

“…This is the approach taken by Matsuda and Wang (2013), described in Sections 1 and 4.2. Matsuda and Wang outline the proof of a…”

“…In this case one is typically interested in at least one round-tripping property: the result of pretty-printing some value x, and then parsing the resulting string, should be x. Rendel and Ostermann (2010) argue that separate definitions of parsers and pretty-printers lead to redundancy and perhaps inconsistencies, and present combinators that allow the simultaneous definition of parsers and printers. Matsuda and Wang (2013) attack the problem in a somewhat different way. They show how, starting from an extended pretty-printer, one can use program inversion techniques to automatically derive a parser that satisfies the round-tripping property (assuming that the underlying grammar is unambiguous).…”

Composing Bidirectional Programs Monadically

“…Introducing monadic composition to BX programming significantly expands the expressiveness of BX languages and opens up a route for programmers to explore the connection between BX programming and mainstream uni-directional programming. Moreover, it appears that many applications of bidirectional transformations (e.g., parsers and printers [17]) do not share the lens get /put pattern, and as a result have not been sufficiently explored. However, monadic composition is known to be an effective way to construct at least one direction of such transformations (e.g., parsers).…”