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Diffstat (limited to 'format.scm')
| -rw-r--r-- | format.scm | 1688 |
1 files changed, 1688 insertions, 0 deletions
diff --git a/format.scm b/format.scm new file mode 100644 index 0000000..c9e1d12 --- /dev/null +++ b/format.scm @@ -0,0 +1,1688 @@ +;;; "format.scm" Common LISP text output formatter for SLIB +; Written 1992-1994 by Dirk Lutzebaeck (lutzeb@cs.tu-berlin.de) +; +; This code is in the public domain. + +; Authors of the original version (< 1.4) were Ken Dickey and Aubrey Jaffer. +; Please send error reports to the email address above. +; For documentation see slib.texi and format.doc. +; For testing load formatst.scm. +; +; Version 3.0 + +(provide 'format) +(require 'string-case) +(require 'string-port) +(require 'multiarg/and-) +(require 'rev4-optional-procedures) + +;;; Configuration ------------------------------------------------------------ + +(define format:symbol-case-conv #f) +;; Symbols are converted by symbol->string so the case of the printed +;; symbols is implementation dependent. format:symbol-case-conv is a +;; one arg closure which is either #f (no conversion), string-upcase!, +;; string-downcase! or string-capitalize!. + +(define format:iobj-case-conv #f) +;; As format:symbol-case-conv but applies for the representation of +;; implementation internal objects. + +(define format:expch #\E) +;; The character prefixing the exponent value in ~e printing. + +(define format:iteration-bounded #t) +;; If #t, "~{...~}" iterates no more than format:max-iterations times; +;; if #f, there is no bound. + +(define format:max-iterations 100) +;; Compatible with previous versions. + +(define format:floats (provided? 'inexact)) +;; Detects if the scheme system implements flonums (see at eof). + +(define format:complex-numbers (provided? 'complex)) +;; Detects if the scheme system implements complex numbers. + +(define format:radix-pref (char=? #\# (string-ref (number->string 8 8) 0))) +;; Detects if number->string adds a radix prefix. + +(define format:ascii-non-printable-charnames + '#("nul" "soh" "stx" "etx" "eot" "enq" "ack" "bel" + "bs" "ht" "nl" "vt" "np" "cr" "so" "si" + "dle" "dc1" "dc2" "dc3" "dc4" "nak" "syn" "etb" + "can" "em" "sub" "esc" "fs" "gs" "rs" "us" "space")) + +;;; End of configuration ---------------------------------------------------- + +(define format:version "3.0") +(define format:port #f) ; curr. format output port +(define format:output-col 0) ; curr. format output tty column +(define format:flush-output #f) ; flush output at end of formatting +(define format:case-conversion #f) +(define format:error-continuation #f) +(define format:args #f) +(define format:pos 0) ; curr. format string parsing position +(define format:arg-pos 0) ; curr. format argument position + ; this is global for error presentation + +; format string and char output routines on format:port + +(define (format:out-str str) + (if format:case-conversion + (display (format:case-conversion str) format:port) + (display str format:port)) + (set! format:output-col + (+ format:output-col (string-length str)))) + +(define (format:out-char ch) + (if format:case-conversion + (display (format:case-conversion (string ch)) format:port) + (write-char ch format:port)) + (set! format:output-col + (if (char=? ch #\newline) + 0 + (+ format:output-col 1)))) + +;(define (format:out-substr str i n) ; this allocates a new string +; (display (substring str i n) format:port) +; (set! format:output-col (+ format:output-col n))) + +(define (format:out-substr str i n) + (do ((k i (+ k 1))) + ((= k n)) + (write-char (string-ref str k) format:port)) + (set! format:output-col (+ format:output-col n))) + +;(define (format:out-fill n ch) ; this allocates a new string +; (format:out-str (make-string n ch))) + +(define (format:out-fill n ch) + (do ((i 0 (+ i 1))) + ((= i n)) + (write-char ch format:port)) + (set! format:output-col (+ format:output-col n))) + +; format's user error handler + +(define (format:error . args) ; never returns! + (let ((error-continuation format:error-continuation) + (format-args format:args) + (port (current-error-port))) + (set! format:error format:intern-error) + (if (and (>= (length format:args) 2) + (string? (cadr format:args))) + (let ((format-string (cadr format-args))) + (if (not (zero? format:arg-pos)) + (set! format:arg-pos (- format:arg-pos 1))) + (format port "~%FORMAT: error with call: (format ~a \"~a<===~a\" ~ + ~{~a ~}===>~{~a ~})~% " + (car format:args) + (substring format-string 0 format:pos) + (substring format-string format:pos + (string-length format-string)) + (format:list-head (cddr format:args) format:arg-pos) + (list-tail (cddr format:args) format:arg-pos))) + (format port + "~%FORMAT: error with call: (format~{ ~a~})~% " + format:args)) + (apply format port args) + (newline port) + (set! format:error format:error-save) + (set! format:error-continuation error-continuation) + (format:abort) + (format:intern-error "format:abort does not jump to toplevel!"))) + +(define format:error-save format:error) + +(define (format:intern-error . args) ;if something goes wrong in format:error + (display "FORMAT: INTERNAL ERROR IN FORMAT:ERROR!") (newline) + (display " format args: ") (write format:args) (newline) + (display " error args: ") (write args) (newline) + (set! format:error format:error-save) + (format:abort)) + +(define (format:format . args) ; the formatter entry + (set! format:args args) + (set! format:arg-pos 0) + (set! format:pos 0) + (if (< (length args) 1) + (format:error "not enough arguments")) + + ;; If the first argument is a string, then that's the format string. + ;; (Scheme->C) + ;; In this case, put the argument list in canonical form. + (let ((args (if (string? (car args)) + (cons #f args) + args))) + ;; Use this canonicalized version when reporting errors. + (set! format:args args) + + (let ((destination (car args)) + (arglist (cdr args))) + (cond + ((or (and (boolean? destination) ; port output + destination) + (output-port? destination) + (number? destination)) + (format:out (cond + ((boolean? destination) (current-output-port)) + ((output-port? destination) destination) + ((number? destination) (current-error-port))) + (car arglist) (cdr arglist))) + ((and (boolean? destination) ; string output + (not destination)) + (call-with-output-string + (lambda (port) (format:out port (car arglist) (cdr arglist))))) + (else + (format:error "illegal destination `~a'" destination)))))) + +(define (format:out port fmt args) ; the output handler for a port + (set! format:port port) ; global port for output routines + (set! format:case-conversion #f) ; modifier case conversion procedure + (set! format:flush-output #f) ; ~! reset + (let ((arg-pos (format:format-work fmt args)) + (arg-len (length args))) + (cond + ((< arg-pos arg-len) + (set! format:arg-pos (+ arg-pos 1)) + (set! format:pos (string-length fmt)) + (format:error "~a superfluous argument~:p" (- arg-len arg-pos))) + ((> arg-pos arg-len) + (set! format:arg-pos (+ arg-len 1)) + (display format:arg-pos) + (format:error "~a missing argument~:p" (- arg-pos arg-len))) + (else + (if format:flush-output (force-output port)) + #t)))) + +(define format:parameter-characters + '(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9 #\- #\+ #\v #\# #\')) + +(define (format:format-work format-string arglist) ; does the formatting work + (letrec + ((format-string-len (string-length format-string)) + (arg-pos 0) ; argument position in arglist + (arg-len (length arglist)) ; number of arguments + (modifier #f) ; 'colon | 'at | 'colon-at | #f + (params '()) ; directive parameter list + (param-value-found #f) ; a directive parameter value found + (conditional-nest 0) ; conditional nesting level + (clause-pos 0) ; last cond. clause beginning char pos + (clause-default #f) ; conditional default clause string + (clauses '()) ; conditional clause string list + (conditional-type #f) ; reflects the contional modifiers + (conditional-arg #f) ; argument to apply the conditional + (iteration-nest 0) ; iteration nesting level + (iteration-pos 0) ; iteration string beginning char pos + (iteration-type #f) ; reflects the iteration modifiers + (max-iterations #f) ; maximum number of iterations + (recursive-pos-save format:pos) + + (next-char ; gets the next char from format-string + (lambda () + (let ((ch (peek-next-char))) + (set! format:pos (+ 1 format:pos)) + ch))) + + (peek-next-char + (lambda () + (if (>= format:pos format-string-len) + (format:error "illegal format string") + (string-ref format-string format:pos)))) + + (one-positive-integer? + (lambda (params) + (cond + ((null? params) #f) + ((and (integer? (car params)) + (>= (car params) 0) + (= (length params) 1)) #t) + (else (format:error "one positive integer parameter expected"))))) + + (next-arg + (lambda () + (if (>= arg-pos arg-len) + (begin + (set! format:arg-pos (+ arg-len 1)) + (format:error "missing argument(s)"))) + (add-arg-pos 1) + (list-ref arglist (- arg-pos 1)))) + + (prev-arg + (lambda () + (add-arg-pos -1) + (if (negative? arg-pos) + (format:error "missing backward argument(s)")) + (list-ref arglist arg-pos))) + + (rest-args + (lambda () + (let loop ((l arglist) (k arg-pos)) ; list-tail definition + (if (= k 0) l (loop (cdr l) (- k 1)))))) + + (add-arg-pos + (lambda (n) + (set! arg-pos (+ n arg-pos)) + (set! format:arg-pos arg-pos))) + + (anychar-dispatch ; dispatches the format-string + (lambda () + (if (>= format:pos format-string-len) + arg-pos ; used for ~? continuance + (let ((char (next-char))) + (cond + ((char=? char #\~) + (set! modifier #f) + (set! params '()) + (set! param-value-found #f) + (tilde-dispatch)) + (else + (if (and (zero? conditional-nest) + (zero? iteration-nest)) + (format:out-char char)) + (anychar-dispatch))))))) + + (tilde-dispatch + (lambda () + (cond + ((>= format:pos format-string-len) + (format:out-str "~") ; tilde at end of string is just output + arg-pos) ; used for ~? continuance + ((and (or (zero? conditional-nest) + (memv (peek-next-char) ; find conditional directives + (append '(#\[ #\] #\; #\: #\@ #\^) + format:parameter-characters))) + (or (zero? iteration-nest) + (memv (peek-next-char) ; find iteration directives + (append '(#\{ #\} #\: #\@ #\^) + format:parameter-characters)))) + (case (char-upcase (next-char)) + + ;; format directives + + ((#\A) ; Any -- for humans + (set! format:read-proof (memq modifier '(colon colon-at))) + (format:out-obj-padded (memq modifier '(at colon-at)) + (next-arg) #f params) + (anychar-dispatch)) + ((#\S) ; Slashified -- for parsers + (set! format:read-proof (memq modifier '(colon colon-at))) + (format:out-obj-padded (memq modifier '(at colon-at)) + (next-arg) #t params) + (anychar-dispatch)) + ((#\D) ; Decimal + (format:out-num-padded modifier (next-arg) params 10) + (anychar-dispatch)) + ((#\X) ; Hexadecimal + (format:out-num-padded modifier (next-arg) params 16) + (anychar-dispatch)) + ((#\O) ; Octal + (format:out-num-padded modifier (next-arg) params 8) + (anychar-dispatch)) + ((#\B) ; Binary + (format:out-num-padded modifier (next-arg) params 2) + (anychar-dispatch)) + ((#\R) + (if (null? params) + (format:out-obj-padded ; Roman, cardinal, ordinal numerals + #f + ((case modifier + ((at) format:num->roman) + ((colon-at) format:num->old-roman) + ((colon) format:num->ordinal) + (else format:num->cardinal)) + (next-arg)) + #f params) + (format:out-num-padded ; any Radix + modifier (next-arg) (cdr params) (car params))) + (anychar-dispatch)) + ((#\F) ; Fixed-format floating-point + (if format:floats + (format:out-fixed modifier (next-arg) params) + (format:out-str (number->string (next-arg)))) + (anychar-dispatch)) + ((#\E) ; Exponential floating-point + (if format:floats + (format:out-expon modifier (next-arg) params) + (format:out-str (number->string (next-arg)))) + (anychar-dispatch)) + ((#\G) ; General floating-point + (if format:floats + (format:out-general modifier (next-arg) params) + (format:out-str (number->string (next-arg)))) + (anychar-dispatch)) + ((#\$) ; Dollars floating-point + (if format:floats + (format:out-dollar modifier (next-arg) params) + (format:out-str (number->string (next-arg)))) + (anychar-dispatch)) + ((#\I) ; Complex numbers + (if (not format:complex-numbers) + (format:error + "complex numbers not supported by this scheme system")) + (let ((z (next-arg))) + (if (not (complex? z)) + (format:error "argument not a complex number")) + (format:out-fixed modifier (real-part z) params) + (format:out-fixed 'at (imag-part z) params) + (format:out-char #\i)) + (anychar-dispatch)) + ((#\C) ; Character + (let ((ch (if (one-positive-integer? params) + (integer->char (car params)) + (next-arg)))) + (if (not (char? ch)) (format:error "~~c expects a character")) + (case modifier + ((at) + (format:out-str (format:char->str ch))) + ((colon) + (let ((c (char->integer ch))) + (if (< c 0) + (set! c (+ c 256))) ; compensate complement impl. + (cond + ((< c #x20) ; assumes that control chars are < #x20 + (format:out-char #\^) + (format:out-char + (integer->char (+ c #x40)))) + ((>= c #x7f) + (format:out-str "#\\") + (format:out-str + (if format:radix-pref + (let ((s (number->string c 8))) + (substring s 2 (string-length