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Diffstat (limited to 'src/Wetterhorn/Constraints.hs')
| -rw-r--r-- | src/Wetterhorn/Constraints.hs | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/Wetterhorn/Constraints.hs b/src/Wetterhorn/Constraints.hs new file mode 100644 index 0000000..cdc5afe --- /dev/null +++ b/src/Wetterhorn/Constraints.hs @@ -0,0 +1,12 @@ +-- | Contains useful constraints and constraint combinators. +module Wetterhorn.Constraints where + +-- | A null constraint. All types implement this. +class Unconstrained a + +instance Unconstrained a + +-- | Combines multiple constraints by 'And'ing them together. +class (c1 a, c2 a) => (&&&&) c1 c2 a + +instance (c1 a, c2 a) => (&&&&) c1 c2 a |