From 467210daee147508f1abfed52dcb82c28dd27f3f Mon Sep 17 00:00:00 2001
From: Sebastian Waschik <sebastian.waschik@gmx.de>
Date: Thu, 14 Dec 2023 11:49:50 +0100
Subject: [PATCH] Return a closure without arguments in gfind

---
 _glua-tests/issues.lua | 15 +++++++++++++++
 stringlib.go           | 10 +++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/_glua-tests/issues.lua b/_glua-tests/issues.lua
index 6d6343ab..460cf916 100644
--- a/_glua-tests/issues.lua
+++ b/_glua-tests/issues.lua
@@ -490,3 +490,18 @@ function test()
   assert(b == nil)
 end
 test()
+
+-- issue #462
+function test()
+  local x = string.gmatch("asdf", "a")
+  assert(x() == "a", "check gmatch callback")
+
+  local expected = {
+    "a",
+    "c",
+  }
+  for i in string.gmatch("abc", "[ac]") do
+    assert(i == table.remove(expected, 1), "check gmatch inside loop")
+  end
+end
+test()
diff --git a/stringlib.go b/stringlib.go
index f484c2b3..8ab8dc15 100644
--- a/stringlib.go
+++ b/stringlib.go
@@ -14,7 +14,7 @@ func OpenString(L *LState) int {
 	//_, ok := L.G.builtinMts[int(LTString)]
 	//if !ok {
 	mod = L.RegisterModule(StringLibName, strFuncs).(*LTable)
-	gmatch := L.NewClosure(strGmatch, L.NewFunction(strGmatchIter))
+	gmatch := L.NewFunction(strGmatch)
 	mod.RawSetString("gmatch", gmatch)
 	mod.RawSetString("gfind", gmatch)
 	mod.RawSetString("__index", mod)
@@ -299,7 +299,7 @@ type strMatchData struct {
 }
 
 func strGmatchIter(L *LState) int {
-	md := L.CheckUserData(1).Value.(*strMatchData)
+	md := L.CheckUserData(UpvalueIndex(1)).Value.(*strMatchData)
 	str := md.str
 	matches := md.matches
 	idx := md.pos
@@ -331,11 +331,11 @@ func strGmatch(L *LState) int {
 	if err != nil {
 		L.RaiseError(err.Error())
 	}
-	L.Push(L.Get(UpvalueIndex(1)))
 	ud := L.NewUserData()
 	ud.Value = &strMatchData{str, 0, mds}
-	L.Push(ud)
-	return 2
+	f := L.NewClosure(strGmatchIter, ud)
+	L.Push(f)
+	return 1
 }
 
 func strLen(L *LState) int {