;;;; the printer
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB-IMPL")
;;;; exported printer control variables
(defvar *print-readably* nil
"If true, all objects will be printed readably. If readable printing
is impossible, an error will be signalled. This overrides the value of
*PRINT-ESCAPE*.")
(defvar *print-escape* t
"Should we print in a reasonably machine-readable way? (possibly
overridden by *PRINT-READABLY*)")
(defvar *print-pretty* nil ; (set later when pretty-printer is initialized)
"Should pretty printing be used?")
(defvar *print-base* 10.
"The output base for RATIONALs (including integers).")
(defvar *print-radix* nil
"Should base be verified when printing RATIONALs?")
(defvar *print-level* nil
"How many levels should be printed before abbreviating with \"#\"?")
(defvar *print-length* nil
"How many elements at any level should be printed before abbreviating
with \"...\"?")
(defvar *print-vector-length* nil
"Like *PRINT-LENGTH* but works on strings and bit-vectors.
Does not affect the cases that are already controlled by *PRINT-LENGTH*")
(defvar *print-circle* nil
"Should we use #n= and #n# notation to preserve uniqueness in general (and
circularity in particular) when printing?")
(defvar *print-case* :upcase
"What case should the printer should use default?")
(defvar *print-array* t
"Should the contents of arrays be printed?")
(defvar *print-gensym* t
"Should #: prefixes be used when printing symbols with null SYMBOL-PACKAGE?")
(defvar *print-lines* nil
"The maximum number of lines to print per object.")
(defvar *print-right-margin* nil
"The position of the right margin in ems (for pretty-printing).")
(defvar *print-miser-width* nil
"If the remaining space between the current column and the right margin
is less than this, then print using ``miser-style'' output. Miser
style conditional newlines are turned on, and all indentations are
turned off. If NIL, never use miser mode.")
(defvar *print-pprint-dispatch*
(sb-pretty::make-pprint-dispatch-table #() nil nil)
"The pprint-dispatch-table that controls how to pretty-print objects.")
(defvar *suppress-print-errors* nil
"Suppress printer errors when the condition is of the type designated by this
variable: an unreadable object representing the error is printed instead.")
;; duplicate defglobal because this file is compiled before "reader"
(define-load-time-global *standard-readtable* nil)
(defun %with-standard-io-syntax (function)
(declare (type function function))
(declare (dynamic-extent function))
(let ((*package* #.(find-package "COMMON-LISP-USER"))
(*print-array* t)
(*print-base* 10)
(*print-case* :upcase)
(*print-circle* nil)
(*print-escape* t)
(*print-gensym* t)
(*print-length* nil)
(*print-level* nil)
(*print-lines* nil)
(*print-miser-width* nil)
(*print-pprint-dispatch* sb-pretty::*standard-pprint-dispatch-table*)
(*print-pretty* nil)
(*print-radix* nil)
(*print-readably* t)
(*print-right-margin* nil)
(*read-base* 10)
(*read-default-float-format* 'single-float)
(*read-eval* t)
(*read-suppress* nil)
(*readtable* *standard-readtable*)
(*suppress-print-errors* nil)
(*print-vector-length* nil))
(funcall function)))
;;;; routines to print objects
(macrolet ((def (fn doc &rest forms)
`(defun ,fn
(object
&key
,@(if (eq fn 'write) '(stream))
((:escape *print-escape*) *print-escape*)
((:radix *print-radix*) *print-radix*)
((:base *print-base*) *print-base*)
((:circle *print-circle*) *print-circle*)
((:pretty *print-pretty*) *print-pretty*)
((:level *print-level*) *print-level*)
((:length *print-length*) *print-length*)
((:case *print-case*) *print-case*)
((:array *print-array*) *print-array*)
((:gensym *print-gensym*) *print-gensym*)
((:readably *print-readably*) *print-readably*)
((:right-margin *print-right-margin*)
*print-right-margin*)
((:miser-width *print-miser-width*)
*print-miser-width*)
((:lines *print-lines*) *print-lines*)
((:pprint-dispatch *print-pprint-dispatch*)
*print-pprint-dispatch*)
((:suppress-errors *suppress-print-errors*)
*suppress-print-errors*))
,doc
(declare (explicit-check))
,@forms)))
(def write
"Output OBJECT to the specified stream, defaulting to *STANDARD-OUTPUT*."
(output-object object (out-stream-from-designator stream))
object)
(def write-to-string
"Return the printed representation of OBJECT as a string."
(stringify-object object)))
;;; Same as a call to (WRITE OBJECT :STREAM STREAM), but returning OBJECT.
(defun %write (object stream)
(declare (explicit-check))
(output-object object (out-stream-from-designator stream))
object)
(defun prin1 (object &optional stream)
"Output a mostly READable printed representation of OBJECT on the specified
STREAM."
(declare (explicit-check))
(let ((*print-escape* t))
(output-object object (out-stream-from-designator stream)))
object)
(defun princ (object &optional stream)
"Output an aesthetic but not necessarily READable printed representation
of OBJECT on the specified STREAM."
(declare (explicit-check))
(let ((*print-escape* nil)
(*print-readably* nil))
(output-object object (out-stream-from-designator stream)))
object)
(defun print (object &optional stream)
"Output a newline, the mostly READable printed representation of OBJECT, and
space to the specified STREAM."
(declare (explicit-check))
(let ((stream (out-stream-from-designator stream)))
(terpri stream)
(prin1 object stream)
(write-char #\space stream)
object))
(defun pprint (object &optional stream)
"Prettily output OBJECT preceded by a newline."
(declare (explicit-check))
(let ((*print-pretty* t)
(*print-escape* t)
(stream (out-stream-from-designator stream)))
(terpri stream)
(output-object object stream))
(values))
(defun prin1-to-string (object)
"Return the printed representation of OBJECT as a string with
slashification on."
(let ((*print-escape* t))
(stringify-object object)))
(defun princ-to-string (object)
"Return the printed representation of OBJECT as a string with
slashification off."
(let ((*print-escape* nil)
(*print-readably* nil))
(stringify-object object)))
;;; This produces the printed representation of an object as a string.
;;; The few ...-TO-STRING functions above call this.
(defun stringify-object (object)
(typecase object
(integer
(multiple-value-bind (fun pretty)
(and *print-pretty* (pprint-dispatch object))
(if pretty
(%with-output-to-string (stream)
(sb-pretty::with-pretty-stream (stream)
(funcall fun stream object)))
(let ((buffer-size (approx-chars-in-repr object)))
(let* ((string (make-string buffer-size :element-type 'base-char))
(stream (%make-finite-base-string-output-stream string)))
(declare (inline %make-finite-base-string-output-stream))
(declare (truly-dynamic-extent stream))
(output-integer object stream *print-base* *print-radix*)
(%shrink-vector string
(finite-base-string-output-stream-pointer stream)))))))
;; Could do something for other numeric types, symbols, ...
