klä

An LFE Wrapper Library used to Dress Up Erlang Libraries in a Lispy Costume

Table of Contents

• Introduction
• Dependencies
• Installation
• Usage

Introduction ↟

This is a utility library created and used simply for aesthetics.

Dependencies ↟

As of version 0.5.0, this project assumes that you have rebar3 installed somwhere in your $PATH. It no longer uses the old version of rebar. If you do not wish to use rebar3, you may use the most recent rebar2-compatible release of kla: 0.4.2.

Installation ↟

Just add it to your rebar.config deps:

{deps, [
    ...
    {kla, "0.9.1"}
]}.

And then do the usual:

    $ rebar compile

Usage ↟

To use this library, one does the following (usually in an include file):

1. Create a function that returns a list of function names as they would be called in an LFE application.
2. Create a generator function that will convert these to Erlang names and then look them up in the specified Erlang module.
3. Call the generate function in the include.
4. Use the include in your application.

The moneta project makes heavy use of kla; here's an excerpt of the "query" include file:

(eval-when-compile
  (defun get-api-funcs ()
    '((append 1) (append 2)
      (cursor 1) (cursor 2)
      (delete-cursor 1)
      (eval 1) (eval 2)
      (e 1) (e 2)
      (fold 3) (fold 4)
      (format-error 1)
      (info 1) (info 2)
      (keysort 2) (keysort 3)
      (next-answers 1) (next-answers 2)
      (q 1) (q 2)
      (sort 1) (sort 2)
      (string-to-handle 1) (string-to-handle 2) (string-to-handle 3)
      (table 2))))

(defmacro generate-api ()
  `(progn ,@(kla:make-funcs (get-api-funcs) 'qlc)))

(generate-api)

Then, in the library source file mnt-qry:

(defmodule mnt-qry
  (export all))

(include-lib "moneta/include/mnt-qry.lfe")

at which point all the functions listed in get-api-funcs are now available for use in mnt-qry. Calling the Lisp-style functions in mnt-qry will result in calls to the under-score functions in the Erlang qlc library.