About

The purpose of this project is just to compare few scripting engines for Erlang.

The goal is to answer next questions:

1. How much memory is needed for each engine?
2. How many concurrent instances of engine can be run?
3. How easy to use is each engine?

erlv8

Repo: https://github.com/beamjs/erlv8 About: V8 Integration with Erlang. Implemented in same way as erlang_js - linked-in driver

Answers:

1. How much memory: 10 loaded scripts consumed 6700M of virtual memory 20 loaded scripts consumed 12GB of virtual memory

2. How many concurrent instances: 100 with default settings

3. How easy: Very easy for simple cases

erlang_js

Repo: https://github.com/basho/erlang_js About: "erlang_js is a linked-in driver, API, and OTP application that embeds Mozilla’s Spidermonkey Javascript Virtual Machine in Erlang."

Note: to build http://lists.basho.com/pipermail/riak-users_lists.basho.com/2010-February/000436.html may be useful

Answers:

1. How much memory: Seems does not do pre-allocation. 400 instaces consumed about 150M of virtual memory

2. How many concurrent instances: As much as erlang VM allows

3. How easy: There are lack of documentation, but it is quite easy to find examples.

luerl

Repo: https://github.com/rvirding/luerl/ About: Lua interpreter written in Erlang

Answers:

1. How much memory: 1000 loaded scripts consumed about 2Mb of virtual memory.

2. How many concurrent instances: As much as erlang VM allows.

3. How easy: Suitable only for cases when result is needed (like some calculations). To make lua script interact with outer world - changes are needed in luerl

erl-lua

Repo: https://github.com/raycmorgan/erl-lua About: yet another Lua integration. At this time erl-lua is more like erlv8 - part of source is in c

Because erl-lua seems not maintained, I've used fork https://github.com/Motiejus/erl-lua wich seems more alive.

Note: to build erlualib you need lua been install + libluabind-dev (c++ bindings)

One more interesting thing: it is planned to use Lua for implementing gen_* behaviours (http://m.jakstys.lt/tech/2012/06/erlang-behaviours-in-lua/)

Answers:

1. How much memory: 1000 loaded scripts consumed about 5Mb of virtual memory.
2. How many concurrent instances: As much as erlang VM allows.
3. How easy: Not usable, currently.

erl-lua is just driver for lualib.