Improve string functions.

* mfd/bi_string.m4 (index, rindex): Take an optional third
argument, indicating where to start searching.
* NEWS, doc/mailfromd.texi: Document changes to index and rindex.


git-svn-id: file:///svnroot/mailfromd/trunk@1707 7a8a7f39-df28-0410-adc6-e0d955640f24

1 files changed, 18 insertions, 1 deletions

diff --git a/doc/mailfromd.texi b/doc/mailfromd.texi
index 53039974..058e53ef 100644
--- a/doc/mailfromd.texi
+++ b/doc/mailfromd.texi
@@ -5634,7 +5634,8 @@ domainpart "gray@@gnu.org.ua" @result{} "gnu.org.ua"
 
 @anchor{index-built-in}
 @deftypefn {Built-in Function} number index (string @var{s}, string @var{t})
-
+@deftypefnx {Built-in Function} number index (string @var{s}, string @var{t}, @
+                                              number @var{start})
   Returns the index of the first occurrence of the string @var{t} in
 the string @var{s}, or -1 if @var{t} is not present.
 
@@ -5642,6 +5643,13 @@ the string @var{s}, or -1 if @var{t} is not present.
 index("string of rings", "ring") @result{} 2
 @end smallexample
 
+  Optional argument @var{start}, if supplied, indicates the position
+in string where to start searching. 
+
+@smallexample
+index("string of rings", "ring", 3) @result{} 10
+@end smallexample
+
   To find the last occurrence of a substring, use the function
 @var{rindex} (@pxref{rindex}).
 @end deftypefn
@@ -5684,6 +5692,8 @@ revstr("foobar") @result{} "raboof"
   
 @anchor{rindex}
 @deftypefn {Built-in Function} number rindex (string @var{s}, string @var{t})
+@deftypefnx {Built-in Function} number rindex (string @var{s}, string @var{t}, @
+                                               number @var{start})
 
   Returns the index of the last occurrence of the string @var{t} in
 the string @var{s}, or -1 if @var{t} is not present.
@@ -5692,6 +5702,13 @@ the string @var{s}, or -1 if @var{t} is not present.
 rindex("string of rings", "ring") @result{} 10
 @end smallexample
 
+  Optional argument @var{start}, if supplied, indicates the position
+in string where to start searching. E.g.:
+
+@smallexample
+rindex("string of rings", "ring", 10) @result{} 2
+@end smallexample
+
   See also @ref{index-built-in, @code{index} built-in function,  String manipulation}.
 @end deftypefn