# HG changeset patch
# User Adam Chlipala <adam@chlipala.net>
# Date 1296760922 18000
# Node ID 67b33be5d56afa424d1c467b32e84dc8cc4dcff5
# Parent  763eb2f2aa5ae59aee4ac1202e9ad97f773c11ea
Record.numFields

diff -r 763eb2f2aa5a -r 67b33be5d56a record.ur
--- a/record.ur	Thu Feb 03 09:31:32 2011 -0500
+++ b/record.ur	Thu Feb 03 14:22:02 2011 -0500
@@ -1,3 +1,6 @@
+fun numFields [r ::: {Type}] (fl : folder r) (r : $r) : int =
+    @fold [fn _ => int] (fn [nm ::_] [u ::_] [r ::_] [[nm] ~ r] acc => acc+1) 0 fl
+
 fun mem [a ::: Type] [ns ::: {Unit}] (_ : eq a) (fl : folder ns) (x : a) (r : $(mapU a ns)) : bool =
     @foldUR [a] [fn _ => bool]
      (fn [nm ::_] [r ::_] [[nm] ~ r] y acc =>
diff -r 763eb2f2aa5a -r 67b33be5d56a record.urs
--- a/record.urs	Thu Feb 03 09:31:32 2011 -0500
+++ b/record.urs	Thu Feb 03 14:22:02 2011 -0500
@@ -1,2 +1,4 @@
+val numFields : r ::: {Type} -> folder r -> $r -> int
+
 val mem : a ::: Type -> ns ::: {Unit} -> eq a -> folder ns -> a -> $(mapU a ns) -> bool
 (* Is a value found in a record? *)