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The latest version of syntax is 1.0.0.0-2.

syntax

Version 1.0.0.0 revision 1 uploaded by pawel834.

Package meta

Synopsis
Reversible parsing and pretty-printing.
Description

UPDATE: I have a lot of work now and so I haven't updated the library in a while. However once I get some free time I will probably rewrite it with a new, cleaner design (focused more on adjoints then isomorphisms). Consider this package very experimental :)

"syntax" allows you to write a single syntax description and instantiate is both as a parser and a pretty printer.

Syntax descriptions are written in applicative or arrow style. The library uses a custom typeclass hierarchy, provided by the "semi-iso" package. Most of the time you will be using operators like /$/, /*/ and /+/ (= <|>), just like parser combinators. When more power is needed - e.g. when the syntax depends on the parsed or printed value - you turn to arrows.

Semi-isomorphisms from "semi-iso" are the basic building block of syntax descriptions. I recommend reading the hackage page of "semi-iso" first, as it contains much more information.

Once you write a syntax description (polymorphic in the syntax category) you can instantiate it both as a parser or as a pretty-printer. The library "syntax-attoparsec" gives you the ability to extract an Attoparsec parser. Pretty-printing is implemented by the "syntax-printer" library, which uses Text and ByteString builders. (Note that formatting is handled by "syntax" itself, not by the printer library)

Advanced formatting and parsing (for example indentation, haskell layout rule) is implemented as category transformers (similar to monad transformers). Currently only simple indentation is implemented (in Data.Syntax.Indent) - basically a reader category transformer that tracks current indentation level. I plan on implementing Haskell layout rule in the future.

The library can work with both text and binary data. Alas, there are no binary combinators implemented yet.

EXAMPLES! See syntax-example and syntax-example-json for examples.

  • "syntax-example" implements a simple lambda calculus.

  • "syntax-example-json" implements a json parser and pretty printer.

Author
Paweł Nowak
Bug reports
n/a
Category
Data
Copyright
Paweł Nowak 2014
Homepage
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Maintainer
Paweł Nowak <pawel834@gmail.com>
Package URL
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Stability
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