From a554519874c15d0a790082e5f15f3dc2419c6c38 Mon Sep 17 00:00:00 2001
From: Emilio Jesus Gallego Arias <e+git@x80.org>
Date: Sun, 19 Nov 2017 04:47:15 +0100
Subject: [lib] Minor pending cleanup to consolidate helper function.

While we are at it we refactor a few special cases of the helper.
---
 interp/constrextern.ml | 12 +-----------
 lib/flags.ml           | 34 +++++++++++-----------------------
 lib/flags.mli          |  9 +++++++++
 3 files changed, 21 insertions(+), 34 deletions(-)

diff --git a/interp/constrextern.ml b/interp/constrextern.ml
index e1cf8f196..0ce672cc8 100644
--- a/interp/constrextern.ml
+++ b/interp/constrextern.ml
@@ -185,18 +185,8 @@ let with_universes f = Flags.with_option print_universes f
 let with_meta_as_hole f = Flags.with_option print_meta_as_hole f
 let without_symbols f = Flags.with_option print_no_symbol f
 
-(* XXX: Where to put this in the library? Util maybe? *)
-let protect_ref r nf f x =
-  let old_ref = !r in
-  r := nf !r;
-  try let res = f x in r := old_ref; res
-  with reraise ->
-    let reraise = Backtrace.add_backtrace reraise in
-    r := old_ref;
-    Exninfo.iraise reraise
-
 let without_specific_symbols l =
-  protect_ref inactive_notations_table
+  Flags.with_modified_ref inactive_notations_table
     (fun tbl -> IRuleSet.(union (of_list l) tbl))
 
 (**********************************************************************)
diff --git a/lib/flags.ml b/lib/flags.ml
index 323b5492d..ddc8f8482 100644
--- a/lib/flags.ml
+++ b/lib/flags.ml
@@ -6,13 +6,17 @@
 (*         *       GNU Lesser General Public License Version 2.1        *)
 (************************************************************************)
 
-let with_option o f x =
-  let old = !o in o:=true;
-   try let r = f x in if !o = true then o := old; r
-   with reraise ->
-     let reraise = Backtrace.add_backtrace reraise in
-     let () = o := old in
-     Exninfo.iraise reraise
+let with_modified_ref r nf f x =
+  let old_ref = !r in r := nf !r;
+  try let res = f x in r := old_ref; res
+  with reraise ->
+    let reraise = Backtrace.add_backtrace reraise in
+    r := old_ref;
+    Exninfo.iraise reraise
+
+let with_option o f x = with_modified_ref o (fun _ -> true) f x
+let without_option o f x = with_modified_ref o (fun _ -> false) f x
+let with_extra_values o l f x = with_modified_ref o (fun ol -> ol@l) f x
 
 let with_options ol f x =
   let vl = List.map (!) ol in
@@ -25,22 +29,6 @@ let with_options ol f x =
     let () = List.iter2 (:=) ol vl in
     Exninfo.iraise reraise
 
-let without_option o f x =
-  let old = !o in o:=false;
-  try let r = f x in if !o = false then o := old; r
-  with reraise ->
-    let reraise = Backtrace.add_backtrace reraise in
-    let () = o := old in
-    Exninfo.iraise reraise
-
-let with_extra_values o l f x =
-  let old = !o in o:=old@l;
-  try let r = f x in o := old; r
-  with reraise ->
-    let reraise = Backtrace.add_backtrace reraise in
-    let () = o := old in
-    Exninfo.iraise reraise
-
 let boot = ref false
 
 let record_aux_file = ref false
diff --git a/lib/flags.mli b/lib/flags.mli
index 0ff3e0a81..c4afb8318 100644
--- a/lib/flags.mli
+++ b/lib/flags.mli
@@ -110,6 +110,15 @@ val warn : bool ref
 val make_warn : bool -> unit
 val if_warn : ('a -> unit) -> 'a -> unit
 
+(** [with_modified_ref r nf f x] Temporarily modify a reference in the
+    call to [f x] . Be very careful with these functions, it is very
+    easy to fall in the typical problem with effects:
+
+    with_modified_ref r nf f x y != with_modified_ref r nf (f x) y
+
+*)
+val with_modified_ref : 'c ref -> ('c -> 'c) -> ('a -> 'b) -> 'a -> 'b
+
 (** Temporarily activate an option (to activate option [o] on [f x y z],
    use [with_option o (f x y) z]) *)
 val with_option : bool ref -> ('a -> 'b) -> 'a -> 'b
-- 
cgit v1.2.3