Fix top-level group elimination in ppx_regexp.

Author: paurkedal

ppx_regexp/ppx_regexp.ml

@@ -93,7 +93,11 @@ module Regexp = struct
        | Capture_as (_, e) -> "(" ^ recurse p_alt e ^ ")"
        | Call _ -> error ~loc "(&...) is not implemented for %pcre.")
     in
-    recurse 0
+    (function
+     | {Location.txt = Capture_as (_, e); _} ->
+        recurse 0 e
+     | e ->
+        recurse 0 e)
 end
 
 let dyn_bindings = ref []

tests/test_ppx_regexp.ml

@@ -61,6 +61,11 @@ let test3 s =
    | {|m(o+)re re(gular)? no(is)e, (no )*be(t+)?er|} -> ()
    | s' -> assert (s = s'))
 
+let test4 = function%pcre (* Issue 8 *)
+ | {|(?<x>[-+]?[[:digit:]]+.[[:digit:]]*)|} -> [x]
+ | {|(?<x>(abc))[[:space:]]*(?<y>(xyz))|} -> [x; y]
+ | _ -> assert false
+
 let () =
   test2 "<>";
   test2 "<a>";
@@ -74,7 +79,9 @@ let () =
   test2 "one";
   test2 "two";
   test3 "- + &nbsp; + -";
-  test3 "catch-all"
+  test3 "catch-all";
+  assert (test4 "::123.456::" = ["123.456"]);
+  assert (test4 "::abc xyz::" = ["abc"; "xyz"])
 
 (* It should work in a functor, and Re_pcre.regxp should be lifted to the
  * top-level. *)