Elm Edn Parser

A library for parsing extensible data notation, "Edn" in Elm!

This is very useful for communicating between Clojure and Elm.

This is just for parsing edn data into a Edn elm type. For full decoding check out edn-decode

The "Edn" Type

type Edn
    = EdnString String
    | EdnSymbol String
    -- keywords are represented as strings with optional namespace
    | EdnKeyword (Maybe String) String
    | EdnList (List Edn)
    | EdnVector (Array Edn)
    -- maps in Edn can have keys that are not strings, so we represent them as a list
    -- of tuples here, leaving the translation to a map up to decoders
    | EdnMap (List ( Edn, Edn ))
    -- sets must consist of predefined comparables in Elm, so it's represented
    -- as a list on this type, leaving the translation to a set up to decoders
    | EdnSet (List Edn)
    | EdnNil
    | EdnBool Bool
    | EdnInt Int
    | EdnFloat Float
    | EdnChar Char
    -- user defined tags have a namespace and a name, followed by a nested edn value
    | EdnTag String String Edn
    | EdnSymbol String

Usage

import Edn exposing (Edn)
import Edn.Parser exposing (Error)

result : Result Error Edn
result = Edn.Parser.run """(1 true {:hello "world"})""" 

Decoding/Encoding

This library doesn't provide Encoders and Decoders for the types in the Edn module.

Extensible Data Notation has a few interesting types that don't necessarily translate cleanly to Elm without making some decisions about how that transform happens.

For full decoding check out edn-decoder or any other library that implements decoders for the Edn type.

Prior Art

The tests in this library and the escaped unicode parsing are largely drawn from Robert Vollmert's excellent elm-edn library.