%LOCATE is modeled after VAX MACRO's %LOCATE macro string
    operator and the OpenVMS DCL lexical function F$LOCATE. %LOCATE
    is used to locate one string within another. The value returned
    is the decimal offset to the first occurrence of the first string
    within the second string. The offset to the first character is 0.
    If the first string cannot be found within the second string, the
    length of the second string is returned.