(t
(%with-output-to-string (stream)
(output-object object stream)))))
;;; Estimate the number of chars in the printed representation of OBJECT.
;;; The answer must be an overestimate or exact; never an underestimate.
(defun approx-chars-in-repr (object)
(declare (integer object))
;; Round *PRINT-BASE* down to the nearest lower power-of-2, call that N,
;; and "guess" that the one character can represent N bits.
;; This is exact for bases which are exactly a power-of-2, or an overestimate
;; otherwise, as mandated by the finite output stream.
(let ((bits-per-char
(aref #.(coerce
;; base 2 or base 3 = 1 bit per character
;; base 4 .. base 7 = 2 bits per character
;; base 8 .. base 15 = 3 bits per character, etc
#(1 1 2 2 2 2 3 3 3 3 3 3 3 3
4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5)
'(vector (unsigned-byte 8)))
(- *print-base* 2))))
(+ (if (minusp object) 1 0) ; leading sign
(if *print-radix* 4 0) ; #rNN or trailing decimal
(ceiling (if (fixnump object)
sb-vm:n-positive-fixnum-bits
(* (%bignum-length object) sb-bignum::digit-size))
bits-per-char))))
;;;; support for the PRINT-UNREADABLE-OBJECT macro
(defun print-not-readable-error (object stream)
(restart-case
(error 'print-not-readable :object object)
(print-unreadably ()
:report "Print unreadably."
(let ((*print-readably* nil))
(output-object object stream)
object))
(use-value (o)
:report "Supply an object to be printed instead."
:interactive
(lambda ()
(read-evaluated-form "~@<Enter an object (evaluated): ~@:>"))
(output-object o stream)
o)))
;;; guts of PRINT-UNREADABLE-OBJECT
(defun %print-unreadable-object (object stream flags &optional body)
(declare (type (or null function) body))
(if *print-readably*
(print-not-readable-error object stream)
(flet ((print-description (&aux (type (logbitp 0 (truly-the (mod 4) flags)))
(identity (logbitp 1 flags)))
(when type
(write (type-of object) :stream stream :circle nil
:level nil :length nil)
;; Do NOT insert a pprint-newline here.
;; See ba34717602d80e5fd74d10e61f4729fb0d019a0c
(write-char #\space stream))
(when body
(funcall body))
(when identity
(when (or body (not type))
(write-char #\space stream))
;; Nor here.
(write-char #\{ stream)
(%output-integer-in-base (get-lisp-obj-address object) 16 stream)
(write-char #\} stream))))
(cond ((print-pretty-on-stream-p stream)
;; Since we're printing prettily on STREAM, format the
;; object within a logical block. PPRINT-LOGICAL-BLOCK does
;; not rebind the stream when it is already a pretty stream,
;; so output from the body will go to the same stream.
(pprint-logical-block (stream nil :prefix "#<" :suffix ">")
(print-description)))
(t
(write-string "#<" stream)
(print-description)
(write-char #\> stream)))))
nil)
;;;; OUTPUT-OBJECT -- the main entry point
;;; Objects whose print representation identifies them EQLly don't
;;; need to be checked for circularity.
(defun uniquely-identified-by-print-p (x)
(or (numberp x)
(characterp x)
(and (symbolp x)
(sb-xc:symbol-package x))))
(defvar *in-print-error* nil)
;;; Output OBJECT to STREAM observing all printer control variables.
(defun output-object (object stream)
;; FIXME: this function is declared EXPLICIT-CHECK, so it allows STREAM
;; to be T or NIL (a stream-designator), which is not really right
;; if eventually the call will be to a PRINT-OBJECT method,
;; since the generic function should always receive a stream.
(declare (explicit-check))
(labels ((print-it (stream)
(multiple-value-bind (fun pretty)
(and *print-pretty* (pprint-dispatch object))
(if pretty
(sb-pretty::with-pretty-stream (stream)
(funcall fun stream object))
(output-ugly-object stream object))))
(handle-it (stream)
(if *suppress-print-errors*
(handler-bind
((condition
(lambda (condition)
(when (typep condition *suppress-print-errors*)
(cond (*in-print-error*
(write-string "(error printing " stream)
(write-string *in-print-error* stream)
(write-string ")" stream))
(t
(let ((*print-readably* nil)
(*print-escape* t))
(write-string
"#<error printing a " stream)
(let ((*in-print-error* "type"))
(output-object (type-of object) stream))
(write-string ": " stream)
(let ((*in-print-error* "condition"))
(output-object condition stream))
(write-string ">" stream))))
(return-from handle-it object)))))
(print-it stream))
(print-it stream)))
(check-it (stream)
(multiple-value-bind (marker initiate)
(check-for-circularity object t)
(if (eq initiate :initiate)
(let ((*circularity-hash-table*
(make-hash-table :test 'eq)))
(check-it *null-broadcast-stream*)
(let ((*circularity-counter* 0))
(check-it stream)))
;; otherwise
(if marker
(when (handle-circularity marker stream)
(handle-it stream))
(handle-it stream))))))
(cond (;; Maybe we don't need to bother with circularity detection.
(or (not *print-circle*)
(uniquely-identified-by-print-p object))
(handle-it stream))
(;; If we have already started circularity detection, this
;; object might be a shared reference. If we have not, then
;; if it is a compound object it might contain a circular
;; reference to itself or multiple shared references.
(or *circularity-hash-table*
(compound-object-p object))
(check-it stream))
(t
(handle-it stream)))))
;;; Output OBJECT to STREAM observing all printer control variables
;;; except for *PRINT-PRETTY*. Note: if *PRINT-PRETTY* is non-NIL,
;;; then the pretty printer will be used for any components of OBJECT,
;;; just not for OBJECT itself.
(defun output-ugly-object (stream object)
(when (%instancep object)
(let ((layout (%instance-layout object)))
;; If an instance has no layout, do something sensible. Can't compare layout
;; to 0 using EQ or EQL because that would be tautologically NIL as per fndb.
;; This is better than declaring EQ or %INSTANCE-LAYOUT notinline.
(unless (logtest (get-lisp-obj-address layout) sb-vm:widetag-mask)
(return-from output-ugly-object
(print-unreadable-object (object stream :identity t)
(prin1 'instance stream))))
(let* ((wrapper (layout-friend layout))
(classoid (wrapper-classoid wrapper)))
;; Additionally, don't crash if the object is an obsolete thing with
;; no update protocol.
