HELP ISSUBSTRING                  Updated, Mark Rubinstein  January 1986

    issubstring(string1, index, string2) -> integer or false
    issubstring(string1, string2) -> integer or false

ISSUBSTRING takes a string (or word) STRING1, an integer INDEX and a
second string (or word) STRING2 and returns either FALSE or an integer.

The integer is optional and defaults to 1.

It looks for an occurrence of STRING1 starting at location INDEX in
STRING2, or at some subsequent location, and if it finds one returns the
starting location of the matching substring.  If it finds no such
location, the result is FALSE, e.g.

    issubstring('the', 1, 'all the cats')=>
    ** 5
    issubstring('the',6, 'all the cats') =>
    ** <false>
    issubstring("hat", 1, "thatch") =>
    ** 2

SEE ALSO
 HELP * SUBSTRING, *ISSUBSTRING_LIM, *LOCCHAR, *STRMEMBER, *ISENDSTRING
 HELP * STRINGS.
 REF * STRINGS

--- C.all/help/issubstring ---------------------------------------------
--- Copyright University of Sussex 1988. All rights reserved. ----------
