2012/1/22 Yitzchak Gale <gale@sefer.org>

Yves Parès wrote:
>> Is there some litterature expliciting in a less empiric way than I did the
>> differences like this between data and newtype? I've never come against
>> such documentation through all my learning of Haskell, yet I think it's an
>> important point.

Roman Cheplyaka wrote:
> See the Haskell report, section 3.17.2 "Informal Semantics of Pattern
> Matching" [1].

And section 4.2.3 of the report [2] addresses exactly your points very
explicitly:

"A type created by newtype differs from an algebraic datatype in that...
The following examples clarify the differences between data
(algebraic datatypes), type (type synonyms), and newtype
(renaming types)..."

Regards,
Yitz

[1] http://www.haskell.org/onlinereport/haskell2010/haskellch3.html#x8-600003.17.2
[2] http://www.haskell.org/onlinereport/haskell2010/haskellch4.html#x10-740004.2.3