make-custom-textual-output-port
call-with-string-output-port
flush-output-port put-string
- get-char get-datum get-line get-string-all lookahead-char
+ get-char get-datum get-line get-string-all get-string-n get-string-n!
+ lookahead-char
put-char put-datum put-string
standard-input-port standard-output-port standard-error-port