diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/flags.ml | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/lib/flags.ml b/lib/flags.ml index ee4c0734a..01361dad5 100644 --- a/lib/flags.ml +++ b/lib/flags.ml @@ -6,18 +6,28 @@ (* * GNU Lesser General Public License Version 2.1 *) (************************************************************************) -let with_modified_ref r nf f x = +(* If [restore] is false, whenever [f] modifies the ref, we will + preserve the modification. *) +let with_modified_ref ?(restore=true) r nf f x = let old_ref = !r in r := nf !r; - try let res = f x in r := old_ref; res + try + let pre = !r in + let res = f x in + (* If r was modified don't restore its old value *) + if restore || pre == !r then 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_option o f x = with_modified_ref ~restore:false o (fun _ -> true) f x +let without_option o f x = with_modified_ref ~restore:false o (fun _ -> false) f x let with_extra_values o l f x = with_modified_ref o (fun ol -> ol@l) f x +(* hide the [restore] option as internal *) +let with_modified_ref r nf f x = with_modified_ref r nf f x + let with_options ol f x = let vl = List.map (!) ol in let () = List.iter (fun r -> r := true) ol in |