[Haskell-beginners] Are these soloutions all valid and a good use of Haskell

[Chris Linton-Ford]

Never mind - I should have Googled this: https://www.haskell.org/haskellwiki/Haskell_programming_tips#Avoid_explicit_recursion

Chris


-----Original Message-----
From: Beginners [mailto:beginners-bounces at haskell.org] On Behalf Of Chris Linton-Ford
Sent: Monday, November 10, 2014 10:25 AM
To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell
Subject: Re: [Haskell-beginners] Are these soloutions all valid and a good use of Haskell

I've seen this mentioned a couple of times - that you should avoid explicit recursion where possible in Haskell (although I can't find the references now).

Is this to make programs easier to understand, or more compact, or is there a performance benefit?

Chris



-----Original Message-----
From: Beginners [mailto:beginners-bounces at haskell.org] On Behalf Of Karl Voelker
Sent: Monday, November 10, 2014 10:17 AM
To: beginners at haskell.org
Subject: Re: [Haskell-beginners] Are these soloutions all valid and a good use of Haskell

On Mon, Nov 10, 2014, at 01:50 AM, Roelof Wobben wrote:
> What do you experts think of the different ways ?

2 and 4 are quite similar, and both fine. 3 is not so good: guards provide weaker guarantees than patterns, and head and tail are partial functions.

All three implementations have in common that they do their own recursion. It would be a good exercise to try implementing last as a fold - in other words, letting the standard library do the recursion for you.

-Karl
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