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Neotomex

Obligatory Alpha Quality Disclaimer

A PEG implementation with an Elixir interface.

While inspired by neotoma, Neotomex doesn't use functional composition. Instead, it creates a data structure representing a grammar, and then applies the data structure to an input.

NB: For now, Neotomex is a recursive rather than packrat parser.

Usage

By taking advantage of pattern matching and Elixir's macros, Neotomex provides a fresh DSL for specifying grammars.

Here's a simple grammar for parsing a number:

defmodule Number do
  use Neotomex.ExGrammar

  @root true
  define :number, "digit+" do
    digits -> digits |> Enum.join |> String.to_integer
  end

  define :digit, "[0-9]"
end

42 = Number.parse! "42"

See the /examples directory for other examples, including a json grammar.

Learning More

Check out the module docs to learn more about how Neotomex specifies grammars, and how to write your own:

iex> h Neotomex.Grammar
iex> h Neotomex.ExGrammar

Look in examples/ for existing usage.

Roadmap

Packrat parsing
Match labels a la neotoma (e.g. a:match)