Mercurial > urweb
view demo/tcSum.ur @ 1795:d28adceef22a
Allow type class instances with hypotheses via local ('let') definitions
author | Adam Chlipala <adam@chlipala.net> |
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date | Wed, 25 Jul 2012 14:04:59 -0400 |
parents | 8d3aa6c7cee0 |
children |
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fun sum [t] (_ : num t) [fs ::: {Unit}] (fl : folder fs) (x : $(mapU t fs)) = @foldUR [t] [fn _ => t] (fn [nm :: Name] [rest :: {Unit}] [[nm] ~ rest] n acc => n + acc) zero fl x fun main () = return <xml><body> {[sum {A = 0, B = 1}]}<br/> {[sum {C = 2.1, D = 3.2, E = 4.3}]} </body></xml>