Added function call and function definition

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

@@ -0,0 +1,22 @@
+package de.hsrm.compiler.Klang.nodes;
+
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class FunctionDefinition extends Node {
+
+  public String name;
+  public String[] parameters;
+  public Block block;
+
+  public FunctionDefinition(String name, String[] parameters, Block block) {
+    this.name = name;
+    this.parameters = parameters;
+    this.block = block;
+  }
+
+
+  @Override
+  public <R> R welcome(Visitor<R> v) {
+    return v.visit(this);
+  }
+}

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

@@ -0,0 +1,20 @@
+package de.hsrm.compiler.Klang.nodes;
+
+import de.hsrm.compiler.Klang.nodes.expressions.Expression;
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class Program extends Node {
+  
+  public FunctionDefinition[] funcs;
+  public Expression expression;
+
+  public Program(FunctionDefinition[] funcs, Expression expression) {
+    this.funcs = funcs;
+    this.expression = expression;
+  }
+
+  @Override
+  public <R> R welcome(Visitor<R> v) {
+    return v.visit(this);
+  }
+}

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

@@ -0,0 +1,19 @@
+package de.hsrm.compiler.Klang.nodes.expressions;
+
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class FunctionCall extends Expression {
+
+  public String name;
+  public Expression[] arguments;
+
+  public FunctionCall(String name, Expression[] arguments) {
+    this.name = name;
+    this.arguments = arguments;
+  }
+
+  @Override
+  public <R> R welcome(Visitor<R> v) {
+    return v.visit(this);
+  }
+}