RE: [boost] Interval Library and comparison operators

From: David Bergman (davidb_at_[hidden])
Date: 2002-09-06 10:14:09

Peter,

The first argument, of being "STL-compatible" is reasonable, the second
is not. I argue that the user should be aware that he is dealing with a
partial order (if the order is such, such as '<' being subset) when
coding, so, yes, he might be forced to change the logic (in this case
control flow) when going from a total to a partial order...

/David

-----Original Message-----
From: boost-bounces_at_[hidden]
[mailto:boost-bounces_at_[hidden]] On Behalf Of Peter Dimov
Sent: Friday, September 06, 2002 8:34 AM
To: boost_at_[hidden]
Subject: Re: [boost] Interval Library and comparison operators

From: "David Bergman" <davidb_at_[hidden]>
>
> BUT, the prime reason for keeping the STL convenience implementation 
> of '<=' being '!>' was in order to be "compatible" with STL, according

> to Herve and Guillaume, in spite of the induced "equivalence" not 
> being an equivalence at all. Thus, I somehow got the idea that it was 
> important.

Having an "STL-compatible" operator< is important if you want to use STL
algorithms or associative containers with intervals without an explicit
comparator.

Having operator<= that is !> is important if you want to prevent user
mistakes, such as replacing

if(!(x < y))

with

if(y >= x)

There is always the option of not defining <= at all.

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