stran(s)                     translate characters
stran(s,t)                   translate characters
stran(s,t,f)                 translate characters

    Return string  formed by  translating characters  in string  s matching
    characters in string  f to corresponding  character in string  t. If no
    corresponding character in string t then replace with blank.  If string
    f not passed  then string value  of TRANS_FROM built-in  variable used.
    If string t not passed then string value of TRANS_TO built-in  variable
    used.  Default value of:

    TRANS_TO   ==> "abcdefghijklmnopqrstuvwxyz"
    TRANS_FROM ==> "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

    Using default values of TRANS_TO/TRANS_FROM will convert all upper case
    to lower case.

    Example: convert "<> {} []" pairs ==> "()" pairs

    stran(str,"()()()","<>{}[]");