<div dir="ltr">Hi.<br><div class="gmail_extra"><br><div class="gmail_quote">On 28 May 2013 18:07, Frerich Raabe <span dir="ltr"><<a href="mailto:raabe@froglogic.com" target="_blank">raabe@froglogic.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="im"><br>
On May 28, 2013, at 12:36 AM, harry <<a href="mailto:voldermort@hotmail.com">voldermort@hotmail.com</a>> wrote:<br>
<br>
> Every OO language which supports generics allows a declaration such as<br>
> List<Show> alist, where Show is an interface. Any type implementing Show can<br>
> be put in alist, and any Show operation can be performed on the alist's<br>
> members. No casts, wrappers, or other special types and plumbing are needed.<br>
><br>
> Why isn't it possible to do this directly in Haskell?<br>
<br>
</div>My impression is that you often don't have this requirement, since functions are first-class values and you can treat them as closures.<br></blockquote><div><br></div><div style>This might also be relevant: <a href="http://okmij.org/ftp/Computation/Existentials.html">http://okmij.org/ftp/Computation/Existentials.html</a></div>
<div style><br></div><div style>Hope this helps,</div><div style>Ozgur.</div><div style><br></div></div>
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