diff --git a/src/app.ts b/src/app.ts
index 040a281..f35c761 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -138,7 +138,7 @@ function prase(expression: string, i: number, terminators: string[], args: strin
         escaped = true;
         break;
 
-      case "[": // RNG vyber
+      case "[": { // RNG vyber
         let option: string, term: string | undefined;
         const options: string[] = [];
 
@@ -151,8 +151,9 @@ function prase(expression: string, i: number, terminators: string[], args: strin
           ret += options[rand(options.length)];
 
         break;
+      }
 
-      case "<": // RNG cislo
+      case "<": {  // RNG cislo
         let min: string, max: string;
         [min, i] = prase(expression, i, [","], args);
         [max, i] = prase(expression, i, [">"], args);
@@ -166,8 +167,9 @@ function prase(expression: string, i: number, terminators: string[], args: strin
         ret += rand(imax - imin + 1) + imin;
 
         break;
+      }
 
-      case "{": // ARG
+      case "{": {// ARG
         let argId: string;
         [argId, i] = prase(expression, i, ["}"], args);
 
@@ -182,6 +184,7 @@ function prase(expression: string, i: number, terminators: string[], args: strin
         }
 
         break;
+      }
 
       default:
         for (const terminator of terminators) {