Passing around a list of differently typed functions

[Evan Davis via Digitalmars-d-learn]

As the subject says, I would like to pass around an array of 
functions. The trick is, that the functions have different type 
signatures. Is there a way to put the two functions

int foo(int a, int b);
bool bar(bool a, bool b);

into one array, that I can pass around and cast as necessary?

Thanks, Evan