Adding necessary primitives to do pattern-matching over constr.

1 files changed, 30 insertions, 0 deletions

diff --git a/theories/Pattern.v b/theories/Pattern.v
new file mode 100644
index 0000000000..c2ba4162e8
--- /dev/null
+++ b/theories/Pattern.v
@@ -0,0 +1,30 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2016     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+Require Import Ltac2.Init.
+
+Ltac2 Type t := pattern.
+
+Ltac2 Type context.
+
+Ltac2 @ external matches : t -> constr -> (ident * constr) list :=
+  "ltac2" "pattern_matches".
+(** If the term matches the pattern, returns the bound variables. If it doesn't,
+    fail with [Match_failure]. Panics if not focussed. *)
+
+Ltac2 @ external matches_subterm : t -> constr -> context * ((ident * constr) list) :=
+  "ltac2" "pattern_matches_subterm".
+(** Returns a stream of results corresponding to all of the subterms of the term
+    that matches the pattern as in [matches]. The stream is encoded as a
+    backtracking value whose last exception is [Match_failure]. The additional
+    value compared to [matches] is the context of the match, to be filled with
+    the instantiate function. *)
+
+Ltac2 @ external instantiate : context -> constr -> constr :=
+  "ltac2" "pattern_instantiate".
+(** Fill the hole of a context with the given term. *)