(regex_compile): Remove the `regnum' counter.

Use bufp->re_nsub instead.  Add support for \(?N:RE\).

1 files changed, 9 insertions, 0 deletions

diff --git a/lispref/searching.texi b/lispref/searching.texi
index 10e8c672962..f923a58f112 100644
--- a/lispref/searching.texi
+++ b/lispref/searching.texi
@@ -650,6 +650,15 @@ Shy groups are particularly useful for mechanically-constructed regular
 expressions because they can be added automatically without altering the
 numbering of any ordinary, non-shy groups.
 
+@item \(?@var{num}: @dots{} \)
+is the @dfn{explicitly numbered group} construct.  Normal groups get
+their number implicitly, based on their position, which can be
+inconvenient.  This construct allows you to force a particular group
+number.  There is no particular restriction on the numbering,
+e.g.@: you can have several groups with the same number.
+Implicitly numbered groups always get the smallest integer larger than
+the one of any previous group.
+
 @item \@var{digit}
 matches the same text that matched the @var{digit}th occurrence of a
 grouping (@samp{\( @dots{} \)}) construct.