Hi,<br><br><div class="gmail_quote">2011/2/10 Yitzchak Gale <span dir="ltr"><<a href="mailto:gale@sefer.org">gale@sefer.org</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Simon Peyton-Jones wrote:<br>
> "Generic Defaults"... will replace... the "Derivable type classes"<br>
> stuff... in GHC 7.2 or 7.4...<br>
<div class="im">> Please yell if you are a secret user of derivable type classes,<br>
> so this change would discombobulate you.<br>
<br>
</div>Could you give us a preview of the parts of the syntax<br>
spectrum that will be gobbled up by this? That is a way<br>
that the change could affect even people who are not using<br>
the current generics.<br></blockquote><div><br>As far as I understand, only the keyword "generic" will be taken. A new GHC.Generics module will define many new types with common names like `C` and `D`; these are used for the generic representation of datatypes in any module that enables -XGenerics, but there are no clashes unless the programmer explicitly imports GHC.Generics, so that should be ok.<br>
</div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<br>
For example, the old generics knocked a very nice bracket<br>
out of consideration for TH syntax. It also blessed the names<br>
of certain magical constructors, which can be good to know<br>
about even if the magic doesn't leak out of the generics world.<br></blockquote><div><br>I remember there was some strange behavior with a type constructor `1` which was supposedly caused by the old generics (or was it syb?). Hopefully there will be nothing like that in the new mechanism.<br>
<br><br>Cheers,<br>Pedro<br> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<br>
Thanks,<br>
Yitz<br>
</blockquote></div><br>