farginay on Making Map Operations Implicit in Programming

Comment on Making Map Operations Implicit in Programming parent

I think the big thing is to make the case for one and the case for many look exactly the same in the language. Is that nicer to look at with do-notation?

DanWaterworth 12y

With do notation, it becomes:

    do
      n <- name
      let trimmed = trim n
      guard (length trimmed /= 0)
      return (toUpperCase trimmed)

farginayOP12y

Wouldn't it be nice if it was just:

    toUpperCase . guard (\x -> length x /= 0) . trim

I think that is how it would be if it was part of the language.

DanWaterworth 12y

I like my code to do what it says. You can pretty much do that in Haskell. If you allow me to add a definition first:

    mfilter' :: MonadPlus m => (a -> Bool) -> a -> m a
    mfilter' f = mfilter f . return

Then it's just:

    toUpperCase <=< mfilter' (\x -> length x /= 0) . trim

Which is pretty close. No need to change the language.

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