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diff --git a/format.texi b/format.texi new file mode 100644 index 0000000..34d5e0a --- /dev/null +++ b/format.texi @@ -0,0 +1,451 @@ + +@menu +* Format Interface:: +* Format Specification:: +@end menu + +@node Format Interface, Format Specification, Format, Format +@subsection Format Interface + +@defun format destination format-string . arguments +An almost complete implementation of Common LISP format description +according to the CL reference book @cite{Common LISP} from Guy L. +Steele, Digital Press. Backward compatible to most of the available +Scheme format implementations. + +Returns @code{#t}, @code{#f} or a string; has side effect of printing +according to @var{format-string}. If @var{destination} is @code{#t}, +the output is to the current output port and @code{#t} is returned. If +@var{destination} is @code{#f}, a formatted string is returned as the +result of the call. NEW: If @var{destination} is a string, +@var{destination} is regarded as the format string; @var{format-string} is +then the first argument and the output is returned as a string. If +@var{destination} is a number, the output is to the current error port +if available by the implementation. Otherwise @var{destination} must be +an output port and @code{#t} is returned.@refill + +@var{format-string} must be a string. In case of a formatting error +format returns @code{#f} and prints a message on the current output or +error port. Characters are output as if the string were output by the +@code{display} function with the exception of those prefixed by a tilde +(~). For a detailed description of the @var{format-string} syntax +please consult a Common LISP format reference manual. For a test suite +to verify this format implementation load @file{formatst.scm}. Please +send bug reports to @code{lutzeb@@cs.tu-berlin.de}. + +Note: @code{format} is not reentrant, i.e. only one @code{format}-call +may be executed at a time. + +@end defun + +@node Format Specification, , Format Interface, Format +@subsection Format Specification (Format version 3.1) + +Please consult a Common LISP format reference manual for a detailed +description of the format string syntax. For a demonstration of the +implemented directives see @file{formatst.scm}.@refill + +This implementation supports directive parameters and modifiers +(@code{:} and @code{@@} characters). Multiple parameters must be +separated by a comma (@code{,}). Parameters can be numerical parameters +(positive or negative), character parameters (prefixed by a quote +character (@code{'}), variable parameters (@code{v}), number of rest +arguments parameter (@code{#}), empty and default parameters. Directive +characters are case independent. The general form of a directive +is:@refill + +@noindent +@var{directive} ::= ~@{@var{directive-parameter},@}[:][@@]@var{directive-character} + +@noindent +@var{directive-parameter} ::= [ [-|+]@{0-9@}+ | '@var{character} | v | # ] + + +@subsubsection Implemented CL Format Control Directives + +Documentation syntax: Uppercase characters represent the corresponding +control directive characters. Lowercase characters represent control +directive parameter descriptions. + +@table @asis +@item @code{~A} +Any (print as @code{display} does). +@table @asis +@item @code{~@@A} +left pad. +@item @code{~@var{mincol},@var{colinc},@var{minpad},@var{padchar}A} +full padding. +@end table +@item @code{~S} +S-expression (print as @code{write} does). +@table @asis +@item @code{~@@S} +left pad. +@item @code{~@var{mincol},@var{colinc},@var{minpad},@var{padchar}S} +full padding. +@end table +@item @code{~D} +Decimal. +@table @asis +@item @code{~@@D} +print number sign always. +@item @code{~:D} +print comma separated. +@item @code{~@var{mincol},@var{padchar},@var{commachar}D} +padding. +@end table +@item @code{~X} +Hexadecimal. +@table @asis +@item @code{~@@X} +print number sign always. +@item @code{~:X} +print comma separated. +@item @code{~@var{mincol},@var{padchar},@var{commachar}X} +padding. +@end table +@item @code{~O} +Octal. +@table @asis +@item @code{~@@O} +print number sign always. +@item @code{~:O} +print comma separated. +@item @code{~@var{mincol},@var{padchar},@var{commachar}O} +padding. +@end table +@item @code{~B} +Binary. +@table @asis +@item @code{~@@B} +print number sign always. +@item @code{~:B} +print comma separated. +@item @code{~@var{mincol},@var{padchar},@var{commachar}B} +padding. +@end table +@item @code{~@var{n}R} +Radix @var{n}. +@table @asis +@item @code{~@var{n},@var{mincol},@var{padchar},@var{commachar}R} +padding. +@end table +@item @code{~@@R} +print a number as a Roman numeral. +@item @code{~:@@R} +print a number as an ``old fashioned'' Roman numeral. +@item @code{~:R} +print a number as an ordinal English number. +@item @code{~R} +print a number as a cardinal English number. +@item @code{~P} +Plural. +@table @asis +@item @code{~@@P} +prints @code{y} and @code{ies}. +@item @code{~:P} +as @code{~P but jumps 1 argument backward.