(when (or (sb-kernel::undefined-classoid-p classoid)
(and (wrapper-invalid wrapper)
(logtest (layout-flags layout)
(logior +structure-layout-flag+
+condition-layout-flag+))))
(return-from output-ugly-object
(print-unreadable-object (object stream :identity t)
(format stream "UNPRINTABLE instance of ~W" classoid)))))))
(when (funcallable-instance-p object)
(let ((layout (%fun-layout object)))
(unless (logtest (get-lisp-obj-address layout) sb-vm:widetag-mask)
(return-from output-ugly-object
(print-unreadable-object (object stream :identity t)
(prin1 'funcallable-instance stream))))))
(print-object object stream))
;;;; symbols
(defmethod print-object ((object symbol) stream)
(if (or *print-escape* *print-readably*)
;; Write so that reading back works
(output-symbol object (sb-xc:symbol-package object) stream)
;; Write only the characters of the name, never the package
(let ((rt *readtable*))
(funcall (truly-the function
(choose-symbol-out-fun *print-case* (%readtable-case rt)))
(symbol-name object) stream rt))))
(defun output-symbol (symbol package stream)
(let* ((readably *print-readably*)
(readtable (if readably *standard-readtable* *readtable*))
(out-fun (choose-symbol-out-fun *print-case* (%readtable-case readtable))))
(flet ((output-token (name)
(declare (type simple-string name))
(cond ((or (and (readtable-normalization readtable)
(not (sb-unicode:normalized-p name :nfkc)))
(symbol-quotep name readtable))
;; Output NAME surrounded with |'s,
;; and with any embedded |'s or \'s escaped.
(write-char #\| stream)
(dotimes (index (length name))
(let ((char (char name index)))
;; Hmm. Should these depend on what characters
;; are actually escapes in the readtable ?
;; (See similar remark at DEFUN QUOTE-STRING)
(when (or (char= char #\\) (char= char #\|))
(write-char #\\ stream))
(write-char char stream)))
(write-char #\| stream))
(t
(funcall (truly-the function out-fun) name stream readtable)))))
(let ((name (symbol-name symbol))
(current (sane-package)))
(cond
;; The ANSI spec "22.1.3.3.1 Package Prefixes for Symbols"
;; requires that keywords be printed with preceding colons
;; always, regardless of the value of *PACKAGE*.
((eq package *keyword-package*)
(write-char #\: stream))
;; Otherwise, if the symbol's home package is the current
;; one, then a prefix is never necessary.
((eq package current))
;; Uninterned symbols print with a leading #:.
((null package)
(when (or *print-gensym* readably)
(write-string "#:" stream)))
(t
(multiple-value-bind (found accessible) (find-symbol name current)
;; If we can find the symbol by looking it up, it need not
;; be qualified. This can happen if the symbol has been
;; inherited from a package other than its home package.
;;
;; To preserve print-read consistency, use the local nickname if
;; one exists.
(unless (and accessible (eq found symbol))
(output-token (or (package-local-nickname package current)
(package-name package)))
(write-string (if (eql (find-external-symbol name package) 0) "::" ":")
stream)))))
(output-token name)))))
;;;; escaping symbols
;;; When we print symbols we have to figure out if they need to be
;;; printed with escape characters. This isn't a whole lot easier than
;;; reading symbols in the first place.
;;;
;;; For each character, the value of the corresponding element is a
;;; fixnum with bits set corresponding to attributes that the
;;; character has. All characters have at least one bit set, so we can
;;; search for any character with a positive test.
;;; constants which are a bit-mask for each interesting character attribute
(defconstant other-attribute (ash 1 0)) ; Anything else legal.
(defconstant number-attribute (ash 1 1)) ; A numeric digit.
(defconstant uppercase-attribute (ash 1 2)) ; An uppercase letter.
(defconstant lowercase-attribute (ash 1 3)) ; A lowercase letter.
(defconstant sign-attribute (ash 1 4)) ; +-
(defconstant extension-attribute (ash 1 5)) ; ^_
(defconstant dot-attribute (ash 1 6)) ; .
(defconstant slash-attribute (ash 1 7)) ; /
(defconstant funny-attribute (ash 1 8)) ; Anything illegal.
;;; LETTER-ATTRIBUTE is a local of SYMBOL-QUOTEP. It matches letters
;;; that don't need to be escaped (according to READTABLE-CASE.)
(defconstant-eqx +attribute-names+
'((number . number-attribute) (lowercase . lowercase-attribute)
(uppercase . uppercase-attribute) (letter . letter-attribute)
(sign . sign-attribute) (extension . extension-attribute)
(dot . dot-attribute) (slash . slash-attribute)
(other . other-attribute) (funny . funny-attribute))
#'equal)
;;; For each character, the value of the corresponding element is the
;;; lowest base in which that character is a digit.
(defconstant-eqx +digit-bases+
#.(let ((a (sb-xc:make-array 128 ; FIXME
:retain-specialization-for-after-xc-core t
:element-type '(unsigned-byte 8)
:initial-element 36)))
(dotimes (i 36 a)
(let ((char (digit-char i 36)))
(setf (aref a (char-code char)) i))))
#'equalp)
(defconstant-eqx +character-attributes+
#.(let ((a (sb-xc:make-array 160 ; FIXME
:retain-specialization-for-after-xc-core t
:element-type '(unsigned-byte 16)
:initial-element 0)))
(flet ((set-bit (char bit)
(let ((code (char-code char)))
(setf (aref a code) (logior bit (aref a code))))))
(dolist (char '(#\! #\@ #\$ #\% #\& #\* #\= #\~ #\[ #\] #\{ #\}
#\? #\< #\>))
(set-bit char other-attribute))
(dotimes (i 10)
(set-bit (digit-char i) number-attribute))
(do ((code (char-code #\A) (1+ code))
(end (char-code #\Z)))
((> code end))
(declare (fixnum code end))
(set-bit (code-char code) uppercase-attribute)
(set-bit (char-downcase (code-char code)) lowercase-attribute))
(set-bit #\- sign-attribute)
(set-bit #\+ sign-attribute)
(set-bit #\^ extension-attribute)
(set-bit #\_ extension-attribute)
(set-bit #\. dot-attribute)
(set-bit #\/ slash-attribute)
;; Mark anything not explicitly allowed as funny.
(dotimes (i 160) ; FIXME
(when (zerop (aref a i))
(setf (aref a i) funny-attribute))))
a)
#'equalp)
;;; A FSM-like thingie that determines whether a symbol is a potential
;;; number or has evil characters in it.
