An almost complete implementation of Common LISP format description according to the CL reference book Common LISP from Guy L. Steele, Digital Press. Backward compatible to most of the available Scheme format implementations.
#f or a string; has side effect of printing
according to format-string. If destination is
the output is to the current output port and
#t is returned. If
#f, a formatted string is returned as the
result of the call. NEW: 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 current error port
if available by the implementation. Otherwise destination must be
an output port and
#t is returned.
format-string must be a string. In case of a formatting error
#f and prints a message on the current output or
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. For a test suite
to verify this format implementation load formatst.scm.