Orchid XP v8 wrote:
>>> Haskell has automatic type inference, for example.
>>
>> Lots of languages have this a little. In C#
> 
> Just out of curiosity, just how new *is* C#?

Like 7 or 8 years. Newer versions are, of course, younger.

> ...there are statically-typed OO languages which aren't Java? [Or 
> Eiffel, which nobody ever uses.]

You're trolling here, right?

> All I know is that Eiffel makes it seem like this really exotic feature 
> that you "shouldn't need to use" under normal circumstances, and if you 
> find yourself using it, you've probably designed your program wrong.

I thnk you've misread that, since one of the primary purposes in the design 
of Eiffel was to provide a language where doing this tricky thing is right.

> Haskell, on the other hand, makes it trivial.

As long as you don't have inheritance, it *is* pretty trivial.

>> Integers are finite?
> They are if there fixed-precision. ;-)

Oh. I thought Haskell had bigints. Nevermind.

>> I've never seen it done that way. :-)
> Oh really? So how would you do it then?

Generally with the same class for nodes regardless of whether they're leaves 
or not.

> My point is that there are major classes of problems which *are* the 
> other way around, and for that ADTs win. 

Yep.

> For example, the parse tree of 
> an expression. You are almost never going to add new types of node to 
> that, but you *are* going to be adding new processing passes all the 
> time. 

I'd disagree with this, but OK. I get your point. I just think this specific 
example is probably wrong.

>> It also means you have to recompile everything whenever you change a 
>> type. Which kind of sucks when it takes several days to compile the 
>> system.
> 
> Are there systems in existence which actually take that long to compile?

Yep. Hell, it takes about 3 hours to compile the toolchain and 3 hours to 
compile Qt on my machine, and that's just C and C++ without anything 
sophisticated going on.

>> Huh? Javascript is about as OO as Smalltalk is. There's nothing in 
>> Javascript that is *not* an object.
> 
> 1. Smalltalk has classes. JavaScript does not.

Yes, it does.  Not in exactly the same way, mind. What do you think
    var d = new Date()
is doing there?

> 2. Smalltalk has encapsulation. JavaScript does not.

Yes, it does.  It's just harder and pointless.

>> Smalltalk doesn't have first-class functions. It has first class 
>> blocks, which are closures.
> 
> I won't pretend to comprehend what the difference is, but sure.

A function is a piece of code. A block is a reference to a piece of code 
that when evaluated returns a closure.  It's the same difference as between 
a class and an instance, or a lambda and a closure.

> Erm... no, not really.
> 
>   function foo(x) {...}
> 
>   var bar = foo;
> 
>   var x = bar(5);
> 
> No objects here, 

Bzzzt. You just don't know javascript very well. What object do you get when 
  foo or bar references "this"?

> Eiffel has... uh... "agents"? Which are basically GUI callback 
> functions, but we wouldn't want to have actual functions, would we?

I don't remember Eiffel well enough to remember that bit.

> Yeah. Databases have been transactional for decades, and many languages 
> can access a database. But STM is all internal to the program, and 
> implements multi-way blocking and conditional branching and all kinds of 
> craziness.

Right. And it has been implemented in database access code. Like, when you 
have "cloud" services. I think Google's cloud processing arguably uses STM. 
I'm pretty sure Erlang's Mnesia database works that way too.

> Heh. Better not tell that to Galois.com, Well-Typed.com, the authors of 
> the 1,000+ packages in the Hackage DB, or the likes of Facebook, AT&T, 
> Barclays Analytics or Linspire who all apparently use Haskell internally.

I think you missed "have to" there.

> Sure, Haskell is no Java, C# or PHP. But that's not to say that *nobody* 
> is using it...

I didn't say nobody is using it. I said you don't have to support it.

-- 
Darren New, San Diego CA, USA (PST)
   The question in today's corporate environment is not
   so much "what color is your parachute?" as it is
   "what color is your nose?"

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