(defun symbol-quotep (name readtable)
(declare (simple-string name))
(macrolet ((advance (tag &optional (at-end t))
`(progn
(when (= index len)
,(if at-end '(go TEST-SIGN) '(return nil)))
(setq current (schar name index)
code (char-code current)
bits (cond ; FIXME
((< code 160) (aref attributes code))
((upper-case-p current) uppercase-attribute)
((lower-case-p current) lowercase-attribute)
(t other-attribute)))
(incf index)
(go ,tag)))
(test (&rest attributes)
`(not (zerop
(the fixnum
(logand
(logior ,@(mapcar
(lambda (x)
(or (cdr (assoc x
+attribute-names+))
(error "Blast!")))
attributes))
bits)))))
(digitp ()
`(and (< code 128) ; FIXME
(< (the fixnum (aref bases code)) base))))
(prog ((len (length name))
(attributes +character-attributes+)
(bases +digit-bases+)
(base *print-base*)
(letter-attribute
(case (%readtable-case readtable)
(#.+readtable-upcase+ uppercase-attribute)
(#.+readtable-downcase+ lowercase-attribute)
(t (logior lowercase-attribute uppercase-attribute))))
(index 0)
(bits 0)
(code 0)
current)
(declare (fixnum len base index bits code))
(advance START t)
TEST-SIGN ; At end, see whether it is a sign...
(return (not (test sign)))
OTHER ; not potential number, see whether funny chars...
(let ((mask (logxor (logior lowercase-attribute uppercase-attribute
funny-attribute)
letter-attribute)))
(do ((i (1- index) (1+ i)))
((= i len) (return-from symbol-quotep nil))
(unless (zerop (logand (let* ((char (schar name i))
(code (char-code char)))
(cond
((< code 160) (aref attributes code))
((upper-case-p char) uppercase-attribute)
((lower-case-p char) lowercase-attribute)
(t other-attribute)))
mask))
(return-from symbol-quotep t))))
START
(when (digitp)
(if (test letter)
(advance LAST-DIGIT-ALPHA)
(advance DIGIT)))
(when (test letter number other slash) (advance OTHER nil))
(when (char= current #\.) (advance DOT-FOUND))
(when (test sign extension) (advance START-STUFF nil))
(return t)
DOT-FOUND ; leading dots...
(when (test letter) (advance START-DOT-MARKER nil))
(when (digitp) (advance DOT-DIGIT))
(when (test number other) (advance OTHER nil))
(when (test extension slash sign) (advance START-DOT-STUFF nil))
(when (char= current #\.) (advance DOT-FOUND))
(return t)
START-STUFF ; leading stuff before any dot or digit
(when (digitp)
(if (test letter)
(advance LAST-DIGIT-ALPHA)
(advance DIGIT)))
(when (test number other) (advance OTHER nil))
(when (test letter) (advance START-MARKER nil))
(when (char= current #\.) (advance START-DOT-STUFF nil))
(when (test sign extension slash) (advance START-STUFF nil))
(return t)
START-MARKER ; number marker in leading stuff...
(when (test letter) (advance OTHER nil))
(go START-STUFF)
START-DOT-STUFF ; leading stuff containing dot without digit...
(when (test letter) (advance START-DOT-STUFF nil))
(when (digitp) (advance DOT-DIGIT))
(when (test sign extension dot slash) (advance START-DOT-STUFF nil))
(when (test number other) (advance OTHER nil))
(return t)
START-DOT-MARKER ; number marker in leading stuff with dot..
;; leading stuff containing dot without digit followed by letter...
(when (test letter) (advance OTHER nil))
(go START-DOT-STUFF)
DOT-DIGIT ; in a thing with dots...
(when (test letter) (advance DOT-MARKER))
(when (digitp) (advance DOT-DIGIT))
(when (test number other) (advance OTHER nil))
(when (test sign extension dot slash) (advance DOT-DIGIT))
(return t)
DOT-MARKER ; number marker in number with dot...
(when (test letter) (advance OTHER nil))
(go DOT-DIGIT)
LAST-DIGIT-ALPHA ; previous char is a letter digit...
(when (or (digitp) (test sign slash))
(advance ALPHA-DIGIT))
(when (test letter number other dot) (advance OTHER nil))
(return t)
ALPHA-DIGIT ; seen a digit which is a letter...
(when (or (digitp) (test sign slash))
(if (test letter)
(advance LAST-DIGIT-ALPHA)
(advance ALPHA-DIGIT)))
(when (test letter) (advance ALPHA-MARKER))
(when (test number other dot) (advance OTHER nil))
(return t)
ALPHA-MARKER ; number marker in number with alpha digit...
(when (test letter) (advance OTHER nil))
(go ALPHA-DIGIT)
DIGIT ; seen only ordinary (non-alphabetic) numeric digits...
(when (digitp)
(if (test letter)
(advance ALPHA-DIGIT)
(advance DIGIT)))
(when (test number other) (advance OTHER nil))
(when (test letter) (advance MARKER))
(when (test extension slash sign) (advance DIGIT))
(when (char= current #\.) (advance DOT-DIGIT))
(return t)
MARKER ; number marker in a numeric number...
;; ("What," you may ask, "is a 'number marker'?" It's something
;; that a conforming implementation might use in number syntax.
;; See ANSI 2.3.1.1 "Potential Numbers as Tokens".)
(when (test letter) (advance OTHER nil))
(go DIGIT))))
;;;; case hackery: One of these functions is chosen to output symbol
;;;; names according to the values of *PRINT-CASE* and READTABLE-CASE.
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :UPCASE :UPCASE
;;; :DOWNCASE :DOWNCASE
;;; :PRESERVE any
(defun output-preserve-symbol (pname stream readtable)
(declare (ignore readtable))
(write-string pname stream))
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :UPCASE :DOWNCASE
(defun output-lowercase-symbol (pname stream readtable)
(declare (simple-string pname) (ignore readtable))
(dotimes (index (length pname))
(let ((char (schar pname index)))
(write-char (char-downcase char) stream))))
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :DOWNCASE :UPCASE
(defun output-uppercase-symbol (pname stream readtable)
(declare (simple-string pname) (ignore readtable))
(dotimes (index (length pname))
(let ((char (schar pname index)))
(write-char (char-upcase char) stream))))
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :UPCASE :CAPITALIZE
;;; :DOWNCASE :CAPITALIZE
(defun output-capitalize-symbol (pname stream readtable)
(declare (simple-string pname))
(let ((prev-not-alphanum t)
(up (eql (%readtable-case readtable) +readtable-upcase+)))
(dotimes (i (length pname))
(let ((char (char pname i)))
(write-char (if up
(if (or prev-not-alphanum (lower-case-p char))
char
(char-downcase char))
(if prev-not-alphanum
(char-upcase char)
char))
stream)
(setq prev-not-alphanum (not (alphanumericp char)))))))
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :INVERT any
(defun output-invert-symbol (pname stream readtable)
(declare (simple-string pname) (ignore readtable))
(let ((all-upper t)
(all-lower t))
(dotimes (i (length pname))
(let ((ch (schar pname i)))
(when (both-case-p ch)
(if (upper-case-p ch)
(setq all-lower nil)
(setq all-upper nil)))))
(cond (all-upper (output-lowercase-symbol pname stream nil))
(all-lower (output-uppercase-symbol pname stream nil))
(t
(write-string pname stream)))))
(defun choose-symbol-out-fun (print-case readtable-case)
(macrolet
((compute-fun-vector (&aux (vector (make-array 12)))
;; Pack a 2D array of functions into a simple-vector.
