>>   integer * string
>> which seems a rather perverse choice. 
> 
> Cartesian product of integers and strings.  I'm not sure what a "sum 
> type" would be.

Either Int String

is a sum type. The set of possible values is the *sum of* the set of 
possible Int values and the set of possible String values.

Whereas... well, you understand what a Cartesian product is already, right?

Haskell's "algebraic data types" are sum types of product types. (The 
sum may contain only one summand, but a sum none the less. Actually, if 
you enable the EmptyDataDecls extension, zero summands are permissible...)

>> instead of "(True, 5)"? It would be clearer...)
> 
> Wait till you get to python, where the tuple constructor is actually the 
> comma, the parens are optional, and you try to figure out how to write a 
> one-element tuple literal, or the empty tuple.

Oh, the *type constructor* for a 2-tuple is "(,)", and for a 3-tuple 
it's "(,,)".

So if you want to be 73% anal, you can write "(,) String Integer" 
instead of "(String,Integer)". :-}

Off the top of my head, I don't *believe* this works with value 
constructors... No, wait. I'm wrong; it does work.

   (,,) :: a -> b -> c -> (a,b,c)

This means we can write

   zip = zipWith (,)

Eat THAT and smoke it! o_O

(Similarly, "[Char]" can also be written "[] Char".)

>> Haskell makes the rather illogical choice of using "--" as the start 
>> marker for a comment. 
> 
> Common in a lot of other languages like SQL and Ada. FWIW.

I know Eiffel uses it. But then, Eiffel is weird.

>> Ocaml uses the even stranger choice of "(* ... *)". 
> 
> Which is Pascal for comments, if your keyboard (punched cards) don't 
> have curly braces. FWIW.

...more useless information to add to my collection! o_O

Then again, in Pascal "(*)" is not a meaningful thing to write in the 
first place. ;-)

PS. I'm loving the way Haskell uses curly brackets for explicit 
grouping, AND ALSO for named-field syntax. Way to use the exact same 
symbol for two unrelated things that you might want to do AT THE SAME TIME!

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message