[anonymoushn]

The list comprehensions are really great. Most of the time when I'm writing Lua I can't be bothered to write exactly what Moonscript outputs for a list comprehension because it's noisy, but it's what I really would write if I cared about tiny amounts of performance.

[rweichler]

Idk. Still not sold. You can do list comprehensions in regular Lua with something like this:

    function listcomp(t, f)
        local r = {}
        for k,v in pairs(t) do
            r[k] = v
        end
        return r
    end

And then, your Lua code would be like:

    listcomp({1, 2, 3, 4}, function(k, v)
        return v*2
    end)

Which would be the equivalent to this in MoonScript:

    [v*2 for k,v in pairs({1, 2, 3 ,4})]

I dunno. Just seems like a wash to me. And then you think about the extra compile step to run MoonScript, and the potential performance hits, and I'm just turned off completely from it.

[shalabhc]

There are no potential performance hits. In particular the code generated for list comprehensions would be faster than your example because there is no extra function call per item.

[anonymoushn]

Over here it generated

  local b
  do
    local _accum_0 = { }
    local _len_0 = 1
    for k, v in pairs({
      1,
      2,
      3,
      4
    }) do
      _accum_0[_len_0] = v * 2
      _len_0 = _len_0 + 1
    end
    b = _accum_0
  end

It did a pretty good job. Unlike your code, it doesn't have any function calls, and unlike the code I would probably write, it doesn't use the # operator.