[Haskell-cafe] Re: [Haskell] Top Level <-

[Ganesh Sittampalam]

On Sun, 31 Aug 2008, Brandon S. Allbery KF8NH wrote:

> On 2008 Aug 31, at 10:20, Ganesh Sittampalam wrote:
>
>> I'm not sure of precisely what you mean here, but stdin, stdout and 
>> stderr are things provided by the OS to a process. That's what defines 
>> them as having process scope, not something the Haskell language or RTS 
>> does.
>
> But their representations in Haskell must have the same scope and are 
> therefore de facto global variables.

Yep, but this is not Haskell providing a way to make global variables, it 
is just providing an interface to ones that already exist. The point is 
that the RTS can't provide (process-scope) global variables of its own 
invention, because it can't guarantee to be running at the top-level of a 
process, which it needs to be in order to control their construction.

Cheers,

Ganesh