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

Adrian Hey ahey at iee.org
Thu Aug 28 12:26:27 EDT 2008

Jonathan Cast wrote:
> On Thu, 2008-08-28 at 10:00 +0100, Adrian Hey wrote:
>> Lennart Augustsson wrote:
>>  > I don't don't think global variables should be banned, I just think
>>  > they should be severly discouraged.
>> If you're saying a language should not provide a sound way to do
>> this (as I believe you are), then AFAICT for all practical purposes
>> you *are* saying you think global variables should be banned.
>> Where are we going to be if the unsafePerformIO hack ever becomes
>> *really* unsafe?
>> and..
>>> I'm certain you can write a kernel in Haskell where the only use of
>>> global variables is those that hardware interfacing forces you to use.
>> But what you haven't explained is why this is even desirable? I don't
>> doubt it's true in an academic sense if you don't mind sacrificing
>> safety 
> What `safety' is being sacrificed?
>> and modularity.
> What modularity?

As I've pointed out several times already you can find simple examples
in the standard haskell libs. So far nobody has accepted my challenge to
re-implement any of these "competantly" (I.E. avoiding the use of global

Why don't you try it with Data.Unique and find out :-)

Adrian Hey

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