blocking-with-coros.lua

local coroutine = require('coroutine')
local table = require('table')
local uv = require("luv")

local function await(fn, ...)
  local co = coroutine.running()
  local args = {...}
  table.insert(args, function (err, result)
    if err then error(err) end
    return assert(coroutine.resume(co, result))
  end)
  fn(unpack(args))
  return coroutine.yield()
end

coroutine.wrap(function ()
  local fd = await(uv.fs_open, uv.execpath(), "r", tonumber("644", 8))
  local stat = await(uv.fs_fstat, fd)
  local chunk = await(uv.fs_read, fd, 1000, stat.size-1000)
  p{
    fd=fd,
    stat=stat,
    chunk=chunk
  }
end)()