Integrate build and documentation of Ltac2

Since Ltac2 cannot be put under the stdlib logical root (some file names
would clash), we move it to the `user-contrib` directory, to avoid adding
another hardcoded path in `coqinit.ml`, following a suggestion by @ejgallego.

Thanks to @Zimmi48 for the thorough documentation review and the
numerous suggestions.

1 files changed, 102 insertions, 0 deletions

diff --git a/user-contrib/Ltac2/tac2quote.mli b/user-contrib/Ltac2/tac2quote.mli
new file mode 100644
index 0000000000..1b03dad8ec
--- /dev/null
+++ b/user-contrib/Ltac2/tac2quote.mli
@@ -0,0 +1,102 @@
+(************************************************************************)
+(*  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        *)
+(************************************************************************)
+
+open Names
+open Tac2dyn
+open Tac2qexpr
+open Tac2expr
+
+(** Syntactic quoting of expressions. *)
+
+(** Contrarily to Tac2ffi, which lives on the semantic level, this module
+    manipulates pure syntax of Ltac2. Its main purpose is to write notations. *)
+
+val constructor : ?loc:Loc.t -> ltac_constructor -> raw_tacexpr list -> raw_tacexpr
+
+val thunk : raw_tacexpr -> raw_tacexpr
+
+val of_anti : ('a -> raw_tacexpr) -> 'a or_anti -> raw_tacexpr
+
+val of_int : int CAst.t -> raw_tacexpr
+
+val of_pair : ('a -> raw_tacexpr) -> ('b -> raw_tacexpr) -> ('a * 'b) CAst.t -> raw_tacexpr
+
+val of_tuple : ?loc:Loc.t -> raw_tacexpr list -> raw_tacexpr
+
+val of_variable : Id.t CAst.t -> raw_tacexpr
+
+val of_ident : Id.t CAst.t -> raw_tacexpr
+
+val of_constr : Constrexpr.constr_expr -> raw_tacexpr
+
+val of_open_constr : Constrexpr.constr_expr -> raw_tacexpr
+
+val of_list : ?loc:Loc.t -> ('a -> raw_tacexpr) -> 'a list -> raw_tacexpr
+
+val of_bindings : bindings -> raw_tacexpr
+
+val of_intro_pattern : intro_pattern -> raw_tacexpr
+
+val of_intro_patterns : intro_pattern list CAst.t -> raw_tacexpr
+
+val of_clause : clause -> raw_tacexpr
+
+val of_destruction_arg : destruction_arg -> raw_tacexpr
+
+val of_induction_clause : induction_clause -> raw_tacexpr
+
+val of_conversion : conversion -> raw_tacexpr
+
+val of_rewriting : rewriting -> raw_tacexpr
+
+val of_occurrences : occurrences -> raw_tacexpr
+
+val of_hintdb : hintdb -> raw_tacexpr
+
+val of_move_location : move_location -> raw_tacexpr
+
+val of_reference : reference or_anti -> raw_tacexpr
+
+val of_hyp : ?loc:Loc.t -> Id.t CAst.t -> raw_tacexpr
+(** id ↦ 'Control.hyp @id' *)
+
+val of_exact_hyp : ?loc:Loc.t -> Id.t CAst.t -> raw_tacexpr
+(** id ↦ 'Control.refine (fun () => Control.hyp @id') *)
+
+val of_exact_var : ?loc:Loc.t -> Id.t CAst.t -> raw_tacexpr
+(** id ↦ 'Control.refine (fun () => Control.hyp @id') *)
+
+val of_dispatch : dispatch -> raw_tacexpr
+
+val of_strategy_flag : strategy_flag -> raw_tacexpr
+
+val of_pose : pose -> raw_tacexpr
+
+val of_assertion : assertion -> raw_tacexpr
+
+val of_constr_matching : constr_matching -> raw_tacexpr
+
+val of_goal_matching : goal_matching -> raw_tacexpr
+
+(** {5 Generic arguments} *)
+
+val wit_pattern : (Constrexpr.constr_expr, Pattern.constr_pattern) Arg.tag
+
+val wit_ident : (Id.t, Id.t) Arg.tag
+
+val wit_reference : (reference, GlobRef.t) Arg.tag
+
+val wit_constr : (Constrexpr.constr_expr, Glob_term.glob_constr) Arg.tag
+
+val wit_open_constr : (Constrexpr.constr_expr, Glob_term.glob_constr) Arg.tag
+
+val wit_ltac1 : (Ltac_plugin.Tacexpr.raw_tactic_expr, Ltac_plugin.Tacexpr.glob_tactic_expr) Arg.tag
+(** Ltac1 AST quotation, seen as a 'tactic'. Its type is unit in Ltac2. *)
+
+val wit_ltac1val : (Ltac_plugin.Tacexpr.raw_tactic_expr, Ltac_plugin.Tacexpr.glob_tactic_expr) Arg.tag
+(** Ltac1 AST quotation, seen as a value-returning expression, with type Ltac1.t. *)