Re: [Haskell-beginners] can I use "pure" all the time instead of "return" now?

Typo, I wrote:

as in "non-monadic values are impure" meant of course as in "monadic values are impure"

Interesting interpretation! It might not be the one intended, but I always saw "pure" as meaning something like "input just wrapped" (echoing Maybe ofc), "input without effects", i think is the terminology. In other terms, to me "pure", there, is not an absolute description of the "type" of input (especially since the name of a function traditionally mostly defines the output, not the input), as in "non-monadic values are impure", but is a relative description visavis the input, aka, "the output is the undiluted, uneffectful monadic version of the input". Dunno if that was what you meant by "unadorned". In other terms "pure" makes me see the function as a sort of identity

Le dimanche 15 mai 2016, Silent Leaf a écrit : that does not dilute or otherwise modify the input value, solely "wraps" it (more or less metaphorically), makes it monadic without modification. I don't see it as meaning that its input values are of a purer "kind" than the corresponding outputs because those latter are (more) monadic. And we can feed monadic values to pure anyway.

As for echoing "purely functional language", well ... i don't really see

the link (but i might very well miss something), but at any rate isn't it true in the first place (Haskell being pure, barring uses of unsafeStuff/Foreign/etc)?

Le dimanche 15 mai 2016, Doug McIlroy a écrit :

...

...

the name [return] "stains" the functional semantics in Monadic code, in my opinion

Amusing. For me, the term "pure" stains monads as impure or diluted. The moral overtones of "pure", as in "purely functional language", drive out more benign interpretatations such as "unadorned". Not a felicitous coinage.

Doug McIlroy _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners