Added if statement

src/main/java/de/hsrm/compiler/Klang/Klang.java

@@ -19,9 +19,9 @@ public class Klang {
     KlangParser parser = new KlangParser(tokens);
 
     ParseTree tree = parser.parse(); // begin parsing at init rule
-    StringBuilder sb = new StringBuilder();
-    JSVisitor visitor = new JSVisitor(sb);
+    // StringBuilder sb = new StringBuilder();
+    Visitor visitor = new Visitor();
     visitor.visit(tree);
-    System.out.println(sb.toString());
+    // System.out.println(sb.toString());
   }
 }

src/main/java/de/hsrm/compiler/Klang/Visitor.java

@@ -9,6 +9,17 @@ public class Visitor extends KlangBaseVisitor<Value> {
     return value;
   }
 
+  @Override
+  public Value visitIf_statement(KlangParser.If_statementContext ctx) {
+    Value cond = this.visit(ctx.expression());
+    if (cond.asInteger() != 0) {
+      this.visit(ctx.braced_block(0));
+    } else if (ctx.braced_block().size() > 1) {
+      this.visit(ctx.braced_block(1));
+    }
+    return null;
+  }
+
   @Override
   public Value visitMultiplicationExpression(KlangParser.MultiplicationExpressionContext ctx) {
     Value left = this.visit(ctx.atom(0));
@@ -27,7 +38,8 @@ public class Visitor extends KlangBaseVisitor<Value> {
     case KlangParser.SUB:
       return new Value(left.asInteger() - right.asInteger());
     default:
-      throw new RuntimeException("Unknown operator for additive expression: "+ KlangParser.VOCABULARY.getDisplayName(ctx.op.getType()));
+      throw new RuntimeException(
+          "Unknown operator for additive expression: " + KlangParser.VOCABULARY.getDisplayName(ctx.op.getType()));
     }
   }
 
@@ -44,6 +56,11 @@ public class Visitor extends KlangBaseVisitor<Value> {
     return new Value(-value.asInteger());
   }
 
+  @Override
+  public Value visitAtomExpression(KlangParser.AtomExpressionContext ctx) {
+    return this.visit(ctx.atom());
+  }
+
   @Override
   public Value visitIntAtom(KlangParser.IntAtomContext ctx) {
     return new Value(Integer.parseInt(ctx.getText()));