Never mind - I should have Googled this: https://www.haskell.org/haskellwiki/Haskell_programming_tips#Avoid_explicit_... Chris -----Original Message----- From: Beginners [mailto:beginners-bounces@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@haskell.org] On Behalf Of Karl Voelker Sent: Monday, November 10, 2014 10:17 AM To: beginners@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 _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners KCG Europe Limited is authorized and regulated by the Financial Conduct Authority. Registered Office 55 Basinghall Street, London, EC2V 5DU. Registered in England & Wales No. 03632121 This e-mail and its attachments are intended only for the individual or entity to whom it is addressed and may contain information that is confidential, privileged, inside information, or subject to other restrictions on use or disclosure. Any unauthorized use, dissemination or copying of this transmission or the information in it is prohibited and may be unlawful. If you have received this transmission in error, please notify the sender immediately by return e-mail, and permanently delete or destroy this e-mail, any attachments, and all copies (digital or paper). Unless expressly stated in this e-mail, nothing in this message should be construed as a digital or electronic signature. For additional important disclaimers and disclosures regarding KCG’s products and services, please click on the following link: http://www.kcg.com/legal/global-disclosures _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners KCG Europe Limited is authorized and regulated by the Financial Conduct Authority. Registered Office 55 Basinghall Street, London, EC2V 5DU. Registered in England & Wales No. 03632121 This e-mail and its attachments are intended only for the individual or entity to whom it is addressed and may contain information that is confidential, privileged, inside information, or subject to other restrictions on use or disclosure. Any unauthorized use, dissemination or copying of this transmission or the information in it is prohibited and may be unlawful. If you have received this transmission in error, please notify the sender immediately by return e-mail, and permanently delete or destroy this e-mail, any attachments, and all copies (digital or paper). Unless expressly stated in this e-mail, nothing in this message should be construed as a digital or electronic signature. For additional important disclaimers and disclosures regarding KCG’s products and services, please click on the following link: http://www.kcg.com/legal/global-disclosures