Re: [boost] [contract] Contract Programming Library

Subject: Re: [boost] [contract] Contract Programming Library
From: Lorenzo Caminiti (lorcaminiti_at_[hidden])
Date: 2010-02-18 23:45:12

Hello Andrzej,

Sorry, I realize I did not complete the loop example:

void f(std::vector v, const size_t& n) {
   size_t i = 0;
   CONTRACT_ASSERT_BLOCK_INVARIANT( i == 0 ); // Block inv.
   for (CONTRACT_INIT_LOOP_VARIANT; i < v.size(); ++i) {
       CONTRACT_ASSERT_BLOCK_INVARIANT( i < v.size() ); // Block inv
as loop inv.
       CONTRACT_ASSERT_LOOP_VARIANT( v.size() - i ); // Loop variant.
       ...
   }
}

On Tue, Feb 16, 2010 at 3:01 PM, Andrzej Krzemienski <akrzemi1_at_[hidden]> wrote:
> use a medium size range, the performance can kill me. I would like to
> disable checking of this assertion, but at the same time there is no
> reason to disable others. Would you consider providing a way to
> selectively disable asserts? some assertion level?

Yes, I will consider this in the future. Also, I might want to check
inv/pre/post for most of the classes I compile but not for a few
templates part of a library that I trust (e.g., Boost). So it would be
nice to select different contract checking levels (at least at
run-time) based on class name or similar.

> (2).
> Usually public member functions would be used to express DbC
> assertions. Do you disable assertions in public functions that are
> called only to evaluate other assertions in order to avoid recursive
> calls?

Yes, the library policy is to disable assertion checking within
assertions and to disable class invariants checking for nested
function calls (public or not) (requirements from [Meyer1997],
[Ottosen2004], and [Crowl2006]). Different policies could be
implemented but this one avoids infinite recursion well in my
experience.

Regards,
Lorenzo