Lol — Lisp On erLang

Lol — and programming is fun again.

Why?

Because the world strongly needs another programming language.

A little bit more seriously: the main idea is to make metaprogramming in erlang easier.
It is not about replacing Erlang, it is about using the two together.

Why not LFE? Lol has:

• Lisp-1
• Small and clean codebase (for now :))

Why not Joxa?

• Joxa is not developed anymore and it uses code generation for the erlang core.

Build

$ git clone git://github.com/b0oh/lol.git
$ cd lol
$ ./rebar compile
$ echo '(defn hello [name] (io:format "Hello, ~s.~n" [name]))' > simple.lol
$ erl -pa ebin

1> lol_compiler:file("simple.lol", "ebin/simple.beam").
{ok,simple,[]}
2> simple:hello("Dima").
Hello, Dima.
ok

Example

Lol application example

Lol language

Forms

• Integer: 1
• Float: 1.1
• Symbol: symbol
• Simple string: "string"
• S-expr: ()

Special forms

• List: [1 2 3] expanding to (list 1 2 3)
• Tuple: {1 2 3} expanding to (tuple 1 2 3)
• Quote: '(1 2 3) expanding to (quote (1 2 3))
• Define public function:

(defn public [arg1 arg2]
  (expr1)
  (expr2))

• Define private function:

(defn- private [arg1 arg2]
  (expr1)
  (expr2))

• Lambda:

(fn [arg1 arg2] (expr1) (expr2))

• Let with pattern matching:

(let [{'ok file} (file:read_file "number")
      number (binary_to_integer file)]
  (io:format "Number is: ~p~n" [number]))

• Let with sequence in body:

(let [{'ok file} (file:read_file "number")
      number (binary_to_integer file)]
  (do
    (file:write_file "number_copy" (integer_to_binary number))
    (io:format "Number is: ~p~n" [number])))

• Case:

(case (get_coords)
  ({x y} 'ok)
  ({x y z} (do (first_expr) (second_expr))))

• Call:

(call 'func)
(call 'func [arg1 arg2])
(call 'mod 'func)
(call 'mod 'func [arg1 arg2])

• Apply:

(func)
(mod:func)
((fn [x] x) "some")

Plans

• Full erlang forms support: float, binary, characters, strings with interpolation, records, maps, etc
• Full erlang syntax support: receive, clauses for functions and lambdas, etc
• Improve lol forms support: let, do, def, etc
• Extended importing and name aliasing
• Macroses
• deftransform form for providing macroses for Erlang from Lol
• Translation right in Erlang sources
• stdlib
• Write Lol on Lol

It is dedicated to “Let Over Lambda” and “Land of Lisp”.

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Have fun.