Re: [Boost-users] [Lambda] nitty gritty detail...?

Subject: Re: [Boost-users] [Lambda] nitty gritty detail...?
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2011-03-31 14:38:33

AMDG

On 03/31/2011 11:27 AM, Robert Jones wrote:
> On Thu, Mar 31, 2011 at 4:47 PM, Steven Watanabe<watanabesj_at_[hidden]>wrote:
>>
>> On 03/31/2011 08:29 AM, Robert Jones wrote:
>>
>>>  From Bjorn Karlsson's book, P297...
>>>>
>>>
>>> int i;
>>> int value = 12;
>>> var(i) = ( if_then_else_return( _1>=10, constant(10),_1) )(value);
>>>
>>> Why does the assignment LHS need to be wrapped in var()?
>>>
>>>
>> Because operator= must be a member function.
>>
>>
> Nope, still not getting it! Stop me when I err...
>
> if_then_else_return(...) defines a unary functor
> it_then_else_return(...)( value) evaluates that functor, and returns what?
>
> Some type of integer I think?

Yes.

> So doesn't the assignment simply perform
> assignment of an integer, by copy? And that doesn't need operator= to
> a member of anything?
>

Oh, I see.  As written, the code doesn't make much
sense, so my mind automatically translated it into

(var(i) = if_then_else_return( _1>=10, constant(10),_1) )(value);

In Christ,
Steven Watanabe