The way I learned it:

A tuple type is defined by the types inside it, so an (int,int) is not the same type as an (int, maybe(int)). With a one-tuple the type would just be (int) and that provides zero benefit.

Instead of trying to do `first (...my expression...)` to get the first element of the one tuple, it just becomes the value inside.

Sent from my iPhone

On Feb 24, 2016, at 7:02 PM, Imants Cekusins <imantc@gmail.com> wrote:

My guess is: tuple must contain 2+ elements.

Try to enter (1) in ghci. It is displayed as 1

Parentheses are only recognized as a tuple if there are elements separated by a comma. Otherwise an expression is assumed.

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