@hackage syntax0.2.1.0

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

The interface is based on a custom Functor/Applicative/Monad hierarchy, provided by the 'semi-iso' package. You fmap using a semi-isomorphism instead of function. A semi-isomorphism is a isomorphism that can fail in both directions, with slightly weakened laws. It is worth to note that Isos and Prisms from lens are valid semi-isomorphisms :)

Once you write a description you can, for example turn it into an Attoparsec parser.

See syntax-example for an example, 'syntax-attoparsec' and 'syntax-pretty' for a parser/printer implementation.

The library was inspired by:

• Rendel, Tillmann, and Klaus Ostermann. "Invertible syntax descriptions: unifying parsing and pretty printing." ACM Sigplan Notices. Vol. 45. No. 11. ACM, 2010.

TODO:

• a printer library based on Text/ByteString builders (wrapping pretty is inefficient and doesn't use any features of it),

• try to implement indentation and Haskell layout rule,

• combinators for binary data formats, vectors,

• implementation of do notation for SemiIsoMonad with QuasiQuoters.