REXX builtin function - WORDPOS

Returns the word position in a given string
WORDPOS(srch-str, str-srched,)
where
srch-str -> String to be searched
Str-srched -> String in which srch-str is searched for
Start pos -> start of search. This is optional and by default it is 0 i.e beginning of str-srched
Example:
WORDPOS('dog', 'barking dogs seldom bite')
--returns 2
WORDPOS('tide', 'time waits for none')
--returns 0
WORDPOS('be', 'To be or not to be',3)
--returns 6 since the search starts at 3rd word 'or'