[Haskell-cafe] programming style...and type classes...

Nicholls, Mark nicholls.mark at vimn.com
Fri Nov 4 08:31:55 UTC 2016

i like the example

but you say yourself it just means that bar2 should be elsewhere.::?

ie an oo'er would just say youve created the wrong abstraction, but not....dont create the abstraction....creating the abstraction is the mantra oo'ers are stylistically indoctonated in, in the name of extensibility (for good or evil)

so...is the problem with type classes that this modelling process is quite subtle and advanced? and thus should be avoided until you know what you're doing?
or something more?

(maybe the cost of the modelling process outweighs the benefit? even when you do know what youre doing?)

Excuse the spelling, sent from a phone with itty bitty keys, it like trying to sow a button on a shirt with a sausage.

On 3 Nov 2016, at 20:20, Brandon Allbery <allbery.b at gmail.com<mailto:allbery.b at gmail.com>> wrote:

On Thu, Nov 3, 2016 at 4:47 AM, Nicholls, Mark <nicholls.mark at vimn.com<mailto:nicholls.mark at vimn.com>> wrote:
i believe there is advice to avoid typeclasses stylistically? (see haskell wiki on style, allegedly because it leads to creeping haskell extensions...overlapping instances etc)...which lead you into the "wild" (allegedly SPJ)

Typeclasses are great when used properly and for their intended purpose. There is a tendency for new Haskellers to overuse them, or to mistake them for OOP classes and try to use them as such (which won't work, but *will* cause the compiler to start suggesting increasingly-far-afield extensions as it tries to make sense of what the programmer was trying to do).

brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com<mailto:allbery.b at gmail.com>                                  ballbery at sinenomine.net<mailto:ballbery at sinenomine.net>
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net

This e-mail (and any attached files) is confidential and protected by copyright (and other intellectual property rights). If you are not the intended recipient please e-mail the sender and then delete the email and any attached files immediately. Any further use or dissemination is prohibited.

While MTV Networks Europe has taken steps to ensure that this email and any attachments are virus free, it is your responsibility to ensure that this message and any attachments are virus free and do not affect your systems / data.

Communicating by email is not 100% secure and carries risks such as delay, data corruption, non-delivery, wrongful interception and unauthorised amendment. If you communicate with us by e-mail, you acknowledge and assume these risks, and you agree to take appropriate measures to minimise these risks when e-mailing us.

MTV Networks International, MTV Networks UK & Ireland, Greenhouse, Nickelodeon Viacom Consumer Products, VBSi, Viacom Brand Solutions International, Be Viacom, Viacom International Media Networks and VIMN and Comedy Central are all trading names of MTV Networks Europe.  MTV Networks Europe is a partnership between MTV Networks Europe Inc. and Viacom Networks Europe Inc.  Address for service in Great Britain is 17-29 Hawley Crescent, London, NW1 8TT.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/haskell-cafe/attachments/20161104/8f9b045e/attachment.html>

More information about the Haskell-Cafe mailing list