--- a/hglib.lua	Mon Oct 17 23:27:50 2016 +0800
+++ b/hglib.lua	Sun Oct 23 17:53:32 2016 +0800
@@ -128,13 +128,32 @@
 	end
 end
 
-function Client:runcommand(command, input)
+function Client:runcommand_co(command)
 	if not self.capabilities.runcommand then
-		return nil, '', 'runcommand is not supported by this command server', ''
+		return nil, 'runcommand is not supported by this command server'
 	end
 	self.wh:write('runcommand\n')
 	write_block(self.wh, unpack(command))
 	self.wh:flush()
+	return coroutine.create(function()
+		while true do
+			local channel, message = read_channel(self.rh)
+			if channel == 'r' then
+				return channel, decode_i4(message)
+			elseif channel:lower() ~= channel and channel ~= 'I' and channel ~= 'L' then
+				return channel, message
+			else
+				coroutine.yield(channel, message)
+			end
+		end
+	end)
+end
+
+function Client:runcommand(command, input)
+	local co, err = self:runcommand_co(command)
+	if type(co) ~= 'thread' then
+		return nil, '', err, ''
+	end
 	local o = ''
 	local e = ''
 	local d = ''
@@ -143,10 +162,13 @@
 		self.wh:flush()
 		input = input:sub(length + 1)
 	end
-	while true do
-		local channel, message = read_channel(self.rh)
+	while coroutine.status(co) ~= 'dead' do
+		local status, channel, message = coroutine.resume(co)
+		if not status then
+			return nil, '', '\nhglib: coroutine failure: ' .. channel, ''
+		end
 		if channel == 'r' then
-			return decode_i4(message), o, e, d
+			return message, o, e, d
 		elseif channel == 'o' then
 			o = o .. message
 		elseif channel == 'e' then