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view demo/sum.ur @ 1228:7dfa67560916

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Using multiple policies to check a written value
author Adam Chlipala <adamc@hcoop.net>
date Sun, 11 Apr 2010 16:46:38 -0400
parents 8d3aa6c7cee0
children
line wrap: on
line source
fun sum [fs ::: {Unit}] (fl : folder fs) (x : $(mapU int fs)) =
    @foldUR [int] [fn _ => int]
     (fn [nm :: Name] [rest :: {Unit}] [[nm] ~ rest] n acc => n + acc)
     0 fl x

fun main () = return <xml><body>
  {[sum {}]}<br/>
  {[sum {A = 0, B = 1}]}<br/>
  {[sum {C = 2, D = 3, E = 4}]}
</body></xml>