The function name.
The function parameters and return type.
The definition of the function.
Whether the function was registered.
dstring func = "(Number)(Number)"d; dstring def = "x1"d; dstring name = "f"d; assert(registerFunction(name, func, def)); assert(!registerFunction(name, func, def)); //No registering an already-existing function.
Registers a valid function that doesn't already exist.