Proposal: flipped fmap in base (again)

Francesco Ariis fa-ml at
Sat Feb 18 09:47:04 UTC 2017

On Fri, Feb 17, 2017 at 08:40:00PM -0800, Siddhanathan Shanmugam wrote:
> This was proposed about 7 years ago, and rejected at the time:

>From that ticket

> I'm not in favor of this proposal. Naming trivial compositions puts
> a complexity tax on all users of the library and we end up with 2*n
> operators instead of n operators and one flip function. It's trivial
> to define the function locally or in a helper module.
> To elaborate: At work some of our core APIs have gotten dramatically
> more complex due to their maintainers allowing people, in interest to
> keep their own code cleaner, to add small helper functions to those
> APIs. This is now recognized as bad practice and discouraged with a
> call to "not fear the semicolon"! (We use mostly imperative languages
> at work.)

(by Johan Tibell)

Those arguments seems to me as compelling today as they were 7 years
ago, what has changed meanwhile?

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