Luma

WARNING : Still a toy, still pretty buggy and unfinished

Luma is a lisp that compiles to Lua source code. It derives inspiration from the Scheme and Clojure families, and uses a combination of standard library and policy design to encourage a more repl-friendly, functional style of coding.

Luma is written entirely in Lua, depends only on Lua modules except for LPEG, and can be used in most places where Lua is already used.

Luma is known to work with Lua 5.1 and 5.2 as well as LuaJIT. Please note that version specific features like for example setfenv() in 5.1 and native integers in 5.3 do bubble up into Luma code, so it is important to keep track of what language you target.

TODO

• a reload-safe, require()-compatible module system
• line numbers in tracebacks
• Introspectable docstrings
• a better repl
• better macros, most likely hygienic
• more datastructures
• scheme compat mode?

Examples

Luma syntax is roughly Schemelike, without adhering to any standard:

;; My function foo
(define (foo a)
  (+ a 3))
(assert (= (foo 3) 6)

Luma has access to the full power of the Lua VM, including first class closures, tail call elimination, and coroutines:

(define (fib n)
  (define (loop a b n)
    (if (= n 0)
      a
      (loop b (+ a b) (- n 1)))))

(define (fib-iter)
  (define (loop a b)
    (coroutine.yield a)
    (loop b (+ a b)))
  (loop 1 1))

Normal Lua modules and tables behave as they do in Lua:

(define t (table "foo" "bar" "bar" "baz"))
(assert (= t.bar (get t "bar")))
(define a (array 4 3 2 1))
(assert (= (get a 1) 4)) ; index by 1, sorry~

...Although Luma introduces new datatypes and functions in its standard library, mostly built on the excellent luafun:

(define nums (map (partial + 1) (list 1 2 3 4)))
(assert (= (nth 2 nums) 3)) ; Still indexed by 1
(define scores (alist :player-1 -1 :player-2 1))
(define winning (filter (lambda (pair) (> (cdr pair) 0)) scores))
(define top-10
  (take 10 (sort scores (lambda (a b) (> (cdr a) (cdr b))))))

Installing

Luma uses Luarocks for dependency management and installation.

Run

# luarocks install luma

or

$ luarocks make

to install a copy.

Tests

Tests are written using the Busted framework. Get it from luarocks using:

# luarocks install busted

and run the tests using:

$ busted

License

Copyright (c) 2015 Kyle McLamb, under the MIT License.

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.