Nitpicks

This page is for people to record nitpicks about the Haskell language.

A "nitpick", in this case, is something that is annoying or could be improved, but is probably not important enough to justify the added complexity of tacking it on as an extension or breaking existing code.

In other words, if we could go back in time and fix it before it happened, we probably would, but now it would probably be too onerous.

Ideally, these nitpicks could help to inform future proposals or compatibility-breaking changes to the language. Even if they may be too onerous to change right now, it's possible that it would make sense to address them at some other time.

If the nitpick has been discussed at length, please post a link to the discussion.

Syntax-related nitpicks

• Re-naming data, newtype, and type to type, newtype, and alias, respectively. See https://mail.haskell.org/pipermail/haskell-cafe/2015-August/120724.html .
• Replace the special if-then-else syntax with a standard prelude function. See https://wiki.haskell.org/If-then-else .
• Introduce a newtype/data with the symbol ::= instead of =, as this is confusing with the equal sign. See https://mail.haskell.org/pipermail/haskell-cafe/2015-August/120724.html
• A type should be introduced with the symbol : instead of :: as in many other languages and mathematical papers. Conversely :: should be used as the cons operator.
• The kind for inhabited types * is not an operator. See https://ghc.haskell.org/trac/ghc/wiki/DependentHaskell/Phase1#ishardtoparse
• default is a useful name for a variable, but it's taken up as a keyword for the rarely used defaulting declaration. DefaultSignatures adds a more useful use though.
• Allow hyphenated (à la scheme) identifiers like example-identifier, which some of us prefer to uglyCamelCase.

Base-related nitpicks

• Re-naming fmap to map. This has been discussed at length; see http://stackoverflow.com/questions/6824255/whats-the-point-of-map-in-haskell-when-there-is-fmap/6824333 and https://mail.haskell.org/pipermail/haskell-prime/2006-August/thread.html
• Cutting up Num, which is a mess of various operations one may not want to all define on some type; for example (+) makes sense for vectors in ℝ³ but (*) doesn't. Also, fromIntegral is useful for some types where the full complement of numeric operators aren't.
• Data.List.nub and other "Set" operations should be restricted to Ord not Eq in order to reduce their complexity. It is very unlikely for anyone to create a datatype that can support Eq but not Ord. Data.Set in the "container" package assumes Ord as well.