[Haskell-cafe] Execution Contexts

[Jules Bean]

On 27 Nov 2004, at 00:59, Benjamin Franksen wrote:

> I finally understood that George Russell's Library is not really about 
> global
> variables. Rather it is about what I want to call 'execution 
> contexts', which
> are -- as Marcin Kowalczyk observed -- a restricted form of dynamically
> scoped variables.

yes.

[snip]

> type XIO a = StateT Context IO a
>

...which, amusingly, brings us almost full circle to the message which 
sparked off this particular iteration of the Great Global Variables 
Debate:

http://groups.google.com/groups?selm=fa.hvrd8p7.nmg2r7%40ifi.uio.no

..which uses StateT Env IO

Although your work is rather more complete than what I sketch in that 
message.

A problem is the ability to pass callbacks to external libraries...

Jules