Needs documentation for the runtime JS shims in tessel/runtime

[paulcuth]

Hi,

I'm currently looking at using Colony outside of the Tessel ecosystem and I'm unable to output working Lua code.

For example, if we execute the following JavaScript in Node...

var fs = require('fs'),
    compiler = require('colony-compiler'),
    source = "function sum(a,b){return a+b;} module.exports = {sum:sum};";

fs.writeFile ('output.lua', compiler.colonize(source).source);

... it outputs the following Lua in output.lua (module wrapping omitted)...

local sum = sum;
sum = (function () local sum = nil; sum = function (this, a, b)
--[[18]] if true then return ((a)+(b)); end
end; sum.name = "sum"; return sum; end)();
--[[0]] 
--[[31]] module.exports = _obj({
  ["sum"]=sum
});

This fails to run in Lua 5.1, 5.2 and LuaJIT because it tries to add a name property to a function. It produces the following error:

lua: ./output.lua:10: attempt to index local 'sum' (a function value)

Is this expected behaviour? Am I using different versions of Lua than you? Do you have a custom build of Lua where adding properties to functions is allowed?

[kevinmehall]

The init code in the Tessel runtime modifies the Function metatable to simulate JavaScript semantics where everything is an object. Functions get a hidden table that holds properties that appear to be on the function.

https://github.com/tessel/runtime/blob/master/src/colony/lua/colony-init.lua#L280

You'll need the Lua in that directory to get a functioning JS environment.

[kevinmehall]

(I've edited the title for the actionable issue on this repository)