(Regexp Backslash, Regexp Replace): Add index entries for ``back reference''

and mention the term itself in the text.

1 files changed, 7 insertions, 5 deletions

diff --git a/man/search.texi b/man/search.texi
index a38f56e3f26..ab109445091 100644
--- a/man/search.texi
+++ b/man/search.texi
@@ -750,8 +750,9 @@ can add groups for syntactic purposes without interfering with
 the numbering of the groups that are meant to be referred to.
 
 @item \@var{d}
+@cindex back reference, in regexp
 matches the same text that matched the @var{d}th occurrence of a
-@samp{\( @dots{} \)} construct.
+@samp{\( @dots{} \)} construct (a.k.a.@: @dfn{back reference}).
 
 After the end of a @samp{\( @dots{} \)} construct, the matcher remembers
 the beginning and end of the text matched by that construct.  Then,
@@ -1002,15 +1003,16 @@ any match for a specified pattern.
 Replace every match for @var{regexp} with @var{newstring}.
 @end table
 
+@cindex back reference, in regexp replacement
   In @code{replace-regexp}, the @var{newstring} need not be constant:
 it can refer to all or part of what is matched by the @var{regexp}.
 @samp{\&} in @var{newstring} stands for the entire match being
 replaced.  @samp{\@var{d}} in @var{newstring}, where @var{d} is a
 digit, stands for whatever matched the @var{d}th parenthesized
-grouping in @var{regexp}.  @samp{\#} refers to the count of
-replacements already made in this command, as a decimal number.  In
-the first replacement, @samp{\#} stands for @samp{0}; in the second,
-for @samp{1}; and so on.  For example,
+grouping in @var{regexp} (a.k.a.@: ``back reference'').  @samp{\#}
+refers to the count of replacements already made in this command, as a
+decimal number.  In the first replacement, @samp{\#} stands for
+@samp{0}; in the second, for @samp{1}; and so on.  For example,
 
 @example
 M-x replace-regexp @key{RET} c[ad]+r @key{RET} \&-safe @key{RET}