Re: [Haskell-cafe] APIs

On Thu, 19 May 2005 ajb@spamcop.net wrote:

G'day all.

Quoting Jérémy Bobbio :

...

One of the best bad example is the use of boolean as arguments.

Oh, yes. That's a pet peeve of mine. About 99% of boolean arguments should be meaningful two-valued enumerated types. It's literally a one-liner to create such an enumerated type, so there's no excuse.

The documentation effect and type safety provided by two-valued enumerated types is indeed much greater. But one needs a conversion from Bool to the enumeration if one wants to pass the result of a logic operation to the function. What about records with named fields, especially if more options are needed? data CreateDirectoryOptions = Cons {createParents :: Bool} createDirectory (Cons {createParents = True}) "dir"