view demo/sum.ur @ 1887:2e6795cc992f

A fancier test for the new SQL constraints subtyping
author Adam Chlipala <adam@chlipala.net>
date Mon, 04 Nov 2013 16:00:48 -0500
parents 8d3aa6c7cee0
children
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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>