[erlang-questions] erlang sucks

Ulf Wiger (TN/EAB) ulf.wiger@REDACTED
Fri Mar 14 13:10:54 CET 2008


Thomas Lindgren skrev:
> --- "Ulf Wiger (TN/EAB)" <ulf.wiger@REDACTED>
> wrote:
> 
>> Raoul Duke skrev:
>>
>>> this has nothing to do with the reality of Erlang
>> :-) but presumably
>>> in a sufficiently powerful type system you could
>> constrain the guards
>>> to be safe?
>> Given the state of type checking in Erlang nowadays,
>> this might indeed
>> be ripe for some research and prototyping.
> 
> Marking functions as safe/pure is straightforward when
> you have the whole program -- just mark the uncertain
> cases as impure -- so you could easily verify that a
> certain software release only uses safe guards.
> 
> As far as I can see, the main problem would be
> piecemeal use of code, such as in ad hoc hot code
> loading. But even here, it seems you could reject the
> module at load time by (a) enclosing suitable
> annotations with the beam file and (b) a quick bit of
> load-time analysis.

...or mark calls to external functions as impure/unsafe.

I think this is a reasonable restriction.

BR,
Ulf W



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