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Date: Wed, 19 Sep 2012 16:08:54 +0100
From: Alan Burlison <alan.burli...@gmail.com>
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To: missingfaktor <rahul.phulore....@gmail.com>
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Subject: Re: [scala-user] <:< versus HKT
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On 19/09/2012 13:10, missingfaktor wrote:

> This thread might help too.
> https://groups.google.com/forum/#!topic/scala-user/s38hv6culCw

A bit.  I'm still not 100% clear when you *must* use implicit evidence 
parameters because nothing else will work.  For example, in the toMap 
example, if you need the supplied list to consist of 2-tuples, why can't 
you just say that directly using the Tuple2 type?

In the example you give in the thread 
(https://groups.google.com/d/msg/scala-user/s38hv6culCw/ssVM5X0ewbMJ) I 
can see that you are using 'implicit ev: A =:= Int' to in effect defer 
the check that A is an Int until that method is actually used.

However, I'm not clear in the toMap case why implicit evidence 
parameters are necessary and a use of Tuple2 won't work, although I'm 
struggling to come up with something that the Scala compiler actually likes.

Thanks for the link though, it did help some :-)

-- 
Alan Burlison
--