Why the world needs Haskell
I don't have much experience with haskell beyond Learn You A Haskell (a book), but I wonder how beneficial the no null pointer errors are in practice.<p>The way haskell handles this reminds me of checked exceptions in Java.  In java if you read from a file, your code won't compile unless you have a catch block that handles the possibility of an IO exception.  This is called a checked exception because you have to check for the possibility or else your code won't compile.<p>I know many Java programmers handle checked exceptions by wrapping the checked exception in a unchecked exception so they don't have to deal with it.  Don't Haskell developers end up doing the same thing with their Maybe concept?<p>Haskell avoids null by using a Maybe type/class (I always forget the terminology).  A Maybe can evaluate to either a value or a type that represents the absence of a value.  (This is an oversimplification for the consideration of people who know nothing about Haskell)<p>For example, you've got an associative map data type and you find an element in there.  At the time of writing the code you "knew" that the element "has to be there".  Haskell makes you deal with the possibility that it's not.  Won't most developers just end up throwing an exception in that case so they don't have to deal with the impossible possibility?  Then, x months from now when the code gets changed so that the map won't have the element there, all the sudden your code gets an error.  How is this different from a null pointer exception in any other language?<p>(Part of me is ignorant and part of me is playing the devil's advocate.)