} +@item @code{~:@@P} +as @code{~@@P but jumps 1 argument backward.} +@end table +@item @code{~C} +Character. +@table @asis +@item @code{~@@C} +prints a character as the reader can understand it (i.e. @code{#\} prefixing). +@item @code{~:C} +prints a character as emacs does (eg. @code{^C} for ASCII 03). +@end table +@item @code{~F} +Fixed-format floating-point (prints a flonum like @var{mmm.nnn}). +@table @asis +@item @code{~@var{width},@var{digits},@var{scale},@var{overflowchar},@var{padchar}F} +@item @code{~@@F} +If the number is positive a plus sign is printed. +@end table +@item @code{~E} +Exponential floating-point (prints a flonum like @var{mmm.nnn}@code{E}@var{ee}). +@table @asis +@item @code{~@var{width},@var{digits},@var{exponentdigits},@var{scale},@var{overflowchar},@var{padchar},@var{exponentchar}E} +@item @code{~@@E} +If the number is positive a plus sign is printed. +@end table +@item @code{~G} +General floating-point (prints a flonum either fixed or exponential). +@table @asis +@item @code{~@var{width},@var{digits},@var{exponentdigits},@var{scale},@var{overflowchar},@var{padchar},@var{exponentchar}G} +@item @code{~@@G} +If the number is positive a plus sign is printed. +@end table +@item @code{~$} +Dollars floating-point (prints a flonum in fixed with signs separated). +@table @asis +@item @code{~@var{digits},@var{scale},@var{width},@var{padchar}$} +@item @code{~@@$} +If the number is positive a plus sign is printed. +@item @code{~:@@$} +A sign is always printed and appears before the padding. +@item @code{~:$} +The sign appears before the padding. +@end table +@item @code{~%} +Newline. +@table @asis +@item @code{~@var{n}%} +print @var{n} newlines. +@end table +@item @code{~&} +print newline if not at the beginning of the output line. +@table @asis +@item @code{~@var{n}&} +prints @code{~&} and then @var{n-1} newlines. +@end table +@item @code{~|} +Page Separator. +@table @asis +@item @code{~@var{n}|} +print @var{n} page separators. +@end table +@item @code{~~} +Tilde. +@table @asis +@item @code{~@var{n}~} +print @var{n} tildes. +@end table +@item @code{~}<newline> +Continuation Line. +@table @asis +@item @code{~:}<newline> +newline is ignored, white space left. +@item @code{~@@}<newline> +newline is left, white space ignored. +@end table +@item @code{~T} +Tabulation. +@table @asis +@item @code{~@@T} +relative tabulation. +@item @code{~@var{colnum,colinc}T} +full tabulation. +@end table +@item @code{~?} +Indirection (expects indirect arguments as a list). +@table @asis +@item @code{~@@?} +extracts indirect arguments from format arguments. +@end table +@item @code{~(@var{str}~)} +Case conversion (converts by @code{string-downcase}). +@table @asis +@item @code{~:(@var{str}~)} +converts by @code{string-capitalize}. +@item @code{~@@(@var{str}~)} +converts by @code{string-capitalize-first}. +@item @code{~:@@(@var{str}~)} +converts by @code{string-upcase}. +@end table +@item @code{~*} +Argument Jumping (jumps 1 argument forward). +@table @asis +@item @code{~@var{n}*} +jumps @var{n} arguments forward. +@item @code{~:*} +jumps 1 argument backward. +@item @code{~@var{n}:*} +jumps @var{n} arguments backward. +@item @code{~@@*} +jumps to the 0th argument. +@item @code{~@var{n}@@*} +jumps to the @var{n}th argument (beginning from 0) +@end table +@item @code{~[@var{str0}~;@var{str1}~;...~;@var{strn}~]} +Conditional Expression (numerical clause conditional). +@table @asis +@item @code{~@var{n}[} +take argument from @var{n}. +@item @code{~@@[} +true test conditional. +@item @code{~:[} +if-else-then conditional. +@item @code{~;} +clause separator. +@item @code{~:;} +default clause follows. +@end table +@item @code{~@{@var{str}~@}} +Iteration (args come from the next argument (a list)). Iteration +bounding is controlled by configuration variables +@var{format:iteration-bounded} and @var{format:max-iterations}. +With both variables default, a maximum of 100 iterations will be +performed. +@table @asis +@item @code{~@var{n}@{} +at most @var{n} iterations. +@item @code{~:@{} +args from next arg (a list of lists). +@item @code{~@@@{} +args from the rest of arguments. +@item @code{~:@@@{} +args from the rest args (lists). +@end table +@item @code{~^} +Up and out. +@table @asis +@item @code{~@var{n}^} +aborts if @var{n} = 0 +@item @code{~@var{n},@var{m}^} +aborts if @var{n} = @var{m} +@item @code{~@var{n},@var{m},@var{k}^} +aborts if @var{n} <= @var{m} <= @var{k} +@end table +@end table + + +@subsubsection Not Implemented CL Format Control Directives + +@table @asis +@item @code{~:A} +print @code{#f} as an empty list (see below). +@item @code{~:S} +print @code{#f} as an empty list (see below). +@item @code{~<~>} +Justification. +@item @code{~:^} +(sorry I don't understand its semantics completely) +@end table + + +@subsubsection Extended, Replaced and Additional Control Directives + +@table @asis +@item @code{~@var{mincol},@var{padchar},@var{commachar},@var{commawidth}D} +@item @code{~@var{mincol},@var{padchar},@var{commachar},@var{commawidth}X} +@item @code{~@var{mincol},@var{padchar},@var{commachar},@var{commawidth}O} +@item @code{~@var{mincol},@var{padchar},@var{commachar},@var{commawidth}B} +@item @code{~@var{n},@var{mincol},@var{padchar},@var{commachar},@var{commawidth}R} +@var{commawidth} is the number of characters between two comma characters. +@end table + +@table @asis +@item @code{~I} +print a R4RS complex number as @code{~F~@@Fi} with passed parameters for +@code{~F}. +@item @code{~Y} +Pretty print formatting of an argument for scheme code lists. +@item @code{~K} +Same as @code{~?.