s))) + (number->string c 8)))) + (else + (format:out-char ch))))) + (else (format:out-char ch)))) + (anychar-dispatch)) + ((#\P) ; Plural + (if (memq modifier '(colon colon-at)) + (prev-arg)) + (let ((arg (next-arg))) + (if (not (number? arg)) + (format:error "~~p expects a number argument")) + (if (= arg 1) + (if (memq modifier '(at colon-at)) + (format:out-char #\y)) + (if (memq modifier '(at colon-at)) + (format:out-str "ies") + (format:out-char #\s)))) + (anychar-dispatch)) + ((#\~) ; Tilde + (if (one-positive-integer? params) + (format:out-fill (car params) #\~) + (format:out-char #\~)) + (anychar-dispatch)) + ((#\%) ; Newline + (if (one-positive-integer? params) + (format:out-fill (car params) #\newline) + (format:out-char #\newline)) + (set! format:output-col 0) + (anychar-dispatch)) + ((#\&) ; Fresh line + (if (one-positive-integer? params) + (begin + (if (> (car params) 0) + (format:out-fill (- (car params) + (if (> format:output-col 0) 0 1)) + #\newline)) + (set! format:output-col 0)) + (if (> format:output-col 0) + (format:out-char #\newline))) + (anychar-dispatch)) + ((#\_) ; Space character + (if (one-positive-integer? params) + (format:out-fill (car params) #\space) + (format:out-char #\space)) + (anychar-dispatch)) + ((#\/) ; Tabulator character + (if (one-positive-integer? params) + (format:out-fill (car params) slib:tab) + (format:out-char slib:tab)) + (anychar-dispatch)) + ((#\|) ; Page seperator + (if (one-positive-integer? params) + (format:out-fill (car params) slib:form-feed) + (format:out-char slib:form-feed)) + (set! format:output-col 0) + (anychar-dispatch)) + ((#\T) ; Tabulate + (format:tabulate modifier params) + (anychar-dispatch)) + ((#\Y) ; Pretty-print + (require 'pretty-print) + (pretty-print (next-arg) format:port) + (set! format:output-col 0) + (anychar-dispatch)) + ((#\? #\K) ; Indirection (is "~K" in T-Scheme) + (cond + ((memq modifier '(colon colon-at)) + (format:error "illegal modifier in ~~?")) + ((eq? modifier 'at) + (let* ((frmt (next-arg)) + (args (rest-args))) + (add-arg-pos (format:format-work frmt args)))) + (else + (let* ((frmt (next-arg)) + (args (next-arg))) + (format:format-work frmt args)))) + (anychar-dispatch)) + ((#\!) ; Flush output + (set! format:flush-output #t) + (anychar-dispatch)) + ((#\newline) ; Continuation lines + (if (eq? modifier 'at) + (format:out-char #\newline)) + (if (< format:pos format-string-len) + (do ((ch (peek-next-char) (peek-next-char))) + ((or (not (char-whitespace? ch)) + (= format:pos (- format-string-len 1)))) + (if (eq? modifier 'colon) + (format:out-char (next-char)) + (next-char)))) + (anychar-dispatch)) + ((#\*) ; Argument jumping + (case modifier + ((colon) ; jump backwards + (if (one-positive-integer? params) + (do ((i 0 (+ i 1))) + ((= i (car params))) + (prev-arg)) + (prev-arg))) + ((at) ; jump absolute + (set! arg-pos (if (one-positive-integer? params) + (car params) 0))) + ((colon-at) + (format:error "illegal modifier `:@' in ~~* directive")) + (else ; jump forward + (if (one-positive-integer? params) + (do ((i 0 (+ i 1))) + ((= i (car params))) + (next-arg)) + (next-arg)))) + (anychar-dispatch)) + ((#\() ; Case conversion begin + (set! format:case-conversion + (case modifier + ((at) format:string-capitalize-first) + ((colon) string-capitalize) + ((colon-at) string-upcase) + (else string-downcase))) + (anychar-dispatch)) + ((#\)) ; Case conversion end + (if (not format:case-conversion) + (format:error "missing ~~(")) + (set! format:case-conversion #f) + (anychar-dispatch)) + ((#\[) ; Conditional begin + (set! conditional-nest (+ conditional-nest 1)) + (cond + ((= conditional-nest 1) + (set! clause-pos format:pos) + (set! clause-default #f) + (set! clauses '()) + (set! conditional-type + (case modifier + ((at) 'if-then) + ((colon) 'if-else-then) + ((colon-at) (format:error "illegal modifier in ~~[")) + (else 'num-case))) + (set! conditional-arg + (if (one-positive-integer? params) + (car params) + (next-arg))))) + (anychar-dispatch)) + ((#\;) ; Conditional separator + (if (zero? conditional-nest) + (format:error "~~; not in ~~[~~] conditional")) + (if (not (null? params)) + (format:error "no parameter allowed in ~~;")) + (if (= conditional-nest 1) + (let ((clause-str + (cond + ((eq? modifier 'colon) + (set! clause-default #t) + (substring format-string clause-pos + (- format:pos 3))) + ((memq modifier '(at colon-at)) + (format:error "illegal modifier in ~~;")) + (else + (substring format-string clause-pos + (- format:pos 2)))))) + (set! clauses (append clauses (list clause-str))) + (set! clause-pos format:pos))) + (anychar-dispatch)) + ((#\]) ; Conditional end + (if (zero? conditional-nest) (format:error "missing ~~[")) + (set! conditional-nest (- conditional-nest 1)) + (if modifier + (format:error "no modifier allowed in ~~]")) + (if (not (null? params)) + (format:error "no parameter allowed in ~~]")) + (cond + ((zero? conditional-nest) + (let ((clause-str (substring format-string clause-pos + (- format:pos 2)))) + (if clause-default + (set! clause-default clause-str) + (set! clauses (append clauses (list clause-str))))) + (case conditional-type + ((if-then) + (if conditional-arg + (format:format-work (car clauses) + (list conditional-arg)))) + ((if-else-then) + (add-arg-pos + (format:format-work (if conditional-arg + (cadr clauses) + (car clauses)) + (rest-args)))) + ((num-case) + (if (or (not (integer? conditional-arg)) + (< conditional-arg 0)) + (format:error "argument not a positive integer")) + (if (not (and (>= conditional-arg (length clauses)) + (not clause-default))) + (add-arg-pos + (format:format-work + (if (>= conditional-arg (length clauses)) + clause-default + (list-ref clauses conditional-arg)) + (rest-args)))))))) + (anychar-dispatch)) + ((#\{) ; Iteration begin + (set! iteration-nest (+ iteration-nest 1)) + (cond + ((= iteration-nest 1) + (set! iteration-pos format:pos) + (set! iteration-type + (case modifier + ((at) 'rest-args) + ((colon) 'sublists) + ((colon-at) 'rest-sublists) + (else 'list))) + (set! max-iterations (if (one-positive-integer? params) + (car params) #f)))) + (anychar-dispatch)) + ((#\}) ; Iteration end + (if (zero? iteration-nest) (format:error "missing ~~{")) + (set! iteration-nest (- iteration-nest 1)) + (case modifier + ((colon) + (if (not max-iterations) (set! max-iterations 1))) + ((colon-at at) (format:error "illegal modifier")) + (else (if (not max-iterations) + (set! max-iterations format:max-iterations)))) + (if (not (null? params)) + (format:error "no parameters allowed in ~~}")) + (if (zero? iteration-nest) + (let ((iteration-str + (substring format-string