implement node for struct field access expression

src/main/java/de/hsrm/compiler/Klang/nodes/expressions/StructFieldAccessExpression.java

@@ -0,0 +1,18 @@
+package de.hsrm.compiler.Klang.nodes.expressions;
+
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class StructFieldAccessExpression extends Expression {
+  public String varName;
+  public String[] path;
+
+  public StructFieldAccessExpression(String varName, String[] path) {
+    this.varName = varName;
+    this.path = path;
+  }
+
+  @Override
+  public <R> R welcome(Visitor<R> v) {
+    return v.visit(this);
+  }
+}