Re: [Boost-users] [iterator] Writable transform_iterator: how to?

From: Nicola (nvitacolonna_at_[hidden])
Date: 2008-04-11 06:09:50

In article 
<A194A82A1A084C4C8A29AD16E363B5F8FCDE36_at_WIN2003s325.its.local>,
 "Patrick Loney" <Patrick.Loney_at_[hidden]> wrote:

> struct f : public std::unary_function<int, int&> {
>    int operator()(int& x) { return x; } };

No, nor does

struct f : public std::unary_function<int, int> {
   int operator()(int x) { return x; } };

or

struct f {
   typedef int& result_type;
   result_type operator()(int& x) { return x; }
};

The compiler complains upon dereferencing. But my goal is to be able to 
modify the iterator's value (i.e., to write *it = value), so the return 
type of the function object must be a reference. Maybe, I can use 
iterator_adaptor instead of transform_iterator?

I have forgotten to mention that I am using Boost 1.34.1.

Nicola