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| author |  Adam Chlipala <adam@chlipala.net> | 2013-11-03 19:27:30 -0500 |
|---|---|---|
| committer | Adam Chlipala <adam@chlipala.net> | 2013-11-03 19:27:30 -0500 |
| commit | d2196dbd5c4379bdbc307d2035c8a07ef09b592d (patch) | |
| tree | 03de0d970495a013a2e126010600137ebb5746dd | |
| parent | 65b818146effe2f74192a3b1d65b4ec792a8a350 (diff) | |
ListPair.map2, based on code by escalier@riseup.net
| -rw-r--r-- | lib/ur/listPair.ur | 11 | ||||
| -rw-r--r-- | lib/ur/listPair.urs | 3 | ||||
| -rw-r--r-- | tests/listpair.ur | 6 | ||||
| -rw-r--r-- | tests/listpair.urp | 5 |
4 files changed, 25 insertions, 0 deletions
diff --git a/lib/ur/listPair.ur b/lib/ur/listPair.ur index 0182af19..d69993f9 100644 --- a/lib/ur/listPair.ur +++ b/lib/ur/listPair.ur @@ -33,3 +33,14 @@ fun all [a] [b] f = in all' end + +fun map2 [a] [b] [c] (f : a -> b -> c) = + let + fun map2' ls1 ls2 = + case (ls1, ls2) of + ([], []) => [] + | (x1 :: ls1, x2 :: ls2) => f x1 x2 :: map2' ls1 ls2 + | _ => error <xml>ListPair.map2: Unequal list lengths</xml> + in + map2' + end diff --git a/lib/ur/listPair.urs b/lib/ur/listPair.urs index f2287c13..218b9420 100644 --- a/lib/ur/listPair.urs +++ b/lib/ur/listPair.urs @@ -5,3 +5,6 @@ val mapX : a ::: Type -> b ::: Type -> ctx ::: {Unit} -> (a -> b -> xml ctx [] []) -> list a -> list b -> xml ctx [] [] val all : a ::: Type -> b ::: Type -> (a -> b -> bool) -> list a -> list b -> bool + +val map2 : a ::: Type -> b ::: Type -> c ::: Type + -> (a -> b -> c) -> list a -> list b -> list c diff --git a/tests/listpair.ur b/tests/listpair.ur new file mode 100644 index 00000000..4ecacfd3 --- /dev/null +++ b/tests/listpair.ur @@ -0,0 +1,6 @@ +val x = 1 :: 2 :: [] +val y = 3 :: 4 :: [] + +fun main () : transaction page = return <xml> + {[ListPair.map2 plus x y]} +</xml> diff --git a/tests/listpair.urp b/tests/listpair.urp new file mode 100644 index 00000000..1b447ed6 --- /dev/null +++ b/tests/listpair.urp @@ -0,0 +1,5 @@ +rewrite all Listpair/* + +$/list +$/listPair +listpair |