A "map" can be a function (applied to a (single) value). Got it.
Thanks, Michael --- On Fri, 8/27/10, Ivan Lazar Miljenovic <ivan.miljeno...@gmail.com> wrote: From: Ivan Lazar Miljenovic <ivan.miljeno...@gmail.com> Subject: Re: [Haskell-cafe] On to applicative To: "michael rice" <nowg...@yahoo.com> Cc: haskell-cafe@haskell.org Date: Friday, August 27, 2010, 8:46 PM On 28 August 2010 10:38, michael rice <nowg...@yahoo.com> wrote: > > fmap seems oddly named because no "mapping" takes place, except in the fourth > example, where the map is "passed in." Just sayin'. *ahem* http://en.wikipedia.org/wiki/Map_%28mathematics%29 > Prelude Control.Monad Control.Applicative Data.Char> fmap toUpper getLine > > <interactive>:1:13: > Couldn't match expected type `Char' against inferred type `[Char]' > Expected type: IO Char > Inferred type: IO String > In the second argument of `fmap', namely `getLine' > In the expression: fmap toUpper getLine Right; this is because the fmap only gets the "Char -> Char" function inside the IO; but since it's "IO String" rather than "IO Char", this doesn't type-check. -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com
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