Haskell Language Common GHC Language Extensions TupleSections
Example
A syntactic extension that allows applying the tuple constructor (which is an operator) in a section way:
(a,b) == (,) a b
-- With TupleSections
(a,b) == (,) a b == (a,) b == (,b) a
N-tuples
It also works for tuples with arity greater than two
(,2,) 1 3 == (1,2,3)
Mapping
This can be useful in other places where sections are used:
map (,"tag") [1,2,3] == [(1,"tag"), (2, "tag"), (3, "tag")]
The above example without this extension would look like this:
map (\a -> (a, "tag")) [1,2,3]
