[location] [ast] Switch Constrexpr AST to an extensible node type.

Following @gasche idea, and the original intention of #402, we switch
the main parsing AST of Coq from `'a Loc.located` to `'a CAst.ast`
which is private and record-based.

This provides significantly clearer code for the AST, and is robust
wrt attributes.

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/cAst.mli b/lib/cAst.mli
new file mode 100644
index 000000000..291536d12
--- /dev/null
+++ b/lib/cAst.mli
@@ -0,0 +1,22 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2017     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+(** The ast type contains generic metadata for AST nodes *)
+type 'a ast = private {
+  v   : 'a;
+  loc : Loc.t option;
+}
+
+val make : ?loc:Loc.t -> 'a -> 'a ast
+
+val map : ('a -> 'b) -> 'a ast -> 'b ast
+val map_with_loc : (?loc:Loc.t -> 'a -> 'b) -> 'a ast -> 'b ast
+val map_from_loc : (?loc:Loc.t -> 'a -> 'b) -> 'a Loc.located -> 'b ast
+
+val with_val : ('a -> 'b) -> 'a ast -> 'b
+val with_loc_val : (?loc:Loc.t -> 'a -> 'b) -> 'a ast -> 'b