Remove coroutine wrappers from iterators

libs/iterables/ArrayIterable.lua

@@ -5,8 +5,6 @@ the order may change if the internal array is modified. Some versions may use a
 map function to shape the objects before they are accessed.
 ]=]
 
-local wrap, yield = coroutine.wrap, coroutine.yield
-
 local Iterable = require('iterables/Iterable')
 
 local ArrayIterable, get = require('class')('ArrayIterable', Iterable)
@@ -83,14 +81,20 @@ function ArrayIterable:iter()
 	end
 	local map = self._map
 	if map then
-		return wrap(function()
-			for _, v in ipairs(array) do
-				local obj = map(v)
-				if obj then
-					yield(obj)
+		local i = 0
+		return function()
+			while true do
+				i = i + 1
+				local v = array[i]
+				if not v then
+					return nil
+				end
+				v = map(array[i])
+				if v then
+					return v
 				end
 			end
-		end)
+		end
 	else
 		local i = 0
 		return function()

libs/iterables/Iterable.lua

@@ -9,7 +9,6 @@ all stored objects should have a `__hash` method.
 ]=]
 
 local random = math.random
-local wrap, yield = coroutine.wrap, coroutine.yield
 local insert, sort, pack = table.insert, table.sort, table.pack
 
 local Iterable = require('class')('Iterable')
@@ -21,11 +20,14 @@ local Iterable = require('class')('Iterable')
 a `key, value` pair, where `key` is the result of calling `__hash` on the `value`.
 ]=]
 function Iterable:__pairs()
-	return wrap(function()
-		for obj in self:iter() do
-			yield(obj:__hash(), obj)
+	local gen = self:iter()
+	return function()
+		local obj = gen()
+		if not obj then
+			return nil
 		end
-	end)
+		return obj:__hash(), obj
+	end
 end
 
 --[=[
@@ -80,13 +82,18 @@ end
 @d Returns an iterator that returns all objects that satisfy a predicate.
 ]=]
 function Iterable:findAll(fn)
-	return wrap(function()
-		for obj in self:iter() do
+	local gen = self:iter()
+	return function()
+		while true do
+			local obj = gen()
+			if not obj then
+				return nil
+			end
 			if fn(obj) then
-				yield(obj)
+				return obj
 			end
 		end
-	end)
+	end
 end
 
 --[=[
@@ -249,19 +256,22 @@ function Iterable:pick(...)
 	local keys = pack(...)
 	local values = {}
 	local n = keys.n
-	return wrap(function()
-		for obj in self:iter() do
-			for i = 1, n do
-				local k = keys[i]
-				if type(k) == 'function' then
-					values[i] = k(obj)
-				else
-					values[i] = obj[k]
-				end
+	local gen = self:iter()
+	return function()
+		local obj = gen()
+		if not obj then
+			return nil
+		end
+		for i = 1, n do
+			local k = keys[i]
+			if type(k) == 'function' then
+				values[i] = k(obj)
+			else
+				values[i] = obj[k]
 			end
-			yield(unpack(values, 1, n))
 		end
-	end)
+		return unpack(values, 1, n)
+	end
 end
 
 return Iterable

libs/iterables/TableIterable.lua

@@ -4,8 +4,6 @@
 Some versions may use a map function to shape the objects before they are accessed.
 ]=]
 
-local wrap, yield = coroutine.wrap, coroutine.yield
-
 local Iterable = require('iterables/Iterable')
 
 local TableIterable = require('class')('TableIterable', Iterable)
@@ -29,14 +27,19 @@ function TableIterable:iter()
 	end
 	local map = self._map
 	if map then
-		return wrap(function()
-			for _, v in pairs(tbl) do
-				local obj = map(v)
-				if obj then
-					yield(obj)
+		local k, v
+		return function()
+			while true do
+				k, v = next(tbl, k)
+				if not v then
+					return nil
+				end
+				v = map(v)
+				if v then
+					return v
 				end
 			end
-		end)
+		end
 	else
 		local k, v
 		return function()

libs/utils/Emitter.lua

@@ -127,13 +127,15 @@ end
 function Emitter:getListeners(name)
 	local listeners = self._listeners[name]
 	if not listeners then return function() end end
-	return wrap(function()
-		for _, listener in ipairs(listeners) do
-			if listener then
-				yield(listener.fn)
+	local i = 0
+	return function()
+		while i < #listeners do
+			i = i + 1
+			if listeners[i] then
+				return listeners[i].fn
 			end
 		end
-	end)
+	end
 end
 
 --[=[