[Haskell-cafe] Data & newtype differences. Today: strictness

Yitzchak Gale gale at sefer.org
Sun Jan 22 15:17:55 CET 2012

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

"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)..."


[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

More information about the Haskell-Cafe mailing list