README.md

TyRE

Dependently-typed regex parser in Idris 2.

We assign each regex pattern a shape which denotes the type of the of the output parse tree, e.g. "[a-c]*" has type List Char. We guarantee result type correctness with dependent-type verification. On top of the parser we add Radanne's type-indexed combinators (tyre).

Usage

To use TyRE add needed dependencies to your .ipkg file. (Please note: the order of dependencies matters - contrib needs to be after tyre.)

depends = tyre, contrib

Now just import Data.Regex, which cointains the following functions for parsing and matching:

getToken : TyRE a -> Stream Char -> (Maybe a, Stream Char)
match : TyRE a -> String -> Bool
parse : TyRE a -> String -> Maybe a

Example

Parsing time (from tests/tyre/time-full):

import Data.Regex

digit : Char -> Integer
digit c = cast c - cast '0'

Time : TyRE (Integer, Integer)
Time = (f . fromEither `map` r "([01][0-9])!|([2][0-4])!")
        <*>  (f `map` r ":([0-5][0-9])!") where
          f : (Char, Char) -> Integer
          f (x, y) = (10 * digit x + digit y)

Idris 2 Parser

The module Text/* is a copy of Idris 2 Text/* module from contib package with slight modifications -- dropped PrettyPrint, added public export annotations, fastunpack switched to unpack. We made this copy to Idris 2's type checker to fully reduce terms.