;; Major axis is *PRINT-CASE*, minor axis is %READTABLE-CASE.
(dotimes (readtable-case-index 4)
(dotimes (print-case-index 3)
(let ((readtable-case
(elt '(:upcase :downcase :preserve :invert) readtable-case-index))
(print-case
(elt '(:upcase :downcase :capitalize) print-case-index)))
(setf (aref vector (logior (ash print-case-index 2)
readtable-case-index))
(case readtable-case
(:upcase
(case print-case
(:upcase 'output-preserve-symbol)
(:downcase 'output-lowercase-symbol)
(:capitalize 'output-capitalize-symbol)))
(:downcase
(case print-case
(:upcase 'output-uppercase-symbol)
(:downcase 'output-preserve-symbol)
(:capitalize 'output-capitalize-symbol)))
(:preserve 'output-preserve-symbol)
(:invert 'output-invert-symbol))))))
`(load-time-value (vector ,@(map 'list (lambda (x) `(function ,x)) vector))
t)))
(aref (compute-fun-vector)
(logior (case print-case (:upcase 0) (:downcase 4) (t 8))
(truly-the (mod 4) readtable-case)))))
;;;; recursive objects
(defmethod print-object ((list cons) stream)
(descend-into (stream)
(write-char #\( stream)
(let ((length 0)
(list list))
(loop
(punt-print-if-too-long length stream)
(output-object (pop list) stream)
(unless list
(return))
(when (or (atom list)
(check-for-circularity list))
(write-string " . " stream)
(output-object list stream)
(return))
(write-char #\space stream)
(incf length)))
(write-char #\) stream)))
(defmethod print-object ((vector vector) stream)
(let ((readably *print-readably*))
(flet ((cut-length ()
(when (and (not readably)
*print-vector-length*
(> (length vector) *print-vector-length*))
(print-unreadable-object (vector stream :type t :identity t)
(format stream "~A..."
(make-array *print-vector-length*
:element-type (array-element-type vector)
:displaced-to vector)))
t)))
(cond ((stringp vector)
(cond ((and readably (not (typep vector '(vector character))))
(output-unreadable-array-readably vector stream))
((and *print-escape*
(cut-length)))
((or *print-escape* readably)
(write-char #\" stream)
(quote-string vector stream)
(write-char #\" stream))
(t
(write-string vector stream))))
((or (null (array-element-type vector))
(not (or *print-array* readably)))
(output-terse-array vector stream))
((bit-vector-p vector)
(cond ((cut-length))
(t
(write-string "#*" stream)
(dovector (bit vector)
;; (Don't use OUTPUT-OBJECT here, since this code
;; has to work for all possible *PRINT-BASE* values.)
(write-char (if (zerop bit) #\0 #\1) stream)))))
((or (not readably) (array-readably-printable-p vector))
(descend-into (stream)
(write-string "#(" stream)
(dotimes (i (length vector))
(unless (zerop i)
(write-char #\space stream))
(punt-print-if-too-long i stream)
(output-object (aref vector i) stream))
(write-string ")" stream)))
(t
(output-unreadable-array-readably vector stream))))))
;;; This function outputs a string quoting characters sufficiently
;;; so that someone can read it in again. Basically, put a slash in
;;; front of an character satisfying NEEDS-SLASH-P.
(defun quote-string (string stream)
(macrolet ((needs-slash-p (char)
;; KLUDGE: We probably should look at the readtable, but just do
;; this for now. [noted by anonymous long ago] -- WHN 19991130
`(or (char= ,char #\\)
(char= ,char #\"))))
(with-array-data ((data string) (start) (end)
:check-fill-pointer t)
(do ((index start (1+ index)))
((>= index end))
(let ((char (schar data index)))
(when (needs-slash-p char) (write-char #\\ stream))
(write-char char stream))))))
(defun array-readably-printable-p (array)
(and (eq (array-element-type array) t)
(let ((zero (position 0 (array-dimensions array)))
(number (position 0 (array-dimensions array)
:test (complement #'eql)
:from-end t)))
(or (null zero) (null number) (> zero number)))))
;;; Output the printed representation of any array in either the #< or #A
;;; form.
(defmethod print-object ((array array) stream)
(if (and (or *print-array* *print-readably*) (array-element-type array))
(output-array-guts array stream)
(output-terse-array array stream)))
;;; Output the abbreviated #< form of an array.
(defun output-terse-array (array stream)
(let ((*print-level* nil)
(*print-length* nil))
(if (and (not (array-element-type array)) *print-readably* *read-eval*)
(format stream "#.(~S '~D :ELEMENT-TYPE ~S)"
'make-array (array-dimensions array) nil)
(print-unreadable-object (array stream :type t :identity t)))))
;;; Convert an array into a list that can be used with MAKE-ARRAY's
;;; :INITIAL-CONTENTS keyword argument.
(defun listify-array (array)
(flet ((compact (seq)
(typecase array
(string
(coerce seq '(simple-array character (*))))
((array bit)
(coerce seq 'bit-vector))
(t
seq))))
(if (typep array '(or string bit-vector))
(compact array)
(with-array-data ((data array) (start) (end))
(declare (ignore end))
(labels ((listify (dimensions index)
(if (null dimensions)
(aref data index)
(let* ((dimension (car dimensions))
(dimensions (cdr dimensions))
(count (reduce #'* dimensions)))
(loop for i below dimension
for list = (listify dimensions index)
collect (if (and dimensions
(null (cdr dimensions)))
(compact list)
list)
do (incf index count))))))
(listify (array-dimensions array) start))))))
;;; Use nonstandard #A(dimensions element-type contents)
;;; to avoid using #.
(defun output-unreadable-array-readably (array stream)
(let ((array (list* (array-dimensions array)
(array-element-type array)
(listify-array array))))
(write-string "#A" stream)
(write array :stream stream)
nil))
;;; Output the readable #A form of an array.
