c/lua:coroutine continuation

c/lua/_demo/crroutine-continue/corroutine.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/lua"
+)
+
+func countdownContinue(L *lua.State, status c.Int, ctx lua.KContext) c.Int {
+	return countdown(L)
+}
+
+func countdown(L *lua.State) c.Int {
+	arg := L.Tointeger(lua.Upvalueindex(1))
+	c.Printf(c.Str("resume called with %d\n"), arg)
+	if arg > 0 {
+		L.Pushinteger(arg - 1)
+		L.Replace(lua.Upvalueindex(1))
+		L.Pushinteger(arg)
+		return L.Yieldk(1, c.Pointer(uintptr(0)), countdownContinue)
+	}
+	return 0
+}
+
+func createCountdown(L *lua.State) c.Int {
+	max := L.Checkinteger(1)
+	L.Pushinteger(max)
+	L.Pushcclosure(countdown, 1)
+	return 1
+}
+
+func main() {
+	L := lua.Newstate()
+	L.Openlibs()
+	defer L.Close()
+	L.Register(c.Str("create_countdown"), createCountdown)
+
+	testcode := c.Str(`
+ local countdown = create_countdown(5)
+ local co = coroutine.create(countdown)
+ while true do
+     local success, value = coroutine.resume(co)
+     if not success then
+         print('Error:', value)
+         break
+     end
+     if value == nil then break end
+     print('Lua received:', value)
+ end
+ print('Countdown finished');
+	`)
+
+	if L.Dostring(testcode) != lua.OK {
+		c.Printf(c.Str("Error: %s\n"), L.Tostring(-1))
+	}
+
+	L.Openlibs()
+}
+
+/* Expected output:
+resume called with 5
+Lua received:   5
+resume called with 4
+Lua received:   4
+resume called with 3
+Lua received:   3
+resume called with 2
+Lua received:   2
+resume called with 1
+Lua received:   1
+resume called with 0
+Countdown finished
+*/