Adding support for parsing subterms of a notation as "pattern".

This allows in particular to define notations with 'pat style binders.

E.g.:

A non-trivial change in this commit is storing binders and patterns
separately from terms.

This is not strictly necessary but has some advantages.

However, it is relatively common to have binders also used as terms,
or binders parsed as terms. Thus, it is already relatively common to
embed binders into terms (see e.g. notation for ETA in output test
Notations3.v) or to coerce terms to idents (see e.g. the notation for
{x|P} where x is parsed as a constr).

So, it is as simple to always store idents (and eventually patterns)
as terms.

2 files changed, 9 insertions, 0 deletions

diff --git a/test-suite/output/Notations3.out b/test-suite/output/Notations3.out
index 5bb77b8fd..fb2d375c2 100644
--- a/test-suite/output/Notations3.out
+++ b/test-suite/output/Notations3.out
@@ -195,3 +195,5 @@ fun x : nat => if x is n .+ 1 then n else 1
      : nat -> nat
 {{{x, y}} : nat * nat | x + y = 0}
      : Set
+exists2' {{x, y}}, x = 0 & y = 0
+     : Prop
diff --git a/test-suite/output/Notations3.v b/test-suite/output/Notations3.v
index 201198b3e..46e0c1b1b 100644
--- a/test-suite/output/Notations3.v
+++ b/test-suite/output/Notations3.v
@@ -337,3 +337,10 @@ Check fun x => if x is n.+1 then n else 1.
 (* Examples with binding patterns *)
 
 Check {(x,y)|x+y=0}.
+
+Notation "'exists2'' x , p & q" := (ex2 (fun x => p) (fun x => q))
+  (at level 200, x pattern, p at level 200, right associativity,
+    format "'[' 'exists2''  '/  ' x ,  '/  ' '[' p  &  '/' q ']' ']'")
+  : type_scope.
+
+Check exists2' (x,y), x=0 & y=0.