Re: [Boost-users] [Boost.Assign] list_of::range without an initial (single) element?

Subject: Re: [Boost-users] [Boost.Assign] list_of::range without an initial (single) element?
From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2010-06-17 07:46:23

Nat Goodspeed skrev:
> Thorsten Ottosen wrote:
> 
>> Nat Goodspeed skrev:
>>> Thorsten Ottosen wrote:
>>>
>>>>>> However, list_of<int>() inserts a default value (so that
>>>>>> list_of<int>().range(a).range(b) == {0,1,2,3,4}).  
>>>>
>>>> Maybe we should add
>>>>
>>>>    empty_list_of<int>()
>>>>
>>>> ? It's quite trivial to add.
>>>
>>> Does list_of<T>() have a default value for its T parameter?
>>
>> No, how could it?

... as it cannot assume what T will be.

> In that case, I'm confused about why list_of<int>() inserts a default 
> value.

It was a consistency issue. Consider

   list_of<int>()(42); // 0, 42
   list_of<int>(42)(); // 42, 0
   list_of(42)();      // 42, 0

would you expect that to be any different?

-Thorsten