annotate demo/sum.ur @ 637:24fd1edfcaa3

Kind-polymorphic [fst] and friends
author Adam Chlipala <adamc@hcoop.net>
date Thu, 26 Feb 2009 16:16:54 -0500
parents 03ab853c8e4b
children aa2290c32ce2
rev   line source
adamc@632 1 fun sum (fs ::: {Unit}) (fl : folder fs) (x : $(mapUT int fs)) =
adamc@411 2 foldUR [int] [fn _ => int]
adamc@411 3 (fn (nm :: Name) (rest :: {Unit}) [[nm] ~ rest] n acc => n + acc)
adamc@632 4 0 [fs] fl x
adamc@411 5
adamc@411 6 fun main () = return <xml><body>
adamc@633 7 {[sum {}]}<br/>
adamc@633 8 {[sum {A = 0, B = 1}]}<br/>
adamc@633 9 {[sum {C = 2, D = 3, E = 4}]}
adamc@411 10 </body></xml>