RE: RE: [boost] Optimization of MPL expression?

From: Brock Peabody (brock.peabody_at_[hidden])
Date: 2003-09-11 18:46:26

> -----Original Message-----
> From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]]
> On Behalf Of JOAQUIN LOPEZ MU?Z
> Sent: Thursday, September 11, 2003 2:52 PM
> To: boost_at_[hidden]
> Cc: joaquin_at_[hidden]
> Subject: Re: RE: [boost] Optimization of MPL expression?

[...]

> Btw indexed_set has had a cold response --kinda frustrating :)
> Now that you have downloaded it, have you had the chance to
> take a look at it? Comments, suggestions? Thx in advance.

OK, first I'd like to say that I think this is a great idea and your
implementation looks very good.  A few questions/suggestions I thought of:

1) Why use index_list instead of letting the user choose one of the mpl
containers?

2) I can't think of any way to do it, but it would be nice to be able to
say:

   member<&employee::name>

instead of:

   member<employee,int,&employee::name>

maybe this isn't possible.

3) What do you think of the possibility of automatically deducing (unique)
indexes from key type?  For instance:

   indexed_set<
      employee,
      unique<member<employee,std::string,&employee::name> >,
      unique<member<employee,double,&employee::height> >,
      unique<member<employee,double,&employee::weight> >
   > employees;

   cout << "Bob's age: " << employees.at("bob").age << endl;

This is legal because there is only one unique key type that char* is
convertible to.

   cout << "Employee that weighs 150.3: " << employees.at(150.3) << endl;

This is invalid because 150.3 could refer to height or weight.

---
Anyway, I know I have needed this type of library many times in the past and
I think your implementation of it is excellent.  Have you submitted it for
review?
Brock Peabody