[Haskell-beginners] Type constructors sharing a common field

Benjamin Edwards edwards.benj at gmail.com
Tue Apr 29 10:45:00 UTC 2014

In addition to the comments made by Daniel, as a general rule, you don’t
want a sum type with selectors functions as your example stands, because
you can end up with compiling programs like this:

module Main where
main :: IO ()main =
    let p = Child 10
        age = adultAge p
     in print age

this craps out with an error at runtime.
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