iteration-pos + (- format:pos (if modifier 3 2))))) + (if (string=? iteration-str "") + (set! iteration-str (next-arg))) + (case iteration-type + ((list) + (let ((args (next-arg)) + (args-len 0)) + (if (not (list? args)) + (format:error "expected a list argument")) + (set! args-len (length args)) + (do ((arg-pos 0 (+ arg-pos + (format:format-work + iteration-str + (list-tail args arg-pos)))) + (i 0 (+ i 1))) + ((or (>= arg-pos args-len) + (and format:iteration-bounded + (>= i max-iterations))))))) + ((sublists) + (let ((args (next-arg)) + (args-len 0)) + (if (not (list? args)) + (format:error "expected a list argument")) + (set! args-len (length args)) + (do ((arg-pos 0 (+ arg-pos 1))) + ((or (>= arg-pos args-len) + (and format:iteration-bounded + (>= arg-pos max-iterations)))) + (let ((sublist (list-ref args arg-pos))) + (if (not (list? sublist)) + (format:error + "expected a list of lists argument")) + (format:format-work iteration-str sublist))))) + ((rest-args) + (let* ((args (rest-args)) + (args-len (length args)) + (usedup-args + (do ((arg-pos 0 (+ arg-pos + (format:format-work + iteration-str + (list-tail + args arg-pos)))) + (i 0 (+ i 1))) + ((or (>= arg-pos args-len) + (and format:iteration-bounded + (>= i max-iterations))) + arg-pos)))) + (add-arg-pos usedup-args))) + ((rest-sublists) + (let* ((args (rest-args)) + (args-len (length args)) + (usedup-args + (do ((arg-pos 0 (+ arg-pos 1))) + ((or (>= arg-pos args-len) + (and format:iteration-bounded + (>= arg-pos max-iterations))) + arg-pos) + (let ((sublist (list-ref args arg-pos))) + (if (not (list? sublist)) + (format:error "expected list arguments")) + (format:format-work iteration-str sublist))))) + (add-arg-pos usedup-args))) + (else (format:error "internal error in ~~}"))))) + (anychar-dispatch)) + ((#\^) ; Up and out + (let* ((continue + (cond + ((not (null? params)) + (not + (case (length params) + ((1) (zero? (car params))) + ((2) (= (list-ref params 0) (list-ref params 1))) + ((3) (<= (list-ref params 0) + (list-ref params 1) + (list-ref params 2))) + (else (format:error "too much parameters"))))) + (format:case-conversion ; if conversion stop conversion + (set! format:case-conversion string-copy) #t) + ((= iteration-nest 1) #t) + ((= conditional-nest 1) #t) + ((>= arg-pos arg-len) + (set! format:pos format-string-len) #f) + (else #t)))) + (if continue + (anychar-dispatch)))) + + ;; format directive modifiers and parameters + + ((#\@) ; `@' modifier + (if (memq modifier '(at colon-at)) + (format:error "double `@' modifier")) + (set! modifier (if (eq? modifier 'colon) 'colon-at 'at)) + (tilde-dispatch)) + ((#\:) ; `:' modifier + (if (memq modifier '(colon colon-at)) + (format:error "double `:' modifier")) + (set! modifier (if (eq? modifier 'at) 'colon-at 'colon)) + (tilde-dispatch)) + ((#\') ; Character parameter + (if modifier (format:error "misplaced modifier")) + (set! params (append params (list (char->integer (next-char))))) + (set! param-value-found #t) + (tilde-dispatch)) + ((#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9 #\- #\+) ; num. paramtr + (if modifier (format:error "misplaced modifier")) + (let ((num-str-beg (- format:pos 1)) + (num-str-end format:pos)) + (do ((ch (peek-next-char) (peek-next-char))) + ((not (char-numeric? ch))) + (next-char) + (set! num-str-end (+ 1 num-str-end))) + (set! params + (append params + (list (string->number + (substring format-string + num-str-beg + num-str-end)))))) + (set! param-value-found #t) + (tilde-dispatch)) + ((#\V) ; Variable parameter from next argum. + (if modifier (format:error "misplaced modifier")) + (set! params (append params (list (next-arg)))) + (set! param-value-found #t) + (tilde-dispatch)) + ((#\#) ; Parameter is number of remaining args + (if modifier (format:error "misplaced modifier")) + (set! params (append params (list (length (rest-args))))) + (set! param-value-found #t) + (tilde-dispatch)) + ((#\,) ; Parameter separators + (if modifier (format:error "misplaced modifier")) + (if (not param-value-found) + (set! params (append params '(#f)))) ; append empty paramtr + (set! param-value-found #f) + (tilde-dispatch)) + ((#\Q) ; Inquiry messages + (if (eq? modifier 'colon) + (format:out-str format:version) + (let ((nl (string #\newline))) + (format:out-str + (string-append + "SLIB Common LISP format version " format:version nl + " (C) copyright 1992-1994 by Dirk Lutzebaeck" nl + " please send bug reports to `lutzeb@cs.tu-berlin.de'" + nl)))) + (anychar-dispatch)) + (else ; Unknown tilde directive + (format:error "unknown control character `~c'" + (string-ref format-string (- format:pos 1)))))) + (else (anychar-dispatch)))))) ; in case of conditional + + (set! format:pos 0) + (set! format:arg-pos 0) + (anychar-dispatch) ; start the formatting + (set! format:pos recursive-pos-save) + arg-pos)) ; return the position in the arg. list + +;; format:obj->str returns a R4RS representation as a string of an arbitrary +;; scheme object. +;; First parameter is the object, second parameter is a boolean if the +;; representation should be slashified as `write' does. +;; It uses format:char->str which converts a character into +;; a slashified string as `write' does and which is implementation dependent. +;; It uses format:iobj->str to print out internal objects as +;; quoted strings so that the output can always be processed by (read) + +(define (format:obj->str obj slashify) + (cond + ((string? obj) + (if slashify + (let ((obj-len (string-length obj))) + (string-append + "\"" + (let loop ((i 0) (j 0)) ; taken from Marc Feeley's pp.scm + (if (= j obj-len) + (string-append (substring obj i j) "\"") + (let ((c (string-ref obj j))) + (if (or (char=? c #\\) + (char=? c #\")) + (string-append (substring obj i j) "\\" + (loop j (+ j 1))) + (loop i (+ j 1)))))))) + obj)) + + ((boolean? obj) (if obj "#t" "#f")) + + ((number? obj) (number->string obj)) + + ((symbol? obj) + (if format:symbol-case-conv + (format:symbol-case-conv (symbol->string obj)) + (symbol->string obj))) + + ((char? obj) + (if slashify + (format:char->str obj) + (string obj))) + + ((null? obj) "()") + + ((input-port? obj) + (format:iobj->str obj)) + + ((output-port? obj) + (format:iobj->str obj)) + + ((list? obj) + (string-append "(" + (let loop ((obj-list obj)) + (if (null? (cdr obj-list)) + (format:obj->str (car obj-list) #t) + (string-append + (format:obj->str (car obj-list) #t) + " " + (loop (cdr obj-list))))) + ")")) + + ((pair? obj) + (string-append "(" + (format:obj->str (car obj) #t) + " . " + (format:obj->str (cdr obj) #t) + ")")) + + ((vector? obj) + (string-append "#" (format:obj->str (vector->list obj) #t))) + + (else ; only objects with an #<...