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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.
Returns #t
, #f
or a string; has side effect of printing
according to fmt. If destination is #t
,
the output is to the current output port and #!void
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; fmt 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 #!void
is returned.
fmt must be a string or an instance of gnu.text.MessageFormat
or java.text.MessageFormat
. If fmt is a string,
it is parsed as if by parse-format
.
Parses format-string
, which is a string of the form of a Common LISP
format description. Returns an instance of gnu.text.ReportFormat
,
which can be passed to the format
function.
A format string passed to format
or parse-format
consists of format directives (that start with ‘~’),
and regular characters (that are written directly to the destination).
Most of the Common Lisp (and Slib) format directives are implemented.
Neither justification, nor pretty-printing are supported yet.
Plus of course, we need documentation for format
!
Documentation syntax: Uppercase characters represent the corresponding control directive characters. Lowercase characters represent control directive parameter descriptions.
~A
Any (print as display
does).
~@A
left pad.
~mincol,colinc,minpad,padcharA
full padding.
~S
S-expression (print as write
does).
~@S
left pad.
~mincol,colinc,minpad,padcharS
full padding.
~C
Character.
~@C
prints a character as the reader can understand it (i.e. #\
prefixing).
~:C
prints a character as emacs does (eg. ^C
for ASCII 03).
~D
Decimal.
~@D
print number sign always.
~:D
print comma separated.
~mincol,padchar,commachar,commawidthD
padding.
~X
Hexadecimal.
~@X
print number sign always.
~:X
print comma separated.
~mincol,padchar,commachar,commawidthX
padding.
~O
Octal.
~@O
print number sign always.
~:O
print comma separated.
~mincol,padchar,commachar,commawidthO
padding.
~B
Binary.
~@B
print number sign always.
~:B
print comma separated.
~mincol,padchar,commachar,commawidthB
padding.
~nR
Radix n.
~n,mincol,padchar,commachar,commawidthR
padding.
~@R
print a number as a Roman numeral.
~:@R
print a number as an “old fashioned” Roman numeral.
~:R
print a number as an ordinal English number.
~R
~P
Plural.
~@P
prints y
and ies
.
~:P
as ~P but jumps 1 argument backward.
~:@P
as ~@P but jumps 1 argument backward.
commawidth is the number of characters between two comma characters.
~F
Fixed-format floating-point (prints a flonum like mmm.nnn).
~width,digits,scale,overflowchar,padcharF
~@F
If the number is positive a plus sign is printed.
~E
Exponential floating-point (prints a flonum like mmm.nnnE
ee)
~width,digits,exponentdigits,scale,overflowchar,padchar,exponentcharE
~@E
If the number is positive a plus sign is printed.
~G
General floating-point (prints a flonum either fixed or exponential).
~width,digits,exponentdigits,scale,overflowchar,padchar,exponentcharG
~@G
If the number is positive a plus sign is printed.
A slight difference from Common Lisp: If the number is printed in fixed form and the fraction is zero, then a zero digit is printed for the fraction, if allowed by the width and digits is unspecified.
~$
Dollars floating-point (prints a flonum in fixed with signs separated).
~digits,scale,width,padchar$
~@$
If the number is positive a plus sign is printed.
~:@$
A sign is always printed and appears before the padding.
~:$
The sign appears before the padding.
~%
Newline.
~n%
print n newlines.
~&
print newline if not at the beginning of the output line.
~n&
prints ~&
and then n-1 newlines.
~|
Page Separator.
~n|
print n page separators.
~~
Tilde.
~n~
print n tildes.
~
<newline>Continuation Line.
~:
<newline>newline is ignored, white space left.
~@
<newline>newline is left, white space ignored.
~T
Tabulation.
~@T
relative tabulation.
~colnum,colincT
full tabulation.
~?
Indirection (expects indirect arguments as a list).
~@?
extracts indirect arguments from format arguments.
~(str~)
Case conversion (converts by string-downcase
).
~:(str~)
converts by string-capitalize
.
~@(str~)
converts by string-capitalize-first
.
~:@(str~)
converts by string-upcase
.
~*
Argument Jumping (jumps 1 argument forward).
~n*
jumps n arguments forward.
~:*
jumps 1 argument backward.
~n:*
jumps n arguments backward.
~@*
jumps to the 0th argument.
~n@*
jumps to the nth argument (beginning from 0)
~[str0~;str1~;...~;strn~]
Conditional Expression (numerical clause conditional).
~{str~}
Iteration (args come from the next argument (a list)).
~^
Up and out.
~n^
aborts if n = 0
~n,m^
aborts if n = m
~n,m,k^
aborts if n <= m <= k
~:A
print #f
as an empty list (see below).
~:S
print #f
as an empty list (see below).
~<~>
Justification.
~:^
These are not necesasrily implemented in Kawa!
~I
print a R4RS complex number as ~F~@Fi
with passed parameters for
~F
.
~Y
Pretty print formatting of an argument for scheme code lists.
~K
Same as ~?.
~!
Flushes the output if format destination is a port.
~_
Print a #\space
character
~n_
print n #\space
characters.
~nC
Takes n as an integer representation for a character. No arguments
are consumed. n is converted to a character by
integer->char
. n must be a positive decimal number.
~:S
Print out readproof. Prints out internal objects represented as
#<...>
as strings "#<...>"
so that the format output can always
be processed by read
.
~:A
Print out readproof. Prints out internal objects represented as
#<...>
as strings "#<...>"
so that the format output can always
be processed by read
.
~F, ~E, ~G, ~$
may also print number strings, i.e. passing a number as a string and format it accordingly.
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