* lfedn – edn ↔ lfe
#+BEGIN_SRC conf :tangle .gitignore :exports none
# -*- conf -*-
.rebar3
_*
.eunit
,*.o
,*.beam
,*.plt
,*.swp
,*.swo
.erlang.cookie
ebin
log
erl_crash.dump
.rebar
_rel
_deps
_plugins
_tdeps
logs
_build
rebar.lock
.DS_Store

src/erldn_lexer.erl
src/erldn_parser.erl
#+END_SRC

#+BEGIN_SRC conf :tangle .gitmodules :exports none
# -*- conf -*-
[submodule "doc"]
path   = doc
url    = git@github.com:quasiquoting/lfedn.git
branch = gh-pages
#+END_SRC

#+BEGIN_SRC yaml :tangle .travis.yml :exports none
language: erlang
# http://stackoverflow.com/a/24600210/1793234
# Handle git submodules yourself
git:
  submodules: false
# Use sed to replace the SSH URL with the public URL, then initialize submodules
# Apply the replacement to rebar.config as well.
before_install:
  - sed -i 's/git@github.com[:\/]/https:\/\/github.com\//' .gitmodules rebar.config
  - git submodule update --init --recursive
install: true
before_script:
    - wget https://s3.amazonaws.com/rebar3/rebar3
    - chmod 755 rebar3
script:
  - ./rebar3 eunit
notifications:
  recipients:
    - quasiquoting@gmail.com
otp_release:
  - 18.1
  - 18.0
#+END_SRC

[[https://travis-ci.org/quasiquoting/lfedn][file:https://travis-ci.org/quasiquoting/lfedn.svg?branch=develop]]

=lfedn= is a parser for the [[https://github.com/edn-format/edn][edn specification]], implemented using [[http://www.erlang.org/doc/man/leex.html][leex]] and [[http://www.erlang.org/doc/man/yecc.html][yecc]]
and tested with [[http://www.erlang.org/doc/man/eunit.html][eunit]].

This is a low-level parser from edn to LFE data structures. You have to decide
on how, specifically, to represent them, since each user may have a different
need. There is no imposition here.

** Dependencies
   :PROPERTIES:
   :tangle:   rebar.config
   :END:
#+BEGIN_SRC erlang :exports none
{eunit_compile_opts,
 [{src_dirs, ["src", "test"]}]}.

{provider_hooks,
 [{pre, [{compile, {lfe, compile}}]}]}.
#+END_SRC

This project assumes you have [[http://www.rebar3.org][rebar3]] installed somwhere in your ~$PATH~.

This project depends upon the follow, which are installed to the
~_build/default/lib~ directory of this project when you run ~rebar3 compile~.

- [[https://github.com/rvirding/lfe][LFE]] (Lisp Flavored Erlang; needed only to compile)
  #+BEGIN_SRC erlang
{deps,
 [{lfe,
   {git, "git@github.com/rvirding/lfe.git",
    {tag, "0.10.1"}}},
  #+END_SRC
- [[https://github.com/lfex/ltest][ltest]] (needed only to run the tests)
  #+BEGIN_SRC erlang :padline no
  {ltest,
   {git, "git@github.com/lfex/ltest.git",
    {tag, "0.7.0"}}}]}.
  #+END_SRC

** Installation
Just add it to your =rebar.config= [[https://www.rebar3.org/docs/dependencies][deps]]:
#+BEGIN_SRC erlang
{deps,
 [% ...
  {lfedn,
   {git, "git@github.com:quasiquoting/lfedn.git",
    {tag, "1.2.0"}}}]}.
#+END_SRC
** Build
#+BEGIN_SRC sh
$ rebar3 compile
#+END_SRC

** Test
#+BEGIN_SRC sh
$ rebar3 eunit -v
#+END_SRC

** Examples
☛ [[file:EXAMPLES.org][EXAMPLES.org]]
** API
☛ [[http://quasiquoting.org/lfedn][Documentation]]

** Type Mappings
| edn            | LFE                                          |
|----------------+----------------------------------------------|
| boolean        | boolean                                      |
| char           | string                                       |
| float          | float                                        |
| integer        | integer                                      |
| keyword¹       | atom                                         |
| list           | list                                         |
| map            | tagged list ⇒ ~`#(map [#(,key1 ,val1) ...])~ |
| ~nil~ (symbol) | ~nil~ (atom)                                 |
| set²           | tagged list ⇒ ~#(set [...])~                 |
| string         | binary string (utf-8)                        |
| symbol         | atom                                         |
| tagged literal | tagged tuple ⇒ ~`#(tag ,symbol ,value)~      |
| vector         | tagged list ⇒ ~#(vector [...])~              |

¹: Although keyword ↦ atom, ~:nil~ ↦ ~#(keyword nil)~.

²: Uniqueness is not checked at parse time.

** To LFE Mappings
The ~to-lfe~ function transforms incoming data structures to be more
LFE-friendly, but the results can't be converted back to string without
transforming again. The default mappings are:

| edn            | LFE                                                  |
|----------------+------------------------------------------------------|
| boolean        | boolean                                              |
| char           | string                                               |
| float          | float                                                |
| integer        | integer                                              |
| keyword        | atom                                                 |
| list           | list                                                 |
| map            | [[http://www.erlang.org/doc/man/dict.html][dict]]                                                 |
| ~nil~ (symbol) | ~nil~ (atom)                                         |
| set            | [[http://www.erlang.org/doc/man/sets.html][set]]                                                  |
| string         | binary string                                        |
| symbol         | atom                                                 |
| tagged literal | call registered handler for tag or fail if not found |
| vector         | list                                                 |

** Authors
| Mariano Guerra ([[https://github.com/marianoguerra][@marianoguerra]]) | [[https://github.com/marianoguerra/erldn][erldn]] (Erlang) |
| Eric Bailey ([[https://github.com/yurrriq][@yurrriq]])          | [[https://github.com/quasiquoting/lfedn][lfedn]] (LFE)    |

** [[file:LICENSE][License]]
#+BEGIN_SRC txt :tangle LICENSE
The MIT License (MIT)

Copyright (c) 2013 Mariano Guerra
Copyright (c) 2015 Eric Bailey

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
#+END_SRC