[erlang-questions] Extensions to comprehensions eeps

Anthony Shipman <>
Thu Jul 31 11:47:01 CEST 2008


On Thu, 31 Jul 2008 11:48:07 am Richard A. O'Keefe wrote:
> > The funny symbols are a kind of type annotation by stealth that is  
> > quite
> > irregular in the language.
>
> When it is right out there in the open, how is it "stealth"?
>
> Please clarify how <- vs <= (in the existing language)
> is "type annotation by stealth" and 'and' vs 'band' is not.

People claim that an advantage of dynamic languages is that you don't have to 
put type annotations on variables.  The language operations are, as far as 
possible, polymorphic at run time. So you can change the type of a variable 
and not have to go through the source updating type declarations etc. This is 
supposed to make for more rapid prototyping.

But then you get into the details of Erlang and find that there are 
effectively type annotations all over the place  to help the compiler. They 
don't appear as explicit type annotations, they sneak in in the punctuation.

The existing <- vs <= is just as much an error. I would like further 
development in Erlang to fix these errors rather than add many more funny 
symbols. Otherwise the language would end up looking like haskell.

-- 
Anthony Shipman                    Mamas don't let your babies 
                   grow up to be outsourced.



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