<div dir="ltr"><div>There has been discussion on the changes to the Prelude. Just found this (<a href="https://wiki.haskell.org/Foldable_Traversable_In_Prelude">https://wiki.haskell.org/Foldable_Traversable_In_Prelude</a>). <br><br></div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 12, 2015 at 7:57 PM, akash g <span dir="ltr"><<a href="mailto:akaberto@gmail.com" target="_blank">akaberto@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I think these changes came with GHC 7.10. I also completely agree that this is difficult for beginners. They should've had a beginner's Prelude or something :)<br><br><br></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 12, 2015 at 7:18 PM, Dennis Raddle <span dir="ltr"><<a href="mailto:dennis.raddle@gmail.com" target="_blank">dennis.raddle@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Speaking of lists and history, I noticed that a lot of library functions which were formerly defined over lists (when I first looked at Haskell six years ago) are now defined on Traversable, which makes it a lot harder for beginners to read the documentation. I have been playing with Haskell for five years, but not much, so I'm still a beginner. I just mentally substitute lists when I see Traversable. <div><br></div><div>I only really use lists and Maybe, as far as instances of the typeclasses go. That's only two types, but a lot to learn!</div><span><font color="#888888"><div><br></div><div>D</div><div><br></div><div><br></div><div><br></div></font></span></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 12, 2015 at 5:42 AM, akash g <span dir="ltr"><<a href="mailto:akaberto@gmail.com" target="_blank">akaberto@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><a href="http://stackoverflow.com/questions/7463500/why-do-we-have-map-fmap-and-liftm" target="_blank">http://stackoverflow.com/questions/7463500/why-do-we-have-map-fmap-and-liftm</a> have very good answers on this.<br></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 12, 2015 at 7:11 PM, akash g <span dir="ltr"><<a href="mailto:akaberto@gmail.com" target="_blank">akaberto@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">map is specialized for lists while fmap is for any functors. Its presence is historical. Prefer fmap over map.<br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Thu, Nov 12, 2015 at 7:03 PM, Dennis Raddle <span dir="ltr"><<a href="mailto:dennis.raddle@gmail.com" target="_blank">dennis.raddle@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr">Just after I posted that question, I started driving home, and on the drive I thought of your answer. I think I'm starting to ask the right questions when I'm programming in Haskell. Like redundancy and bloat is a sure sign that a more witty expression is available, and that I should consult the typeclasses. <div><br></div><div>Second, I am not used to the implications of laziness, so it took me a while to hit on your solution because I keep thinking you have to map something over the whole list, and that if you only want to map it over the head, you are stuck. </div><div><br></div><div>You can use 'map' also, instead of 'fmap', right? Is 'map' just 'fmap' for lists?</div><span><font color="#888888"><div><br></div><div>D</div><div><br></div></font></span></div>
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