(defun output-array-guts (array stream)
(cond ((or (not *print-readably*)
(array-readably-printable-p array))
(write-char #\# stream)
(output-integer (array-rank array) stream 10 nil)
(write-char #\A stream)
(with-array-data ((data array) (start) (end))
(declare (ignore end))
(sub-output-array-guts data (array-dimensions array) stream start)))
(t
(output-unreadable-array-readably array stream))))
(defun sub-output-array-guts (array dimensions stream index)
(declare (type (simple-array * (*)) array) (fixnum index))
(cond ((null dimensions)
(output-object (aref array index) stream))
(t
(descend-into (stream)
(write-char #\( stream)
(let* ((dimension (car dimensions))
(dimensions (cdr dimensions))
(count (reduce #'* dimensions)))
(dotimes (i dimension)
(unless (zerop i)
(write-char #\space stream))
(punt-print-if-too-long i stream)
(sub-output-array-guts array dimensions stream index)
(incf index count)))
(write-char #\) stream)))))
;;;; integer, ratio, and complex printing (i.e. everything but floats)
(defun %output-radix (base stream)
(write-char #\# stream)
(write-char (case base
(2 #\b)
(8 #\o)
(16 #\x)
(t (%output-integer-in-base base 10 stream) #\r))
stream))
;;; *POWER-CACHE* is an alist mapping bases to power-vectors. It is
;;; filled and probed by POWERS-FOR-BASE. SCRUB-POWER-CACHE is called
;;; always prior a GC to drop overly large bignums from the cache.
;;;
;;; It doesn't need a lock, but if you work on SCRUB-POWER-CACHE or
;;; POWERS-FOR-BASE, see that you don't break the assumptions!
(define-load-time-global *power-cache* (make-array 37 :initial-element nil))
(declaim (type (simple-vector 37) *power-cache*))
(defconstant +power-cache-integer-length-limit+ 2048)
(defun scrub-power-cache (&aux (cache *power-cache*))
(dotimes (i (length cache))
(let ((powers (aref cache i)))
(when powers
(let ((too-big (position-if
(lambda (x)
(>= (integer-length x)
+power-cache-integer-length-limit+))
(the simple-vector powers))))
(when too-big
(setf (aref cache i) (subseq powers 0 too-big))))))))
;;; Compute (and cache) a power vector for a BASE and LIMIT:
;;; the vector holds integers for which
;;; (aref powers k) == (expt base (expt 2 k))
;;; holds.
(defun powers-for-base (base limit)
(flet ((compute-powers (from)
(let (powers)
(do ((p from (* p p)))
((> p limit)
;; We don't actually need this, but we also
;; prefer not to cons it up a second time...
(push p powers))
(push p powers))
(nreverse powers))))
(let* ((cache *power-cache*)
(powers (aref cache base)))
(setf (aref cache base)
(concatenate 'vector powers
(compute-powers
(if powers
(let* ((len (length powers))
(max (svref powers (1- len))))
(if (> max limit)
(return-from powers-for-base powers)
(* max max)))
base)))))))
;; Algorithm by Harald Hanche-Olsen, sbcl-devel 2005-02-05
(defun %output-huge-integer-in-base (n base stream)
(declare (type bignum n) (type fixnum base))
;; POWER is a vector for which the following holds:
;; (aref power k) == (expt base (expt 2 k))
(let* ((power (powers-for-base base n))
(k-start (or (position-if (lambda (x) (> x n)) power)
(bug "power-vector too short"))))
(labels ((bisect (n k exactp)
(declare (fixnum k))
;; N is the number to bisect
;; K on initial entry BASE^(2^K) > N
;; EXACTP is true if 2^K is the exact number of digits
(cond ((zerop n)
(when exactp
(loop repeat (ash 1 k) do (write-char #\0 stream))))
((zerop k)
(write-char
(schar "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" n)
stream))
(t
(setf k (1- k))
(multiple-value-bind (q r) (truncate n (aref power k))
;; EXACTP is NIL only at the head of the
;; initial number, as we don't know the number
;; of digits there, but we do know that it
;; doesn't get any leading zeros.
(bisect q k exactp)
(bisect r k (or exactp (plusp q))))))))
(bisect n k-start nil))))
;;; Not all architectures can stack-allocate lisp strings,
;;; but we can fake it using aliens.
;;; %output-integer-in-base always needs 8 lispwords:
;;; if n-word-bytes = 4 then 8 * 4 = 32 characters
;;; if n-word-bytes = 8 then 8 * 8 = 64 characters
;;; This allows for output in base 2 worst case.
;;; We don't need a trailing null.
(defmacro with-lisp-string-on-alien-stack ((string size-in-chars) &body body)
(let ((size-in-lispwords ; +2 words for lisp string header
(+ 2 (align-up (ceiling (symbol-value size-in-chars) sb-vm:n-word-bytes)
2)))
(alien '#:a)
(sap '#:sap))
;; +1 is for alignment if needed
`(with-alien ((,alien (array unsigned ,(1+ size-in-lispwords))))
(let ((,sap (alien-sap ,alien)))
(when (logtest (sap-int ,sap) sb-vm:lowtag-mask)
(setq ,sap (sap+ ,sap sb-vm:n-word-bytes)))
(setf (sap-ref-word ,sap 0) sb-vm:simple-base-string-widetag
(sap-ref-word ,sap sb-vm:n-word-bytes) (ash sb-vm:n-word-bits
sb-vm:n-fixnum-tag-bits))
(let ((,string
(truly-the simple-base-string
(%make-lisp-obj (logior (sap-int ,sap)
sb-vm:other-pointer-lowtag)))))
,@body)))))
;;; Using specialized routines for the various cases seems to work nicely.
;;;
;;; Testing with 100,000 random integers, output to a sink stream, x86-64:
;;; word-sized integers, base >= 10
;;; old=.062 sec, 4MiB consed; new=.031 sec, 0 bytes consed
;;; word-sized integers, base < 10
;;; old=.104 sec, 4MiB consed; new=.075 sec, 0 bytes consed
;;; bignums in base 16:
;;; old=.125 sec, 20 MiB consed; new=.08 sec, 0 bytes consed
;;;
;;; Not sure why this didn't reduce consing on ppc64 when I tried it.
(defun %output-integer-in-base (integer base stream)
(declare (type (integer 2 36) base))
(when (minusp integer)
(write-char #\- stream)
(setf integer (- integer)))
;; Grrr - a LET binding here causes a constant-folding problem
;; "The function SB-KERNEL:SIMPLE-CHARACTER-STRING-P is undefined."
