[Haskell-cafe] Re: Top Level <-

[Ganesh Sittampalam]

On Sun, 7 Sep 2008, Brandon S. Allbery KF8NH wrote:

>> plug-in that is reloaded in different forms again and again. And I see 
>> module K which does something I want, so I use it. It so happens that K 
>> uses M, which has a <-. If I knew that using K in my plug-in would cause a 
>> memory leak, I would avoid doing so; but since the whole point of <- is to 
>> avoid making the need for some state visible in the API.
>
> False, as it's in ACIO and therefore advertises that it will "leak 
> memory" in the name of correct behavior.

I thought ACIO was a restriction on the thing on the right hand side of 
the <-? How does the module itself advertise its use of this 
(transitively) to users?

> Since you consider memory leaks to be worse than correct behavior,

Not leaking memory is *part* of correct behaviour. If <- is to be created 
at all, it should be created with restrictions that make it capable of 
guaranteeing correct behaviour.

> (But you might want to go look at that list of modules which do global 
> variable initialization and therefore aren't entirely trustworthy unless 
> something like ACIO exists.)

We should fix them (and their interface) so this doesn't happen, rather 
than standardising something broken.

Ganesh