INSTR( [start-position,] string-searched$, string- pattern$ [,size] )
Returns the position at which string-pattern$ occurs in string-searched$,
beginning at start-position. If start-position is not provided it will default to 1.
Both the position returned and start-position use 1 for the first character, 2 for
the second, etc.
The function returns zero if string-pattern$ is not found.
If the optional parameter “size” is specified the “string-pattern” is treated as a regular expression. See Appendix E for the details.