;; but a symbol-macrolet is ok. This is a FIXME except I don't care.
(symbol-macrolet ((chars "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"))
(declare (optimize (sb-c:insert-array-bounds-checks 0) speed))
(macrolet ((iterative-algorithm ()
`(loop (multiple-value-bind (q r)
(truncate (truly-the word integer) base)
(decf ptr)
(setf (aref buffer ptr) (schar chars r))
(when (zerop (setq integer q)) (return)))))
(recursive-algorithm (dividend-type)
`(named-let recurse ((n integer))
(multiple-value-bind (q r) (truncate (truly-the ,dividend-type n) base)
;; Recurse until you have all the digits pushed on
;; the stack.
(unless (zerop q) (recurse q))
;; Then as each recursive call unwinds, turn the
;; digit (in remainder) into a character and output
;; the character.
(write-char (schar chars r) stream)))))
(cond ((typep integer 'word) ; Division vops can handle this all inline.
#+(and gencgc c-stack-is-control-stack) ; strings can be DX
;; For bases exceeding 10 we know how many characters (at most)
;; will be output. This allows for a single %WRITE-STRING call.
;; There's diminishing payback for other bases because the fixed array
;; size increases, and we don't have a way to elide initial 0-fill.
;; Calling APPROX-CHARS-IN-REPL doesn't help much - we still 0-fill.
(if (< base 10)
(recursive-algorithm word)
(let* ((ptr #.(length (write-to-string sb-ext:most-positive-word
:base 10)))
(buffer (make-array ptr :element-type 'base-char)))
(declare (truly-dynamic-extent buffer))
(iterative-algorithm)
(%write-string buffer stream ptr (length buffer))))
#-(and gencgc c-stack-is-control-stack) ; strings can not be DX
;; Use the alien stack, which is not as fast as using the control stack
;; (when we can). Even the absence of 0-fill doesn't make up for it.
;; Since we've no choice in the matter, might as well allow
;; any value of BASE - it's just a few more words of storage.
(let ((ptr sb-vm:n-word-bits))
(with-lisp-string-on-alien-stack (buffer sb-vm:n-word-bits)
(iterative-algorithm)
(%write-string buffer stream ptr sb-vm:n-word-bits))))
((eql base 16)
;; No division is involved at all.
;; could also specialize for bases 32, 8, 4, and 2 if desired
(loop for pos from (* 4 (1- (ceiling (integer-length integer) 4)))
downto 0 by 4
do (write-char (schar chars (sb-bignum::ldb-bignum=>fixnum 4 pos
integer))
stream)))
;; The ideal cutoff point between this and the "huge" algorithm
;; might be platform-specific, and it also could depend on the output base.
;; Nobody has cared to tweak it in so many years that I think we can
;; arbitrarily say 3 bigdigits is fine.
((<= (sb-bignum:%bignum-length (truly-the bignum integer)) 3)
(recursive-algorithm integer))
(t
(%output-huge-integer-in-base integer base stream)))))
nil)
;;; This gets both a method and a specifically named function
;;; since the latter is called from a few places.
(defmethod print-object ((object integer) stream)
(output-integer object stream *print-base* *print-radix*))
(defun output-integer (integer stream base radixp)
(cond (radixp
(unless (= base 10) (%output-radix base stream))
(%output-integer-in-base integer base stream)
(when (= base 10) (write-char #\. stream)))
(t
(%output-integer-in-base integer base stream))))
(defmethod print-object ((ratio ratio) stream)
(let ((base *print-base*))
(when *print-radix*
(%output-radix base stream))
(%output-integer-in-base (numerator ratio) base stream)
(write-char #\/ stream)
(%output-integer-in-base (denominator ratio) base stream)))
(defmethod print-object ((complex complex) stream)
(write-string "#C(" stream)
(output-object (realpart complex) stream)
(write-char #\space stream)
(output-object (imagpart complex) stream)
(write-char #\) stream))
;;;; float printing
;;; FLONUM-TO-STRING (and its subsidiary function FLOAT-STRING) does
;;; most of the work for all printing of floating point numbers in
;;; FORMAT. It converts a floating point number to a string in a free
;;; or fixed format with no exponent. The interpretation of the
;;; arguments is as follows:
;;;
;;; X - The floating point number to convert, which must not be
;;; negative.
;;; WIDTH - The preferred field width, used to determine the number
;;; of fraction digits to produce if the FDIGITS parameter
;;; is unspecified or NIL. If the non-fraction digits and the
;;; decimal point alone exceed this width, no fraction digits
;;; will be produced unless a non-NIL value of FDIGITS has been
;;; specified. Field overflow is not considerd an error at this
;;; level.
;;; FDIGITS - The number of fractional digits to produce. Insignificant
;;; trailing zeroes may be introduced as needed. May be
;;; unspecified or NIL, in which case as many digits as possible
;;; are generated, subject to the constraint that there are no
;;; trailing zeroes.
;;; SCALE - If this parameter is specified or non-NIL, then the number
;;; printed is (* x (expt 10 scale)). This scaling is exact,
;;; and cannot lose precision.
;;; FMIN - This parameter, if specified or non-NIL, is the minimum
;;; number of fraction digits which will be produced, regardless
;;; of the value of WIDTH or FDIGITS. This feature is used by
;;; the ~E format directive to prevent complete loss of
;;; significance in the printed value due to a bogus choice of
;;; scale factor.
;;;
;;; Returns:
;;; (VALUES DIGIT-STRING DIGIT-LENGTH LEADING-POINT TRAILING-POINT DECPNT)
;;; where the results have the following interpretation:
;;;
;;; DIGIT-STRING - The decimal representation of X, with decimal point.
;;; DIGIT-LENGTH - The length of the string DIGIT-STRING.
;;; LEADING-POINT - True if the first character of DIGIT-STRING is the
;;; decimal point.
;;; TRAILING-POINT - True if the last character of DIGIT-STRING is the
;;; decimal point.
;;; POINT-POS - The position of the digit preceding the decimal
;;; point. Zero indicates point before first digit.
;;;
;;; NOTE: FLONUM-TO-STRING goes to a lot of trouble to guarantee
;;; accuracy. Specifically, the decimal number printed is the closest
;;; possible approximation to the true value of the binary number to
;;; be printed from among all decimal representations with the same
;;; number of digits. In free-format output, i.e. with the number of
;;; digits unconstrained, it is guaranteed that all the information is
;;; preserved, so that a properly- rounding reader can reconstruct the
;;; original binary number, bit-for-bit, from its printed decimal
;;; representation. Furthermore, only as many digits as necessary to
;;; satisfy this condition will be printed.
