[Haskell-cafe] type metaphysics

Ketil Malde ketil at malde.org
Mon Feb 2 15:25:11 EST 2009

Gregg Reynolds <dev at mobileink.com> writes:

> Just shorthand for something like "data Tcon a = Dcon a", applied to Int.
> Any data constructor expression using an Int will yield a value of type Tcon
> Int.

Right.  But then the set of values is isomorphic to the set of Ints,

>> I don't follow this argument.  Are you saying you can remove a
>> data constructor from a type, and still have the same type?  And
>> because of this, the values of the type do not constitute a set?

> Yep.  

I don't see why you would consider it the same type.  Since, given any
two data types, I could remove all the data constructors, this would
make them, and by extension, all types the same, wouldn't it?

If I haven't seen further, it is by standing in the footprints of giants

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