Checking core structure...
compile_project:10: no matches found: *.in
rm -f calc-core.jar `find . -name \*.class`
(cd src; javac -encoding UTF-8 `find . -name \*.java`)
./calc/Visitor.java:11: error: cannot find symbol
	public String visitFunction(Function c);
	                            ^
  symbol:   class Function
  location: interface Visitor
./calc/Visitor.java:12: error: cannot find symbol
	public String visitValue(Value c);
	                         ^
  symbol:   class Value
  location: interface Visitor
./calc/Evaluator.java:29: error: cannot find symbol
	public String visitFunction(Function c){}
	                            ^
  symbol:   class Function
  location: class Evaluator
./calc/Evaluator.java:31: error: cannot find symbol
	public String visitValue(Value c){}
	                         ^
  symbol:   class Value
  location: class Evaluator
./calc/Add.java:3: error: Add is not abstract and does not override abstract method getContent() in Content
public class Add extends BinaryFunction{
       ^
./calc/Sub.java:3: error: Sub is not abstract and does not override abstract method getContent() in Content
public class Sub extends BinaryFunction {
       ^
./calc/Mul.java:3: error: Mul is not abstract and does not override abstract method getContent() in Content
public class Mul extends BinaryFunction {
       ^
./calc/Div.java:3: error: Div is not abstract and does not override abstract method getContent() in Content
public class Div extends BinaryFunction {
       ^
./calc/Literal.java:3: error: Literal is not abstract and does not override abstract method getContent() in Content
 public class Literal implements Content {
        ^
./calc/Reference.java:3: error: Reference is not abstract and does not override abstract method getContent() in Content
 public class Reference implements Content {
        ^
./calc/Reference.java:22: error: incompatible types
	public int accept(Visitor v) { return v.visitReference(this); }
	                                                      ^
  required: int
  found:    String
./calc/Sheet.java:56: error: no suitable method found for put(int,Content)
	  _contents.put(content.getContent(), content);
	           ^
    method TreeMap.put(String,Content) is not applicable
      (actual argument int cannot be converted to String by method invocation conversion)
12 errors
make: *** [all] Error 1