Why is such a definition of a null function in Haskell Prelude so strange?

Question

The function definition nullin Prelude is as follows:

null             :: [a] -> Bool
null []          =  True
null (_:_)       =  False

What confused me is the third line of the definition, why she writes:

null(_:_)        = False

Instead:

null any = False

Does it have anything to do with compiler optimization?

Answer 1

Does it have anything to do with compiler optimization?

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