5.19  Unit: format

[procedure] (format DESTINATION FORMAT-STRING . ARGUMENTS)
An almost complete implementation of Common LISP format description according to the CL reference book Common LISP from Guy L. Steele, Digital Press. This code was originally part of SLIB. The author is Dirk Lutzebaeck.

Returns #t, #f or a string; has side effect of printing according to FORMAT-STRING. If DESTINATION is #t, the output is to the current output port and #t is returned. If DESTINATION is #f, a formatted string is returned as the result of the call. If DESTINATION is a string, DESTINATION is regarded as the format string; FORMAT-STRING is then the first argument and the output is returned as a string. If DESTINATION is a number, the output is to the value of (current-error-port). Otherwise DESTINATION must be an output port and #t is returned.

FORMAT-STRING must be a string. In case of a formatting error format returns #f and prints a message on the value of (current-error-port). Characters are output as if the string were output by the display function with the exception of those prefixed by a tilde (~). For a detailed description of the FORMAT-STRING syntax please consult a Common LISP format reference manual. A list of all supported, non-supported and extended directives can be found in format.txt.

This unit uses definitions from the extras unit.

format implements SRFI-28 24


24 http//srfi.schemers.org/srfi-28/srfi-28.html