beh.idr

module Main

Semigroup b => Semigroup (a -> b) where
  f <+> g = \x => f x <+> g x

Monoid b => Monoid (a -> b) where
  neutral = const neutral

[all] Semigroup Bool where
  x <+> y  = x && y

via : Semigroup b -> Semigroup (a -> b)
via r = let _ = r in %search

alphaNum : Char -> Bool
-- alphaNum = (isDigit <+> isAlpha) @{let _ = all in %search}
alphaNum = (isDigit <+> isAlpha) @{via all}