Another feature which would be cool for an IDE is: "implement instance". So you automatically get to see all the functions of a type class you need to implement. Using C#/Java, this is used all over the place.
sounds potentially useful, but perhaps not quite as useful as one might expect: if you only want to see all the class methods, hugs/ghci provide the ':info' command (and haskell modes tend to provide access to that). $ ghc -e ':i Monad' class Monad m where (>>=) :: m a -> (a -> m b) -> m b (>>) :: m a -> m b -> m b return :: a -> m a fail :: String -> m a -- Defined in GHC.Base instance Monad Maybe -- Defined in Data.Maybe instance Monad IO -- Defined in GHC.IOBase instance Monad [] -- Defined in GHC.Base with a little bit of filtering and replacing, we get $ ghc -e ':i Monad' | sed -n '/^class/,/-- Defined in/{s/class/instance/;p}' instance Monad m where (>>=) :: m a -> (a -> m b) -> m b (>>) :: m a -> m b -> m b return :: a -> m a fail :: String -> m a -- Defined in GHC.Base i've used sed here, to keep it editor-independent, one can do the equivalent within emacs/vim, without sed. now, if one wanted to save typing, one might want to translate the type declarations into definition templates, but the type has more information than such template, and there are many forms of definition that fit a type, so having to replace the type declarations with definitions is perhaps as good as it gets? a similarly useful code template generation transformation would be to introduce complete case distinctions over sum types, so that f x = undefined would, if we knew (x::Maybe a), become f (Just a) = undefined f Nothing = undefined or 'doSomething >>= \(x::Either l r)->body' would become doSomething >>= \x->case x of {Left l->body; Right r->body} which, of course, should rather be doSomething >>= either (\l->body) (\r->body) yes, there are many opportunities for making haskell editing easier, and not all of them require detailed editor hacking or haskell analysis and transformation skills (though some do). keep the suggestions coming. perhaps summarize them on a haskell.org wiki page, though, so they don't get lost. someone might get round to implementing them, some of them might already be available!-) if someone were to put up a simple table/list of desired ide features (with brief descriptions) on the wiki, everyone could add links to each feature showing how their favourite ide handles said feature. then new users could go through that list and choose to learn one of those ides that provides most of the features they need. and fans of a particular ide could use the list to pick any missing feature that they feel able to implement.. claus