index buggy for matching patterns longer than 3

[Jean-Francois Cardoso]

There is an error in the logic of find.m which makes it report a
matching pattern when *only* the first three characters match.
For example,
     index("abc---", "abc+++")
returns 1 rather than 0.

The following patch fixes this and also adds the relevant new
testcases.

Cheers, JF


================================================================
*** octave-2.9.13/scripts/strings/index.m       Wed Jun 20 20:10:04 2007
--- index.m     Mon Aug  6 23:35:01 2007
***************
*** 106,111 ****
--- 106,112 ----
          break;
        endif
        endfor
+       v = [] ;
      endif

    endif
***************
*** 122,130 ****
--- 123,134 ----
  %!assert(index("astringbstringcstring", "st"), 2)
  %!assert(index("astringbstringcstring", "str"), 2)
  %!assert(index("astringbstringcstring", "string"), 2)
+ %!assert(index("abc---", "abc+++"), 0)

  ## test everything out in reverse
  %!assert(index("astringbstringcstring", "s", "last"), 16)
  %!assert(index("astringbstringcstring", "st", "last"), 16)
  %!assert(index("astringbstringcstring", "str", "last"), 16)
  %!assert(index("astringbstringcstring", "string", "last"), 16)
+ %!assert(index("abc---", "abc+++", "last"), 0)
+

================================================================

Changelog entry:


2007-08-04  Jean-Francois Cardoso  <address@hidden>

        * strings/index.m: correct for strings differing after the third
        position (bug reported by Maude Martin).