improve luna.utf methods

1 files changed, 5 insertions, 2 deletions

diff --git a/main.go b/main.go
index dd5e7fe..7ee2c9d 100644
--- a/main.go
+++ b/main.go
@@ -10,6 +10,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"unicode/utf8"
 	"runtime"
 	"runtime/cgo"
 	"strings"
@@ -348,7 +349,7 @@ func main() {
 		if err != nil {
 			return luaErr(l, err)
 		}
-		return luaOk(l, len(str))
+		return luaOk(l, utf8.RuneCountInString(str))
 	}
 	utfModule["lower"] = func (l *Lua) int {
 		var str string
@@ -365,7 +366,9 @@ func main() {
 		if err != nil {
 			return luaErr(l, err)
 		}
-		return luaOk(l, str[start-1:start-1+length])
+		runes := []rune(str)
+		cut := runes[start-1:start-1+length]
+		return luaOk(l, string(cut))
 	}
 
 	module := make(map[string]any)