define utf lua module for utf-operations on strings

1 files changed, 25 insertions, 0 deletions

diff --git a/main.go b/main.go
index 3f75109..993c7bb 100644
--- a/main.go
+++ b/main.go
@@ -380,10 +380,35 @@ func main() {
 		return 0
 	}
 
+	// define luna.utf module
+	utfModule := make(map[string]any)
+	utfModule["lower"] = func (l *Lua) int {
+		var str string
+		err := l.Scan(&str)
+		if err != nil {
+			// FIXME: handle.
+			return 0
+		}
+		l.PushString(strings.ToLower(str))
+		return 1
+	}
+	utfModule["sub"] = func (l *Lua) int {
+		var str string
+		var start, length int
+		err := l.Scan(&str, &start, &length)
+		if err != nil {
+			// FIXME: handle.
+			return 0
+		}
+		l.PushString(str[start-1:length])
+		return 1
+	}
+
 	module := make(map[string]any)
 	module["router"] = routeModule
 	module["http"] = httpModule
 	module["db"] = dbModule
+	module["utf"] = utfModule
 
 	wg := sync.WaitGroup{}
 	wg.Add(*wrksNum)