you are applying the type to lookup only!<br><br>try let lookupIn = ((flip lookup ) :: (Eq a) => [(a, b)] -> a -> Maybe b )<br><br><div class="gmail_quote">On Fri, Feb 20, 2009 at 07:27, Matt R <span dir="ltr"><<a href="mailto:mattrussell324@googlemail.com">mattrussell324@googlemail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">So what's this all about then? How come a has become ()?<br>
<br>
ghci> :t lookup<br>
lookup :: (Eq a) => a -> [(a, b)] -> Maybe b<br>
ghci> :t flip lookup<br>
flip lookup :: (Eq a) => [(a, b)] -> a -> Maybe b<br>
ghci> let lookupIn = (flip lookup :: (Eq a) => [(a, b)] -> a -> Maybe b )<br>
ghci> :t lookupIn<br>
lookupIn :: [((), b)] -> () -> Maybe b<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Rafael Gustavo da Cunha Pereira Pinto<br>Electronic Engineer, MSc.<br>