view demo/tcSum.ur @ 1187:ad9829c3c12c

COUNT(col)
author Adam Chlipala <adamc@hcoop.net>
date Tue, 16 Mar 2010 15:54:35 -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>