Re: function object design problem
mati wrote:
Suppose there is some complex functor, and we are using some helper
functions inside:
are you gonna make it templated?
or you just forgot to type it?
class Func {
private:
inline void helper(...) {...}
public:
RetType operator()(const &data, Type1 param1, Type2 param2, ...)
{
const Type1 precomputed_param1 = some_heavy_math(param1, ...);
...
... //with excessive use of helper functions
}
};
However, this helper function needs a lots of parameters, some
precomputed in operator(), some given to it (ex. param1,param2).
Question is - how to pass data references/pointers and parameters to the\
pointer is not an issue.
on reference, you can use
template <class T>
class RefHolder
{
T& ref_;
public:
RefHolder(T& ref) : ref_(ref) {}
operator T& () const
{
return ref_;
}
};
template <class T>
inline RefHolder<T> ByRef(T& t)
{
return RefHolder<T>(t);
}
as wrapper
helper functions? With a remark, that helpers needs to be fast (inline
is a must).
Two ideas are:
1. Pass to function by reference/value.
2. Use private Func data members.
However, 1. yelds large argument list, and 2. can't deal with parameters
passed to operator() as references, also parameters can't be const
using RefHolder, the constness will be traited out.
(which is a good thing).
I haven't come up with anything 100% nice and fast, so I'm asking here,
maybe there is a way.
--
Thanks
Barry