From 96d6ef7036e19bf1def1512abae5ef8c6ace06b0 Mon Sep 17 00:00:00 2001
From: Hugo Herbelin
Date: Mon, 14 Aug 2017 13:29:39 +0200
Subject: Supporting recursive notations reversing the left-to-right order.

Seizing this opportunity to generalize the possibility for different
associativity into simply reversing the order or not. Also dropping
some dead code.

Example of recursive notation now working:

  Notation "[ a , .. , b |- A ]" := (cons b .. (cons a nil) .., A).
---
 test-suite/output/Notations.out  |  2 +-
 test-suite/output/Notations3.out | 18 ++++++++++++++++++
 test-suite/output/Notations3.v   | 19 +++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

(limited to 'test-suite')

diff --git a/test-suite/output/Notations.out b/test-suite/output/Notations.out
index 2f0ee765db..891296b0a1 100644
--- a/test-suite/output/Notations.out
+++ b/test-suite/output/Notations.out
@@ -41,7 +41,7 @@ fun x : nat => ifn x is succ n then n else 0
 -4
      : Z
 The command has indeed failed with message:
-x should not be bound in a recursive pattern of the right-hand side.
+Cannot find where the recursive pattern starts.
 The command has indeed failed with message:
 in the right-hand side, y and z should appear in
 term position as part of a recursive pattern.
diff --git a/test-suite/output/Notations3.out b/test-suite/output/Notations3.out
index 5bfdec9898..58dabe51e5 100644
--- a/test-suite/output/Notations3.out
+++ b/test-suite/output/Notations3.out
@@ -173,3 +173,21 @@ exists_true (x : nat) (A : Type) (R : A -> A -> Prop)
      : Prop * Prop
 exists_non_null x y z t : nat , x = y /\ z = t
      : Prop
+{{RL 1, 2}}
+     : nat * (nat * nat)
+{{RR 1, 2}}
+     : nat * nat * nat
+@pair nat (prod nat nat) (S (S O)) (@pair nat nat (S O) O)
+     : prod nat (prod nat nat)
+@pair (prod nat nat) nat (@pair nat nat O (S (S O))) (S O)
+     : prod (prod nat nat) nat
+{{RLRR 1, 2}}
+     : nat * (nat * nat) * (nat * nat * nat) * (nat * (nat * nat)) *
+       (nat * nat * nat)
+pair
+  (pair
+     (pair (pair (S (S O)) (pair (S O) O)) (pair (pair O (S (S O))) (S O)))
+     (pair (S O) (pair (S (S O)) O))) (pair (pair O (S O)) (S (S O)))
+     : prod
+         (prod (prod (prod nat (prod nat nat)) (prod (prod nat nat) nat))
+            (prod nat (prod nat nat))) (prod (prod nat nat) nat)
diff --git a/test-suite/output/Notations3.v b/test-suite/output/Notations3.v
index c7e32f733a..fd5846e71c 100644
--- a/test-suite/output/Notations3.v
+++ b/test-suite/output/Notations3.v
@@ -307,3 +307,22 @@ Notation "'exists_non_null' x .. y  , P" :=
   (ex (fun x => x <> 0 /\ .. (ex (fun y => y <> 0 /\ P)) ..))
   (at level 200, x binder).
 Check exists_non_null x y z t , x=y/\z=t.
+
+(* Examples where the recursive pattern is in reverse order *)
+
+Notation "{{RL  c , .. , d }}" := (pair d .. (pair c 0) ..).
+Check {{RL 1 , 2}}.
+
+Notation "{{RR  c , .. , d }}" := (pair .. (pair 0 d) .. c).
+Check {{RR 1 , 2}}.
+
+Set Printing All.
+Check {{RL 1 , 2}}.
+Check {{RR 1 , 2}}.
+Unset Printing All.
+
+Notation "{{RLRR  c , .. , d }}" := (pair d .. (pair c 0) .., pair .. (pair 0 d) .. c, pair c .. (pair d 0) .., pair .. (pair 0 c) .. d).
+Check {{RLRR 1 , 2}}.
+Unset Printing Notations.
+Check {{RLRR 1 , 2}}.
+Set Printing Notations.
-- 
cgit v1.2.3