On Mon, 1 Sep 2008, John Meacham wrote:
On Mon, Sep 01, 2008 at 10:45:05PM +0100, Ganesh Sittampalam wrote:
Actually all this use of the tainted and derogatory term "global
variable" is causing me to be imprecise. All MVars/IORefs have "global"
main/process scope whether or not they're bound to something at the
top level.
"Global variable" is exactly the right term to use, if we are following
the terminology of other languages. We don't call the result of
malloc/new etc a "global variable", unless it is assigned to something
with top-level scope.
global variable is not a very precise term in other languages for
various platforms too a lot of times. for instance, windows dll's have
the ability to share individual variables across all loadings of said
dll. (for better or worse.)
Interesting, is this just within a single process?
Haskell certainly has more advanced scoping capabilities than other
languages so we need a more refined terminology. I think 'IO scope' is
the more precise term, as it implys the scope is that of the IO monad
state. which may or may not correspond to some external 'process scope'.
Hmm, to me that implies that if the IO monad stops and restarts, e.g. when
a Haskell library is being called from an external library, then the scope
stops and starts again (which I presume is not the intention of <- ?)
But I don't really care that much about the name, if there is consensus on
what to call it that doesn't cause ambiguities with OS processes etc.
Cheers,
Ganesh
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