Just package:express

The Just constructor lifted over the Expr type. This works for the Bool, Int, Char argument types and their lists.

> just zero
Just 0 :: Maybe Int
> just false
Just False :: Maybe Bool

The Just constructor of the Bool element type encoded as an Expr.

The Just constructor of the Int element type encoded as an Expr.

Encodes a Name as a String. This is useful when generating error messages.

> showJustName ''Int
"Int"

> showJustName ''String
"String"

> showJustName ''Maybe
"Maybe"