returns the length of a string
str_len("Hello World",Len)
str_len(String,Len) (i,o)
string(string) (x) string to be evaluated
integer(Int) (x) length of string.
Determines the length of String. Succeeds if the length could be matched with Len.
No runtime errors.
readln(String), ( str_len(String,Len), Len < 15, write(String),nl ; write("was too long."),nl ).
prolog-process, client-server, object