Safe Haskell | Safe |
---|---|

Language | Haskell2010 |

# Documentation

Given a constructor `K`

for a type `T`

which implements `Data`

,
and a value `a`

of type `T`

, 'is K a' evaluates `a`

to WHNF, and
returns True if `K`

is the head constructor of the result.

$(is 'K) ≡ is K

not . is K ≡ isNot K