Fix If

BauSystem_Main/src/de/steamwar/bausystem/features/script/command/If.java

@@ -40,6 +40,16 @@ public class If implements SpecialCommand {
             return true;
         }
 
+        if (command[2].equals("exists")) {
+            if (scriptExecutor.isVariable(command[1])) {
+                setIndex(scriptExecutor, command[3]);
+            } else {
+                if (command.length > 4) {
+                    setIndex(scriptExecutor, command[4]);
+                }
+            }
+        }
+
         Value v1 = scriptExecutor.getOrItselfValue(command[1]);
         Value v2 = scriptExecutor.getOrItselfValue(command[2]);
         if (v1.getClass() != v2.getClass()) {
@@ -50,10 +60,17 @@ public class If implements SpecialCommand {
             return true;
         }
         if (v1.asString().equals(v2.asString())) {
-            scriptExecutor.setIndex((int) asLong(command[3]));
+            setIndex(scriptExecutor, command[3]);
         } else if (command.length > 4) {
-            scriptExecutor.setIndex((int) asLong(command[4]));
+            setIndex(scriptExecutor, command[4]);
         }
         return true;
     }
+
+    private void setIndex(ScriptExecutor scriptExecutor, String name) {
+        int jp = scriptExecutor.jumpPoints.getOrDefault(name, -1);
+        if (jp != -1) {
+            scriptExecutor.setIndex(jp);
+        }
+    }
 }