id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
4969	transform_iterator won't work with non-const operator() call for function object	zhuo.qiang@…	jeffrey.hellrung	"transform_iterator declare it's copied function object as:
{{{#!c++
    UnaryFunc m_f;
}}}

And it's dereference function as:
{{{#!c++
    typename super_t::reference dereference() const
    { return m_f(*this->base()); }
}}}
which makes it impossible to cooperate with function object with non-const operator() overloading, and and it will also make transformed adaptor in boost::range not work:
{{{#!c++
struct Fun
{
    typedef bool result_type;
    
    bool operator()(int a)
    {
        return a != 1;
    }
};
    Fun f;
    boost::find(all|boost::adaptors::transformed(f), true);
}}}

A boost::ref won't work here since the result has no result_type defined

And the only solution would be using a boost::function to hold the original function object, however, doing so will give unnecessary run time cost.

I suggest change the UnaryFunc m_f; definition to mutable, so that it will work with non-const functor.
{{{#!c++
    UnaryFunc mutable m_f;
}}}
"	Bugs	new	To Be Determined	iterator	Boost 1.45.0	Regression