> + (format:iobj->str obj)))) ; representation should fall in here + +;; format:iobj->str reveals the implementation dependent representation of +;; #<...> objects with the use of display and call-with-output-string. +;; If format:read-proof is set to #t the resulting string is additionally +;; set into string quotes. + +(define format:read-proof #f) + +(define (format:iobj->str iobj) + (if (or format:read-proof + format:iobj-case-conv) + (string-append + (if format:read-proof "\"" "") + (if format:iobj-case-conv + (format:iobj-case-conv + (call-with-output-string (lambda (p) (display iobj p)))) + (call-with-output-string (lambda (p) (display iobj p)))) + (if format:read-proof "\"" "")) + (call-with-output-string (lambda (p) (display iobj p))))) + + +;; format:char->str converts a character into a slashified string as +;; done by `write'. The procedure is dependent on the integer +;; representation of characters and assumes a character number according to +;; the ASCII character set. + +(define (format:char->str ch) + (let ((int-rep (char->integer ch))) + (if (< int-rep 0) ; if chars are [-128...+127] + (set! int-rep (+ int-rep 256))) + (string-append + "#\\" + (cond + ((char=? ch #\newline) "newline") + ((and (>= int-rep 0) (<= int-rep 32)) + (vector-ref format:ascii-non-printable-charnames int-rep)) + ((= int-rep 127) "del") + ((>= int-rep 128) ; octal representation + (if format:radix-pref + (let ((s (number->string int-rep 8))) + (substring s 2 (string-length s))) + (number->string int-rep 8))) + (else (string ch)))))) + +(define format:space-ch (char->integer #\space)) +(define format:zero-ch (char->integer #\0)) + +(define (format:par pars length index default name) + (if (> length index) + (let ((par (list-ref pars index))) + (if par + (if name + (if (< par 0) + (format:error + "~s parameter must be a positive integer" name) + par) + par) + default)) + default)) + +(define (format:out-obj-padded pad-left obj slashify pars) + (if (null? pars) + (format:out-str (format:obj->str obj slashify)) + (let ((l (length pars))) + (let ((mincol (format:par pars l 0 0 "mincol")) + (colinc (format:par pars l 1 1 "colinc")) + (minpad (format:par pars l 2 0 "minpad")) + (padchar (integer->char + (format:par pars l 3 format:space-ch #f))) + (objstr (format:obj->str obj slashify))) + (if (not pad-left) + (format:out-str objstr)) + (do ((objstr-len (string-length objstr)) + (i minpad (+ i colinc))) + ((>= (+ objstr-len i) mincol) + (format:out-fill i padchar))) + (if pad-left + (format:out-str objstr)))))) + +(define (format:out-num-padded modifier number pars radix) + (if (not (integer? number)) (format:error "argument not an integer")) + (let ((numstr (number->string number radix))) + (if (and format:radix-pref (not (= radix 10))) + (set! numstr (substring numstr 2 (string-length numstr)))) + (if (and (null? pars) (not modifier)) + (format:out-str numstr) + (let ((l (length pars)) + (numstr-len (string-length numstr))) + (let ((mincol (format:par pars l 0 #f "mincol")) + (padchar (integer->char + (format:par pars l 1 format:space-ch #f))) + (commachar (integer->char + (format:par pars l 2 (char->integer #\,) #f))) + (commawidth (format:par pars l 3 3 "commawidth"))) + (if mincol + (let ((numlen numstr-len)) ; calc. the output len of number + (if (and (memq modifier '(at colon-at)) (> number 0)) + (set! numlen (+ numlen 1))) + (if (memq modifier '(colon colon-at)) + (set! numlen (+ (quotient (- numstr-len + (if (< number 0) 2 1)) + commawidth) + numlen))) + (if (> mincol numlen) + (format:out-fill (- mincol numlen) padchar)))) + (if (and (memq modifier '(at colon-at)) + (> number 0)) + (format:out-char #\+)) + (if (memq modifier '(colon colon-at)) ; insert comma character + (let ((start (remainder numstr-len commawidth)) + (ns (if (< number 0) 1 0))) + (format:out-substr numstr 0 start) + (do ((i start (+ i commawidth))) + ((>= i numstr-len)) + (if (> i ns) + (format:out-char commachar)) + (format:out-substr numstr i (+ i commawidth)))) + (format:out-str numstr))))))) + +(define (format:tabulate modifier pars) + (let ((l (length pars))) + (let ((colnum (format:par pars l 0 1 "colnum")) + (colinc (format:par pars l 1 1 "colinc")) + (padch (integer->char (format:par pars l 2 format:space-ch #f)))) + (case modifier + ((colon colon-at) + (format:error "unsupported modifier for ~~t")) + ((at) ; relative tabulation + (format:out-fill + (if (= colinc 0) + colnum ; colnum = colrel + (do ((c 0 (+ c colinc)) + (col (+ format:output-col colnum))) + ((>= c col) + (- c format:output-col)))) + padch)) + (else ; absolute tabulation + (format:out-fill + (cond + ((< format:output-col colnum) + (- colnum format:output-col)) + ((= colinc 0) + 0) + (else + (do ((c colnum (+ c colinc))) + ((>= c format:output-col) + (- c format:output-col))))) + padch)))))) + + +;; roman numerals (from dorai@cs.rice.edu). + +(define format:roman-alist + '((1000 #\M) (500 #\D) (100 #\C) (50 #\L) + (10 #\X) (5 #\V) (1 #\I))) + +(define format:roman-boundary-values + '(100 100 10 10 1 1 #f)) + +(define format:num->old-roman + (lambda (n) + (if (and (integer? n) (>= n 1)) + (let loop ((n n) + (romans format:roman-alist) + (s '())) + (if (null? romans) (list->string (reverse s)) + (let ((roman-val (caar romans)) + (roman-dgt (cadar romans))) + (do ((q (quotient n roman-val) (- q 1)) + (s s (cons roman-dgt s))) + ((= q 0) + (loop (remainder n roman-val) + (cdr romans) s)))))) + (format:error "only positive integers can be romanized")))) + +(define format:num->roman + (lambda (n) + (if (and (integer? n) (> n 0)) + (let loop ((n n) + (romans format:roman-alist) + (boundaries format:roman-boundary-values) + (s '())) + (if (null? romans) + (list->string (reverse s)) + (let ((roman-val (caar romans)) + (roman-dgt (cadar romans)) + (bdry (car boundaries))) + (let loop2 ((q (quotient n roman-val)) + (r (remainder n roman-val)) + (s s)) + (if (= q 0) + (if (and bdry (>= r (- roman-val bdry))) + (loop (remainder r bdry) (cdr romans) + (cdr boundaries) + (cons roman-dgt + (append + (cdr (assv bdry romans)) + s))) + (loop r (cdr romans) (cdr boundaries) s)) + (loop2 (- q 1) r (cons roman-dgt s))))))) + (format:error "only positive integers can be romanized")))) + +;; cardinals & ordinals (from dorai@cs.rice.edu) + +(define format:cardinal-ones-list + '(#f "one" "two" "three" "four" "five" + "six" "seven" "eight" "nine" "ten" "eleven" "twelve" "thirteen" + "fourteen" "fifteen" "sixteen" "seventeen" "eighteen" + "nineteen")) + +(define format:cardinal-tens-list + '(#f #f "twenty" "thirty" "forty" "fifty" "sixty" "seventy" "eighty" + "ninety")) + +(define format:num->cardinal999 + (lambda (n) + ;this procedure is inspired by the Bruno Haible's CLisp + ;function format-small-cardinal, which converts numbers + ;in the range 1 to 999, and is used for converting each + ;thousand-block in a larger number + (let* ((hundreds (quotient n 100)) + (tens+ones (remainder n 100)) + (tens (quotient tens+ones 10)) + (ones (remainder tens+ones 10))) + (append + (if (> hundreds 0) + (append + (string->list + (list-ref format:cardinal-ones-list hundreds)) + (string->list" hundred") + (if (> tens+ones 0) '(#\space) '())) + '()) + (if (< tens+ones 20) + (if (> tens+ones 0) + (string->list + (list-ref format:cardinal-ones-list tens+ones)) + '()) + (append + (string->list + (list-ref format:cardinal-tens-list tens)) + (if (> ones 0) + (cons #\- + (string->list + (list-ref format:cardinal-ones-list ones))) + '()))))))) + +(define format:cardinal-thousand-block-list + '("" " thousand" " million" " billion" " trillion" " quadrillion" + " quintillion" " sextillion" " septillion" " octillion" " nonillion" + " decillion" " undecillion" " duodecillion" " tredecillion" + " quattuordecillion" " quindecillion" " sexdecillion" " septendecillion" + " octodecillion" " novemdecillion" " vigintillion")) + +(define format:num->cardinal + (lambda (n) + (cond ((not (integer? n)) + (format:error + "only integers can be converted to English cardinals")) + ((= n 0) "zero") + ((< n 0) (string-append "minus " (format:num->cardinal (- n)))) + (else + (let ((power3-word-limit + (length format:cardinal-thousand-block-list))) + (let loop ((n n) + (power3 0) + (s '())) + (if (= n 0) + (list->string s) + (let ((n-before-block (quotient n 1000)) + (n-after-block (remainder n 1000))) + (loop n-before-block + (+ power3 1) + (if (> n-after-block 0) + (append + (if (> n-before-block 0) + (string->list ", ") '()) + (format:num->cardinal999 n-after-block) + (if (< power3 power3-word-limit) + (string->list + (list-ref + format:cardinal-thousand-block-list + power3)) + (append + (string->list " times ten to the ") + (string->list + (format:num->ordinal + (* power3 3))) + (string->list " power"))) + s) + s)))))))))) + +(define format:ordinal-ones-list + '(#f "first" "second" "third" "fourth" "fifth" + "sixth" "seventh" "eighth" "ninth" "tenth" "eleventh" "twelfth" + "thirteenth" "fourteenth" "fifteenth" "sixteenth" "seventeenth" + "eighteenth" "nineteenth")) + +(define format:ordinal-tens-list + '(#f #f "twentieth" "thirtieth" "fortieth" "fiftieth" "sixtieth" + "seventieth" "eightieth" "ninetieth")) + +(define format:num->ordinal + (lambda (n) + (cond ((not (integer? n)) + (format:error + "only integers can be converted to English ordinals")) + ((= n 0) "zeroth") + ((< n 0) (string-append "minus " (format:num->ordinal (- n)))) + (else + (let ((hundreds (quotient n 100)) + (tens+ones (remainder n 100))) + (string-append + (if (> hundreds 0) + (string-append + (format:num->cardinal (* hundreds 100)) + (if (= tens+ones 0) "th" " ")) + "") + (if (= tens+ones 0) "" + (if (< tens+ones 20) + (list-ref format:ordinal-ones-list tens+ones) + (let ((tens (quotient tens+ones 10)) + (ones (remainder tens+ones 10))) + (if (= ones 0) + (list-ref format:ordinal-tens-list tens) + (string-append + (list-ref format:cardinal-tens-list tens) + "-" + (list-ref format:ordinal-ones-list ones)))) + )))))))) + +;; format fixed flonums (~F) + +(define (format:out-fixed modifier number pars) + (if (not (or (number? number) (string? number))) + (format:error "argument is not a number or a number string")) + + (let ((l (length pars))) + (let ((width (format:par pars l 0 #f "width")) + (digits (format:par pars l 1 #f "digits")) + (scale (format:par pars l 2 0 #f)) + (overch (format:par pars l 3 #f #f)) + (padch (format:par pars l 4 format:space-ch #f))) + + (if digits + + (begin ; fixed precision + (format:parse-float + (if (string? number) number (number->string number)) #t scale) + (if (<= (- format:fn-len format:fn-dot) digits) + (format:fn-zfill #f (- digits (- format:fn-len format:fn-dot))) + (format:fn-round digits)) + (if width + (let ((numlen (+ format:fn-len 1))) + (if (or (not format:fn-pos?) (eq? modifier 'at)) + (set! numlen (+ numlen 1))) + (if (and (= format:fn-dot 0) (> width (+ digits 1))) + (set! numlen (+ numlen 1))) + (if (< numlen width) + (format:out-fill (- width numlen) (integer->char padch))) + (if (and overch (> numlen width)) + (format:out-fill width (integer->char overch)) + (format:fn-out modifier (> width (+ digits 1))))) + (format:fn-out modifier #t))) + + (begin ; free precision + (format:parse-float + (if (string? number) number (number->string number)) #t scale) + (format:fn-strip) + (if width + (let ((numlen (+ format:fn-len 1))) + (if (or (not format:fn-pos?) (eq? modifier 'at)) + (set! numlen (+ numlen 1))) + (if (= format:fn-dot 0) + (set! numlen (+ numlen 1))) + (if (< numlen width) + (format:out-fill (- width numlen) (integer->char padch))) + (if (> numlen width) ; adjust precision if possible + (let ((dot-index (- numlen + (- format:fn-len format:fn-dot)))) + (if (> dot-index width) + (if overch ; numstr too big for required width + (format:out-fill width (integer->char overch)) + (format:fn-out modifier #t)) + (begin + (format:fn-round (- width dot-index)) + (format:fn-out modifier #t)))) + (format:fn-out modifier #t))) + (format:fn-out modifier #t))))))) + +;; format exponential flonums (~E) + +(define (format:out-expon modifier number pars) + (if (not (or (number? number) (string? number))) + (format:error "argument is not a number")) + + (let ((l (length pars))) + (let ((width (format:par pars l 0 #f "width")) + (digits (format:par pars l 1 #f "digits")) + (edigits (format:par pars l 2 #f "exponent digits")) + (scale (format:par pars l 3 1 #f)) + (overch (format:par pars l 4 #f #f)) + (padch (format:par pars l 5 format:space-ch #f)) + (expch (format:par pars l 6 #f #f))) + + (if digits ; fixed precision + + (let ((digits (if (> scale 0) + (if (< scale (+ digits 2)) + (+ (- digits scale) 1) + 0) + digits))) + (format:parse-float + (if (string? number) number (number->string number)) #f scale) + (if (<= (- format:fn-len format:fn-dot) digits) + (format:fn-zfill #f (- digits (- format:fn-len format:fn-dot))) + (format:fn-round digits)) + (if width + (if (and edigits overch (> format:en-len edigits)) + (format:out-fill width (integer->char overch)) + (let ((numlen (+ format:fn-len 3))) ; .E+ + (if (or (not format:fn-pos?) (eq? modifier 'at)) + (set! numlen (+ numlen 1))) + (if (and (= format:fn-dot 0) (> width (+ digits 1))) + (set! numlen (+ numlen 1))) + (set! numlen + (+ numlen + (if (and edigits (>= edigits format:en-len)) + edigits + format:en-len))) + (if (< numlen width) + (format:out-fill (- width numlen) + (integer->char padch))) + (if (and overch (> numlen width)) + (format:out-fill width (integer->char overch)) + (begin + (format:fn-out modifier (> width (- numlen 1))) + (format:en-out edigits expch))))) + (begin + (format:fn-out modifier #t) + (format:en-out edigits expch)))) + + (begin ; free precision + (format:parse-float + (if (string? number) number (number->string number)) #f scale) + (format:fn-strip) + (if width + (if (and edigits overch (> format:en-len edigits)) + (format:out-fill width (integer->char overch)) + (let ((numlen (+ format:fn-len 3))) ; .E+ + (if (or (not format:fn-pos?) (eq? modifier 'at)) + (set! numlen (+ numlen 1))) + (if (= format:fn-dot 0) + (set! numlen (+ numlen 1))) + (set! numlen + (+ numlen + (if (and edigits (>= edigits format:en-len)) + edigits + format:en-len))) + (if (< numlen width) + (format:out-fill (- width numlen) + (integer->char padch))) + (if (> numlen width) ; adjust precision if possible + (let ((f (- format:fn-len format:fn-dot))) ; fract len + (if (> (- numlen f) width) + (if overch ; numstr too big for required width + (format:out-fill width + (integer->char overch)) + (begin + (format:fn-out modifier #t) + (format:en-out edigits expch))) + (begin + (format:fn-round (+ (- f numlen) width)) + (format:fn-out modifier #t) + (format:en-out edigits expch)))) + (begin + (format:fn-out modifier #t) + (format:en-out edigits expch))))) + (begin + (format:fn-out modifier #t) + (format:en-out edigits expch)))))))) + +;; format general flonums (~G) + +(define (format:out-general modifier number pars) + (if (not (or (number? number) (string? number))) + (format:error "argument is not a number or a number string")) + + (let ((l (length pars))) + (let ((width (if (> l 0) (list-ref pars 0) #f)) + (digits (if (> l 1) (list-ref pars 1) #f)) + (edigits (if (> l 2) (list-ref pars 2) #f)) + (overch (if (> l 4) (list-ref pars 4) #f)) + (padch (if (> l 5) (list-ref pars 5) #f))) + (format:parse-float + (if (string? number) number (number->string number)) #t 0) + (format:fn-strip) + (let* ((ee (if edigits (+ edigits 2) 4)) ; for the following algorithm + (ww (if width (- width ee) #f)) ; see Steele's CL book p.395 + (n (if (= format:fn-dot 0) ; number less than (abs 1.0) ? + (- (format:fn-zlead)) + format:fn-dot)) + (d (if digits + digits + (max format:fn-len (min n 7)))) ; q = format:fn-len + (dd (- d n))) + (if (<= 0 dd d) + (begin + (format:out-fixed modifier number (list ww dd #f overch padch)) + (format:out-fill ee #\space)) ;~@T not implemented yet + (format:out-expon modifier number pars)))))) + +;; format dollar flonums (~$) + +(define (format:out-dollar modifier number pars) + (if (not (or (number? number) (string? number))) + (format:error "argument is not a number or a number string")) + + (let ((l (length pars))) + (let ((digits (format:par pars l 0 2 "digits")) + (mindig (format:par pars l 1 1 "mindig")) + (width (format:par pars l 2 0 "width")) + (padch (format:par pars l 3 format:space-ch #f))) + + (format:parse-float + (if (string? number) number (number->string number)) #t 0) + (if (<= (- format:fn-len format:fn-dot) digits) + (format:fn-zfill #f (- digits (- format:fn-len format:fn-dot))) + (format:fn-round digits)) + (let ((numlen (+ format:fn-len 1))) + (if (or (not format:fn-pos?) (memq modifier '(at colon-at))) + (set! numlen (+ numlen 1))) + (if (and mindig (> mindig format:fn-dot)) + (set! numlen (+ numlen (- mindig format:fn-dot)))) + (if (and (= format:fn-dot 0) (not mindig)) + (set! numlen (+ numlen 1))) + (if (< numlen width) + (case modifier + ((colon) + (if (not format:fn-pos?) + (format:out-char #\-)) + (format:out-fill (- width numlen) (integer->char padch))) + ((at) + (format:out-fill (- width numlen) (integer->char padch)) + (format:out-char (if format:fn-pos? #\+ #\-))) + ((colon-at) + (format:out-char (if format:fn-pos? #\+ #\-)) + (format:out-fill (- width numlen) (integer->char padch))) + (else + (format:out-fill (- width numlen) (integer->char padch)) + (if (not format:fn-pos?) + (format:out-char #\-)))) + (if format:fn-pos? + (if (memq modifier '(at colon-at)) (format:out-char #\+)) + (format:out-char #\-)))) + (if (and mindig (> mindig format:fn-dot)) + (format:out-fill (- mindig format:fn-dot) #\0)) + (if (and (= format:fn-dot 0) (not mindig)) + (format:out-char #\0)) + (format:out-substr format:fn-str 0 format:fn-dot) + (format:out-char #\.) + (format:out-substr format:fn-str format:fn-dot format:fn-len)))) + +; the flonum buffers + +(define format:fn-max 200) ; max. number of number digits +(define format:fn-str (make-string format:fn-max)) ; number buffer +(define format:fn-len 0) ; digit length of number +(define format:fn-dot #f) ; dot position of number +(define format:fn-pos? #t) ; number positive? +(define format:en-max 10) ; max. number of exponent digits +(define format:en-str (make-string format:en-max)) ; exponent buffer +(define format:en-len 0) ; digit length of exponent +(define format:en-pos? #t) ; exponent positive? + +(define (format:parse-float num-str fixed? scale) + (set! format:fn-pos? #t) + (set! format:fn-len 0) + (set! format:fn-dot #f) + (set! format:en-pos? #t) + (set! format:en-len 0) + (do ((i 0 (+ i 1)) + (left-zeros 0) + (mantissa? #t) + (all-zeros? #t) + (num-len (string-length num-str)) + (c #f)) ; current exam. character in num-str + ((= i num-len) + (if (not format:fn-dot) + (set! format:fn-dot format:fn-len)) + + (if all-zeros? + (begin + (set! left-zeros 0) + (set! format:fn-dot 0) + (set! format:fn-len 1))) + + ;; now format the parsed values according to format's need + + (if fixed? + + (begin ; fixed format m.nnn or .nnn + (if (and (> left-zeros 0) (> format:fn-dot 0)) + (if (> format:fn-dot left-zeros) + (begin ; norm 0{0}nn.mm to nn.mm + (format:fn-shiftleft left-zeros) + (set! left-zeros 0) + (set! format:fn-dot (- format:fn-dot left-zeros))) + (begin ; normalize 0{0}.nnn to .nnn + (format:fn-shiftleft format:fn-dot) + (set! left-zeros (- left-zeros format:fn-dot)) + (set! format:fn-dot 0)))) + (if (or (not (= scale 0)) (> format:en-len 0)) + (let ((shift (+ scale (format:en-int)))) + (cond + (all-zeros? #t) + ((> (+ format:fn-dot shift) format:fn-len) + (format:fn-zfill + #f (- shift (- format:fn-len format:fn-dot))) + (set! format:fn-dot format:fn-len)) + ((< (+ format:fn-dot shift) 0) + (format:fn-zfill #t (- (- shift) format:fn-dot)) + (set! format:fn-dot 0)) + (else + (if (> left-zeros 0) + (if (<= left-zeros shift) ; shift always > 0 here + (format:fn-shiftleft shift) ; shift out 0s + (begin + (format:fn-shiftleft left-zeros) + (set! format:fn-dot (- shift left-zeros)))) + (set! format:fn-dot (+ format:fn-dot shift)))))))) + + (let ((negexp ; expon format m.nnnEee + (if (> left-zeros 0) + (- left-zeros format:fn-dot -1) + (if (= format:fn-dot 0) 1 0)))) + (if (> left-zeros 0) + (begin ; normalize 0{0}.nnn to n.nn + (format:fn-shiftleft left-zeros) + (set! format:fn-dot 1)) + (if (= format:fn-dot 0) + (set! format:fn-dot 1))) + (format:en-set (- (+ (- format:fn-dot scale) (format:en-int)) + negexp)) + (cond + (all-zeros? + (format:en-set 0) + (set! format:fn-dot 1)) + ((< scale 0) ; leading zero + (format:fn-zfill #t (- scale)) + (set! format:fn-dot 0)) + ((> scale format:fn-dot) + (format:fn-zfill #f (- scale format:fn-dot)) + (set! format:fn-dot scale)) + (else + (set! format:fn-dot scale))))) + #t) + + ;; do body + (set! c (string-ref num-str i)) ; parse the output of number->string + (cond ; which can be any valid number + ((char-numeric? c) ; representation of R4RS except + (if mantissa? ; complex numbers + (begin + (if (char=? c #\0) + (if all-zeros? + (set! left-zeros (+ left-zeros 1))) + (begin + (set! all-zeros? #f))) + (string-set! format:fn-str format:fn-len c) + (set! format:fn-len (+ format:fn-len 1))) + (begin + (string-set! format:en-str format:en-len c) + (set! format:en-len (+ format:en-len 1))))) + ((or (char=? c #\-) (char=? c #\+)) + (if mantissa? + (set! format:fn-pos? (char=? c #\+)) + (set! format:en-pos? (char=? c #\+)))) + ((char=? c #\.) + (set! format:fn-dot format:fn-len)) + ((char=? c #\e) + (set! mantissa? #f)) + ((char=? c #\E) + (set! mantissa? #f)) + ((char-whitespace? c) #t) + ((char=? c #\d) #t) ; decimal radix prefix + ((char=? c #\#) #t) + (else + (format:error "illegal character `~c' in number->string" c))))) + +(define (format:en-int) ; convert exponent string to integer + (if (= format:en-len 0) + 0 + (do ((i 0 (+ i 1)) + (n 0)) + ((= i format:en-len) + (if format:en-pos? + n + (- n))) + (set! n (+ (* n 10) (- (char->integer (string-ref format:en-str i)) + format:zero-ch)))))) + +(define (format:en-set en) ; set exponent string number + (set! format:en-len 0) + (set! format:en-pos? (>= en 0)) + (let ((en-str (number->string en))) + (do ((i 0 (+ i 1)) + (en-len (string-length en-str)) + (c #f)) + ((= i en-len)) + (set! c (string-ref en-str i)) + (if (char-numeric? c) + (begin + (string-set! format:en-str format:en-len c) + (set! format:en-len (+ format:en-len 1))))))) + +(define (format:fn-zfill left? n) ; fill current number string with 0s + (if (> (+ n format:fn-len) format:fn-max) ; from the left or right + (format:error "number is too long to format (enlarge format:fn-max)")) + (set! format:fn-len (+ format:fn-len n)) + (if left? + (do ((i format:fn-len (- i 1))) ; fill n 0s to left + ((< i 0)) + (string-set! format:fn-str i + (if (< i n) + #\0 + (string-ref format:fn-str (- i n))))) + (do ((i (- format:fn-len n) (+ i 1))) ; fill n 0s to the right + ((= i format:fn-len)) + (string-set! format:fn-str i #\0)))) + +(define (format:fn-shiftleft n) ; shift left current number n positions + (if (> n format:fn-len) + (format:error "internal error in format:fn-shiftleft (~d,~d)" + n format:fn-len)) + (do ((i n (+ i 1))) + ((= i format:fn-len) + (set! format:fn-len (- format:fn-len n))) + (string-set! format:fn-str (- i n) (string-ref format:fn-str i)))) + +(define (format:fn-round digits) ; round format:fn-str + (set! digits (+ digits format:fn-dot)) + (do ((i digits (- i 1)) ; "099",2 -> "10" + (c 5)) ; "023",2 -> "02" + ((or (= c 0) (< i 0)) ; "999",2 -> "100" + (if (= c 1) ; "005",2 -> "01" + (begin ; carry overflow + (set! format:fn-len digits) + (format:fn-zfill #t 1) ; add a 1 before fn-str + (string-set! format:fn-str 0 #\1) + (set! format:fn-dot (+ format:fn-dot 1))) + (set! format:fn-len digits))) + (set! c (+ (- (char->integer (string-ref format:fn-str i)) + format:zero-ch) c)) + (string-set! format:fn-str i (integer->char + (if (< c 10) + (+ c format:zero-ch) + (+ (- c 10) format:zero-ch)))) + (set! c (if (< c 10) 0 1)))) + +(define (format:fn-out modifier add-leading-zero?) + (if format:fn-pos? + (if (eq? modifier 'at) + (format:out-char #\+)) + (format:out-char #\-)) + (if (= format:fn-dot 0) + (if add-leading-zero? + (format:out-char #\0)) + (format:out-substr format:fn-str 0 format:fn-dot)) + (format:out-char #\.) + (format:out-substr format:fn-str format:fn-dot format:fn-len)) + +(define (format:en-out edigits expch) + (format:out-char (if expch (integer->char expch) format:expch)) + (format:out-char (if format:en-pos? #\+ #\-)) + (if edigits + (if (< format:en-len edigits) + (format:out-fill (- edigits format:en-len) #\0))) + (format:out-substr format:en-str 0 format:en-len)) + +(define (format:fn-strip) ; strip trailing zeros but one + (string-set! format:fn-str format:fn-len #\0) + (do ((i format:fn-len (- i 1))) + ((or (not (char=? (string-ref format:fn-str i) #\0)) + (<= i format:fn-dot)) + (set! format:fn-len (+ i 1))))) + +(define (format:fn-zlead) ; count leading zeros + (do ((i 0 (+ i 1))) + ((or (= i format:fn-len) + (not (char=? (string-ref format:fn-str i) #\0))) + (if (= i format:fn-len) ; found a real zero + 0 + i)))) + + +;;; some global functions not found in SLIB + +(define (format:string-capitalize-first str) ; "hello" -> "Hello" + (let ((cap-str (string-copy str)) ; "hELLO" -> "Hello" + (non-first-alpha #f) ; "*hello" -> "*Hello" + (str-len (string-length str))) ; "hello you" -> "Hello you" + (do ((i 0 (+ i 1))) + ((= i str-len) cap-str) + (let ((c (string-ref str i))) + (if (char-alphabetic? c) + (if non-first-alpha + (string-set! cap-str i (char-downcase c)) + (begin + (set! non-first-alpha #t) + (string-set! cap-str i (char-upcase c))))))))) + +(define (format:list-head l k) + (if (= k 0) + '() + (cons (car l) (format:list-head (cdr l) (- k 1))))) + + +;; Aborts the program when a formatting error occures. This is a null +;; argument closure to jump to the interpreters toplevel continuation. + +(define format:abort (lambda () (slib:error "error in format"))) + +(define format format:format) + +;; If this is not possible then a continuation is used to recover +;; properly from a format error. In this case format returns #f. + +;(define format:abort +; (lambda () (format:error-continuation #f))) + +;(define format +; (lambda args ; wraps format:format with an error +; (call-with-current-continuation ; continuation +; (lambda (cont) +; (set! format:error-continuation cont) +; (apply format:format args))))) + +;eof |