Added functionality to analyze AST for all defined functions

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

@@ -0,0 +1,51 @@
+package de.hsrm.compiler.Klang;
+
+import java.util.Map;
+import java.util.TreeMap;
+
+import de.hsrm.compiler.Klang.types.*;
+import de.hsrm.compiler.Klang.helper.*;
+
+public class GetFunctions extends KlangBaseVisitor<Void> {
+
+  private Map<String, FunctionInformation> funcs;
+
+  public GetFunctions(Map<String, FunctionInformation> funcs) {
+    this.funcs = funcs;
+  }
+
+  @Override
+  public Void visitProgram(KlangParser.ProgramContext ctx) {
+    for (int i = 0; i < ctx.functionDef().size(); i++) {
+      this.visit(ctx.functionDef(i));
+    }
+    return null;
+  }
+
+  @Override
+  public Void visitFunctionDef(KlangParser.FunctionDefContext ctx) {
+    String name = ctx.funcName.getText();
+
+    if (this.funcs.containsKey(name)) {
+      throw new Error("Function " + name + " defined multiple times");
+    }
+    
+    Type returnType = Type.getByName(ctx.returnType.type().getText());
+
+    TreeMap<String, Type> parameters = new TreeMap<String, Type>();
+
+    // Process the paremter list by visiting every paremter in it
+    int paramCount = ctx.params.parameter().size();
+    Type[] signature = new Type[paramCount];
+    for (int i = 0; i < paramCount; i++) {
+      Type paramType = Type.getByName(ctx.params.parameter(i).type_annotation().getText());
+      String paramName = ctx.params.parameter(i).IDENT().getText();
+      parameters.put(paramName, paramType);
+      signature[i] = paramType;
+    }
+
+    FunctionInformation information = new FunctionInformation(name, returnType, parameters, signature);
+    this.funcs.put(name, information);
+    return null;
+  }
+}