write object [&key*] ⇒ object

write-byte integer binary-output-stream

write-char character [output-stream] ⇒ character

write-string string [output-stream] &key :start :end ⇒ string

write-line string [output-stream] &key :start :end ⇒ string


terpri [output-stream] ⇒ nil

fresh-line [output-stream] ⇒ boolean

finish-output [output-stream] ⇒ nil

force-output [output-stream] ⇒ nil

clear-output [output-stream] ⇒ nil


write-to-string object [&key*] ⇒ object

prin1-to-string object ⇒ object

princ-to-string object ⇒ object

prin1 object [output-stream] ⇒ object

produces output suitable for input to read.

like prin1 except that the printed representation of object is preceded by a newline and followed by a space.

pprint object [output-stream] ⇒ object

just like print except that the trailing space is omitted and object is printed with the print-pretty flag non-nil to produce pretty output.

princ object [output-stream] ⇒ object

is just like prin1 except that the output has no escape characters. The general rule is that output from princ is intended to look good to people, while output from prin1 is intended to be acceptable to read.


format destination control-string args* ⇒ result

Creates formatted output using the control-string and observing tilde indicated directives. If destination is a string, a stream, or t, then the result is nil. Otherwise, the result is a string containing the formatted output.

(format nil "Hello, ~a" 'lisp) ;⇒ "Hello, LISP!"

Basic Directives:

  • ~A —Aesthetic. Print without escape characters (princ).
  • ~S —Standard. Print with escape characters (prin1).
  • ~% —Newline character. ~n% outputs n newlines.

Number Directives:

  • ~D —Decimal.
  • ~B —Binary. Prints radix 2.
  • ~O —Octal. Prints radix 8.
  • ~X —Hexadecimal. Prints radix 16.
  • ~R —Radix. ~nR prints in radix n.
  • ~F —Float. ~width,count,scale,overflowchar,padcharF
  • ~E —Exponential notation. ~width,count,scale,overflowchar,padchar,exptcharE.
  • ~G —General floating-point. ~width,count,scale,overflowchar,padchar,exptcharG.
  • ~$ —Dollars. ~count,min-count,min-width,padchar$

The @ modifer causes the sign to always print. : adds commas between groups of digits. The most general form of ~D is ~mincol,padchar,commachar,comma-intervalD.

Formatting Directives:

  • ~W —Write. Obey every printer-control variable (write).
  • ~C —Character.
  • ~~ —Escape tilde character.
  • ~& —Fresh line.
  • ~<newline> —Ignores the newline and any whitespace that follows.
  • ~_ —Conditional newline.
  • ~| —Page separator character.
  • ~T —Tabulate.
  • ~I —Indent.

Control Directives:

  • ~:> —Logical Block.
  • ~/ —Call function.
  • ~< —Justification.
  • ~> —End justifcation.
  • ~* —Go-To.
  • ~[ —Conditional expression.
  • ~] —End conditional expression.
  • ~{ —Iteration.
  • ~} —End iteration.
  • ~? —Recursive processing.
  • ~( —Case conversion.
  • ~) —End case conversion.
  • ~P —Plural.
  • ~; —Clause separator.
  • ~^ —Escape upward.