partial

A nullary type class for partial functions

Introduction

Use the Partial type class to track your partial functions. For example:

{-# LANGUAGE NullaryTypeClasses #-}

import Data.List.Partial

cadr :: (Partial) => [a] -> a
cadr = head . head

As an application developer, either opt into partial functions globally by declaring an instance of the Partial type class:

instance Partial

or run partial functions selectively using the partial function:

ghci> partial $ cadr [1, 2, 3]
2