any news on const/invariant?

[James Dennett]

Bruce Adams wrote:

[snip]

> I personally agree that const on value types in C++ is a stupid idea.
> Meyers recommends it (effective C++) for the following case however:
> 
> T operator*(T,T)
> 
> if ((a*b)=c)) { //oops!
> 
> instead of:
> 
> if ((a*b)==c) {
> 
> Personally I prefer to use lint to disallow assignment in boolean
> expressions.

A good compiler can do that for you too (though using lint
is a fine idea to supplement even a good compiler).

(Scott's advice here doesn't suit me; "do as the ints do" is

> There is a school that uses const value types even for builtins like int.
> I am currently trying to convince people at work that it is pointless
> and neither
> being const correct not just a style thing.

It's not pointless, and it's not just a style thing.  It avoids
defects, and it makes code clearer for those who are used to
both styles.  Maybe instead of setting out to convince people of
something, you could set out to discover which solution really
works better in practice.  Using const has known advantages in
expressiveness and defect elimination; apart from saving
typing, what's the benefit of *not* recording the design
decision that some value will not change during execution?
It's a very lightweight, compile-time enforced invariant check.

-- James