Create some subroutines and test

src/game/rule/operation/convert.go

@@ -0,0 +1,22 @@
+package operation
+
+import (
+	"fmt"
+	"strconv"
+)
+
+func convertNumber(v interface{}) int {
+	s := fmt.Sprint(v)
+	v2, _ := strconv.ParseFloat(s, 64)
+	return int(v2)
+}
+
+func convertString(v interface{}) string {
+	switch v.(type) {
+	case string:
+		return v.(string)
+	case []byte:
+		return string(v.([]byte))
+	}
+	return fmt.Sprint(v)
+}