9 files changed, 203 insertions(+), 0 deletions(-)

A .formatter.exs
A .gitignore
A README.md
A lib/lixp.ex
A lib/lixp/parser.ex
A mix.exs
A mix.lock
A test/lixp_test.exs
A test/test_helper.exs

@@ 0,0 1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

@@ 0,0 1,27 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+lixp-*.tar
+
+
+# Temporary files for e.g. tests
+/tmp

@@ 0,0 1,21 @@
+# Lixp
+
+**TODO: Add description**
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `lixp` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:lixp, "~> 0.1.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at [https://hexdocs.pm/lixp](https://hexdocs.pm/lixp).
+

@@ 0,0 1,36 @@
+defmodule Lixp do
+  def eval(str) do
+    {:ok, [res], _, _, _, _} = Lixp.Parser.program(str)
+    eval(res, %{})
+  end
+  defp eval(num, _env) when is_number(num) do
+    num
+  end
+  defp eval(atom, _env) when is_atom(atom) do
+    atom
+  end
+  defp eval({:symbol, sym}, env) do
+    env[sym]
+  end
+  defp eval([{:symbol, "lambda"} | rest ], env) do
+    [ arg_names | [body] ] = rest
+    fn args ->
+      arg_names = Enum.map(arg_names, fn {:symbol, name} -> name end)
+      combination = Enum.zip(arg_names, args)
+      eval(body, extend(combination, env))
+    end
+  end
+  defp eval([h | t], env) do
+    f = eval(h, env)
+    args = Enum.map(t, &eval(&1, env))
+  
+    f.(args)
+  end
+  defp extend([{name, val} | rest], env) do
+    extend(rest, Map.put(env, name, val))
+  end
+  
+  defp extend([], env) do
+    env
+  end
+end

@@ 0,0 1,74 @@
+defmodule Lixp.Parser.Help do
+  import NimbleParsec
+  def digit do
+    ascii_char([?0..?9]) |> map(:char_to_string)
+  end
+  def dot do
+    ascii_char([?.]) |> map(:char_to_string)
+  end
+  def number do
+    digit()
+    |> optional(repeat(digit()))
+    |> optional(dot())
+    |> optional(repeat(digit()))
+    |> reduce({Enum, :join, [""]})
+    |> map(:parse_float)
+    |> label("number")
+  end
+end
+defmodule Lixp.Parser do
+  import NimbleParsec
+  import Lixp.Parser.Help
+  def parse_float(str) do
+    {n, _} = Float.parse(str)
+    n
+  end
+  def char_to_string(char) do
+    List.to_string([char])
+  end
+  colon = string(":")
+  valid_atom_chars = ascii_string([?^..?z, ?!..?', ?*..?., ?0..?Z], min: 1)
+  
+  atom =
+    ignore(colon)
+    |> concat(valid_atom_chars)
+    |> map({String, :to_atom, []})
+    |> label("atom")
+  
+  def wrap_symbol(sym) do
+    {:symbol, sym}
+  end
+  
+  symbol =
+    valid_atom_chars
+    |> map({:wrap_symbol, []})
+    |> label("symbol")
+  open_list = ascii_char([?(]) |> map(:char_to_string)
+  close_list = ascii_char([?)]) |> map(:char_to_string)
+  
+  list =
+    ignore(open_list)
+    |> optional(repeat(choice([
+            atom,
+            number(),
+            parsec(:list),
+            symbol,
+            ignore(string(" "))])))
+    |> concat(ignore(close_list))
+    |> reduce({Enum, :into, [[]]})
+    |> label("list")
+  
+    defparsec(
+      :list,
+      list
+    )
+  defparsec(
+    :term,
+    choice([list, number(), atom, symbol, ignore(string(" "))])
+  )
+  
+  defparsec(
+    :program,
+    repeat(parsec(:term))
+  )
+end

@@ 0,0 1,29 @@
+defmodule Lixp.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :lixp,
+      version: "0.1.0",
+      elixir: "~> 1.11",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+      {:nimble_parsec, "~> 1.0"}
+    ]
+  end
+end

@@ 0,0 1,3 @@
+%{
+  "nimble_parsec": {:hex, :nimble_parsec, "1.1.0", "3a6fca1550363552e54c216debb6a9e95bd8d32348938e13de5eda962c0d7f89", [:mix], [], "hexpm", "08eb32d66b706e913ff748f11694b17981c0b04a33ef470e33e11b3d3ac8f54b"},
+}

@@ 0,0 1,8 @@
+defmodule LixpTest do
+  use ExUnit.Case
+  doctest Lixp
+
+  test "greets the world" do
+    assert Lixp.hello() == :world
+  end
+end

@@ 0,0 1,1 @@
+ExUnit.start()