From 41cd154483d45c5d2fb0abf392b9bdc63d42b94e Mon Sep 17 00:00:00 2001
From: Adam Chlipala <adamc@csail.mit.edu>
Date: Wed, 25 Jan 2017 15:55:14 -0500
Subject: List.appi

---
 lib/ur/list.ur  | 12 ++++++++++++
 lib/ur/list.urs |  3 +++
 2 files changed, 15 insertions(+)

(limited to 'lib')

diff --git a/lib/ur/list.ur b/lib/ur/list.ur
index 50764e46..cc533676 100644
--- a/lib/ur/list.ur
+++ b/lib/ur/list.ur
@@ -311,6 +311,18 @@ fun app [m] (_ : monad m) [a] f =
         app'
     end
 
+fun appi [m] (_ : monad m) [a] f =
+    let
+        fun app' i ls =
+            case ls of
+                [] => return ()
+              | x :: ls =>
+                f i x;
+                app' (i + 1) ls
+    in
+        app' 0
+    end
+
 fun mapQuery [tables ::: {{Type}}] [exps ::: {Type}] [t ::: Type]
              [tables ~ exps] (q : sql_query [] [] tables exps)
              (f : $(exps ++ map (fn fields :: {Type} => $fields) tables) -> t) =
diff --git a/lib/ur/list.urs b/lib/ur/list.urs
index 432d8c1a..fd56679d 100644
--- a/lib/ur/list.urs
+++ b/lib/ur/list.urs
@@ -65,6 +65,9 @@ val all : a ::: Type -> (a -> bool) -> t a -> bool
 val app : m ::: (Type -> Type) -> monad m -> a ::: Type
           -> (a -> m unit) -> t a -> m unit
 
+val appi : m ::: (Type -> Type) -> monad m -> a ::: Type
+           -> (int -> a -> m unit) -> t a -> m unit
+
 val tabulateM : m ::: (Type -> Type) -> monad m -> a ::: Type
                 -> (int -> m a) -> int -> m (t a)
 
-- 
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