} +@item @code{~!} +Flushes the output if format @var{destination} is a port. +@item @code{~_} +Print a @code{#\space} character +@table @asis +@item @code{~@var{n}_} +print @var{n} @code{#\space} characters. +@end table +@item @code{~/} +Print a @code{#\tab} character +@table @asis +@item @code{~@var{n}/} +print @var{n} @code{#\tab} characters. +@end table +@item @code{~@var{n}C} +Takes @var{n} as an integer representation for a character. No arguments +are consumed. @var{n} is converted to a character by +@code{integer->char}. @var{n} must be a positive decimal number.@refill +@item @code{~:S} +Print out readproof. Prints out internal objects represented as +@code{#<...>} as strings @code{"#<...>"} so that the format output can always +be processed by @code{read}. +@refill +@item @code{~:A} +Print out readproof. Prints out internal objects represented as +@code{#<...>} as strings @code{"#<...>"} so that the format output can always +be processed by @code{read}. +@item @code{~Q} +Prints information and a copyright notice on the format implementation. +@table @asis +@item @code{~:Q} +prints format version. +@end table +@refill +@item @code{~F, ~E, ~G, ~$} +may also print number strings, i.e. passing a number as a string and +format it accordingly. +@end table + +@subsubsection Configuration Variables + +Format has some configuration variables at the beginning of +@file{format.scm} to suit the systems and users needs. There should be +no modification necessary for the configuration that comes with SLIB. +If modification is desired the variable should be set after the format +code is loaded. Format detects automatically if the running scheme +system implements floating point numbers and complex numbers. + +@table @asis + +@item @var{format:symbol-case-conv} +Symbols are converted by @code{symbol->string} so the case type of the +printed symbols is implementation dependent. +@code{format:symbol-case-conv} is a one arg closure which is either +@code{#f} (no conversion), @code{string-upcase}, @code{string-downcase} +or @code{string-capitalize}. (default @code{#f}) + +@item @var{format:iobj-case-conv} +As @var{format:symbol-case-conv} but applies for the representation of +implementation internal objects. (default @code{#f}) + +@item @var{format:expch} +The character prefixing the exponent value in @code{~E} printing. (default +@code{#\E}) + +@item @var{format:iteration-bounded} +When @code{#t}, a @code{~@{...~@}} control will iterate no more than the +number of times specified by @var{format:max-iterations} regardless of +the number of iterations implied by modifiers and arguments. +When @code{#f}, a @code{~@{...~@}} control will iterate the number of +times implied by modifiers and arguments, unless termination is forced +by language or system limitations. (default @code{#t}) + +@item @var{format:max-iterations} +The maximum number of iterations performed by a @code{~@{...~@}} control. +Has effect only when @var{format:iteration-bounded} is @code{#t}. +(default 100) + +@end table + +@subsubsection Compatibility With Other Format Implementations + +@table @asis +@item SLIB format 2.x: +See @file{format.doc}. + +@item SLIB format 1.4: +Downward compatible except for padding support and @code{~A}, @code{~S}, +@code{~P}, @code{~X} uppercase printing. SLIB format 1.4 uses C-style +@code{printf} padding support which is completely replaced by the CL +@code{format} padding style. + +@item MIT C-Scheme 7.1: +Downward compatible except for @code{~}, which is not documented +(ignores all characters inside the format string up to a newline +character). (7.1 implements @code{~a}, @code{~s}, +~@var{newline}, @code{~~}, @code{~%}, numerical and variable +parameters and @code{:/@@} modifiers in the CL sense).@refill + +@item Elk 1.5/2.0: +Downward compatible except for @code{~A} and @code{~S} which print in +uppercase. (Elk implements @code{~a}, @code{~s}, @code{~~}, and +@code{~%} (no directive parameters or modifiers)).@refill + +@item Scheme->C 01nov91: +Downward compatible except for an optional destination parameter: S2C +accepts a format call without a destination which returns a formatted +string. This is equivalent to a #f destination in S2C. (S2C implements +@code{~a}, @code{~s}, @code{~c}, @code{~%}, and @code{~~} (no directive +parameters or modifiers)).@refill + +@end table + +This implementation of format is solely useful in the SLIB context +because it requires other components provided by SLIB.@refill |