From 68993a5ffb784a7648f886bb3221703aaaf000ce Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Sat, 9 Mar 2019 15:51:52 -0800
Subject: [PATCH] Added support for iteration over coroutines

---
 builtin_metatables.lua  | 36 ++++++++++++++++++++++++++++++------
 builtin_metatables.moon | 20 +++++++++++++++++---
 2 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/builtin_metatables.lua b/builtin_metatables.lua
index f659ad3..63d865c 100644
--- a/builtin_metatables.lua
+++ b/builtin_metatables.lua
@@ -1,9 +1,6 @@
 require("text")
 local number_mt = {
   __type = "a Number",
-  __len = function(self)
-    return self
-  end,
   as_lua = tostring,
   as_nomsu = tostring,
   as_text = tostring,
@@ -176,13 +173,40 @@ local fn_mt = {
 }
 fn_mt.__index = fn_mt
 debug.setmetatable((function() end), fn_mt)
-local co_mt = {
+local _last_co_i = setmetatable({ }, {
+  __mode = 'k'
+})
+local co_mt
+co_mt = {
   __type = "a Coroutine",
   as_text = function(self)
-    return (tostring(self):gsub("thread", "Coroutine"))
+    return (tostring(self):gsub("thread", "Coroutine")) .. " (" .. coroutine.status(self) .. ")"
+  end,
+  __len = function(self)
+    return math.huge
+  end,
+  __call = coroutine.resume,
+  __next = function(self, k)
+    local ok, val = coroutine.resume(self)
+    if ok then
+      return (k or 0) + 1, val
+    end
+  end,
+  __index = function(self, k)
+    if k == (_last_co_i[self] or 0) + 1 then
+      local ret = {
+        coroutine.resume(self, k)
+      }
+      _last_co_i[self] = k
+      if ret[1] then
+        return table.unpack(ret, 2)
+      else
+        return nil
+      end
+    end
+    return co_mt[k]
   end
 }
-co_mt.__index = co_mt
 debug.setmetatable(coroutine.create(function() end), co_mt)
 local nil_mt = {
   __type = "Nil",
diff --git a/builtin_metatables.moon b/builtin_metatables.moon
index ac8beff..7af5bf7 100644
--- a/builtin_metatables.moon
+++ b/builtin_metatables.moon
@@ -3,7 +3,6 @@ require "text"
 
 number_mt =
     __type: "a Number"
-    __len: => @
     as_lua: tostring
     as_nomsu: tostring
     as_text: tostring
@@ -74,10 +73,25 @@ fn_mt =
 fn_mt.__index = fn_mt
 debug.setmetatable (->), fn_mt
 
+_last_co_i = setmetatable({}, {__mode:'k'})
+local co_mt
 co_mt =
     __type: "a Coroutine"
-    as_text: => (tostring(@)\gsub("thread", "Coroutine"))
-co_mt.__index = co_mt
+    as_text: => (tostring(@)\gsub("thread", "Coroutine")).." ("..coroutine.status(@)..")"
+    __len: => math.huge
+    __call: coroutine.resume
+    __next: (k)=>
+        ok, val = coroutine.resume(@)
+        if ok then return (k or 0) + 1, val
+    __index: (k)=>
+        if k == (_last_co_i[@] or 0) + 1
+            ret = {coroutine.resume(@, k)}
+            _last_co_i[@] = k
+            if ret[1]
+                return table.unpack(ret, 2)
+            else
+                return nil
+        return co_mt[k]
 debug.setmetatable(coroutine.create(->), co_mt)
 
 nil_mt =