;;;
;;; FLOAT-DIGITS actually generates the digits for positive numbers;
;;; see below for comments.
(defun flonum-to-string (x &optional width fdigits scale fmin)
(declare (type float x))
(multiple-value-bind (e string)
(if fdigits
(flonum-to-digits x (min (- (+ fdigits (or scale 0)))
(- (or fmin 0))))
(if (and width (> width 1))
(let ((w (multiple-value-list
(flonum-to-digits x
(max 1
(+ (1- width)
(if (and scale (minusp scale))
scale 0)))
t)))
(f (multiple-value-list
(flonum-to-digits x (- (+ (or fmin 0)
(if scale scale 0)))))))
(cond
((>= (length (cadr w)) (length (cadr f)))
(values-list w))
(t (values-list f))))
(flonum-to-digits x)))
(let ((e (if (zerop x)
e
(+ e (or scale 0))))
(stream (make-string-output-stream)))
(if (plusp e)
(progn
(write-string string stream :end (min (length string) e))
(dotimes (i (- e (length string)))
(write-char #\0 stream))
(write-char #\. stream)
(write-string string stream :start (min (length string) e))
(when fdigits
(dotimes (i (- fdigits
(- (length string)
(min (length string) e))))
(write-char #\0 stream))))
(progn
(write-string "." stream)
(dotimes (i (- e))
(write-char #\0 stream))
(write-string string stream :end (when fdigits
(min (length string)
(max (or fmin 0)
(+ fdigits e)))))
(when fdigits
(dotimes (i (+ fdigits e (- (length string))))
(write-char #\0 stream)))))
(let ((string (get-output-stream-string stream)))
(values string (length string)
(char= (char string 0) #\.)
(char= (char string (1- (length string))) #\.)
(position #\. string))))))
;;; implementation of figure 1 from Burger and Dybvig, 1996. It is
;;; extended in order to handle rounding.
;;;
;;; As the implementation of the Dragon from Classic CMUCL (and
;;; previously in SBCL above FLONUM-TO-STRING) says: "DO NOT EVEN
;;; THINK OF ATTEMPTING TO UNDERSTAND THIS CODE WITHOUT READING THE
;;; PAPER!", and in this case we have to add that even reading the
;;; paper might not bring immediate illumination as CSR has attempted
;;; to turn idiomatic Scheme into idiomatic Lisp.
;;;
;;; FIXME: figure 1 from Burger and Dybvig is the unoptimized
;;; algorithm, noticeably slow at finding the exponent. Figure 2 has
;;; an improved algorithm, but CSR ran out of energy.
;;;
;;; possible extension for the enthusiastic: printing floats in bases
;;; other than base 10.
(defconstant single-float-min-e
(- 2 sb-vm:single-float-bias sb-vm:single-float-digits))
(defconstant double-float-min-e
(- 2 sb-vm:double-float-bias sb-vm:double-float-digits))
#+long-float
(defconstant long-float-min-e
(nth-value 1 (decode-float least-positive-long-float)))
;;; Call CHAR-FUN with the digits of FLOAT
;;; PROLOGUE-FUN and EPILOGUE-FUN are called with the exponent before
;;; and after printing to set up the state.
(declaim (inline %flonum-to-digits))
(defun %flonum-to-digits (char-fun
prologue-fun
epilogue-fun
float &optional position relativep)
(let ((print-base 10) ; B
(float-radix 2) ; b
(float-digits (float-digits float)) ; p
(min-e
(etypecase float
(single-float single-float-min-e)
(double-float double-float-min-e)
#+long-float
(long-float long-float-min-e))))
(multiple-value-bind (f e) (integer-decode-float float)
;; An extra step became necessary here for subnormals because the
;; algorithm assumes that the fraction is left-aligned in a field
;; that is FLOAT-DIGITS wide.
(when (< (float-precision float) float-digits)
(let ((shift (- float-digits (integer-length f))))
(setq f (ash f shift)
e (- e shift))))
(let ( ;; FIXME: these even tests assume normal IEEE rounding
;; mode. I wonder if we should cater for non-normal?
(high-ok (evenp f))
(low-ok (evenp f)))
(labels ((scale (r s m+ m-)
(do ((r+m+ (+ r m+))
(k 0 (1+ k))
(s s (* s print-base)))
((not (or (> r+m+ s)
(and high-ok (= r+m+ s))))
(do ((k k (1- k))
(r r (* r print-base))
(m+ m+ (* m+ print-base))
(m- m- (* m- print-base)))
((not (and (> r m-) ; Extension to handle zero
(let ((x (* (+ r m+) print-base)))
(or (< x s)
(and (not high-ok)
(= x s))))))
(funcall prologue-fun k)
(generate r s m+ m-)
(funcall epilogue-fun k))))))
(generate (r s m+ m-)
(let (d tc1 tc2)
(tagbody
loop
(setf (values d r) (truncate (* r print-base) s))
(setf m+ (* m+ print-base))
(setf m- (* m- print-base))
(setf tc1 (or (< r m-) (and low-ok (= r m-))))
(setf tc2 (let ((r+m+ (+ r m+)))
(or (> r+m+ s)
(and high-ok (= r+m+ s)))))
(when (or tc1 tc2)
(go end))
(funcall char-fun d)
(go loop)
end
(let ((d (cond
((and (not tc1) tc2) (1+ d))
((and tc1 (not tc2)) d)
((< (* r 2) s)
d)
(t
(1+ d)))))
(funcall char-fun d)))))
(initialize ()
(let (r s m+ m-)
(cond ((>= e 0)
(let ((be (expt float-radix e)))
(if (/= f (expt float-radix (1- float-digits)))
;; multiply F by 2 first, avoding consing two bignums
(setf r (* f 2 be)
s 2
m+ be
m- be)
(setf m- be
m+ (* be float-radix)
r (* f 2 m+)
s (* float-radix 2)))))
((or (= e min-e)
(/= f (expt float-radix (1- float-digits))))
(setf r (* f 2)
s (expt float-radix (- 1 e))
m+ 1
m- 1))
(t
(setf r (* f float-radix 2)
s (expt float-radix (- 2 e))
m+ float-radix
m- 1)))
(when position
(when relativep
(aver (> position 0))
(do ((k 0 (1+ k))
;; running out of letters here
(l 1 (* l print-base)))
((>= (* s l) (+ r m+))
;; k is now \hat{k}
(if (< (+ r (* s (/ (expt print-base (- k position)) 2)))
(* s l))
(setf position (- k position))
(setf position (- k position 1))))))
(let* ((x (/ (* s (expt print-base position)) 2))
(low (max m- x))
(high (max m+ x)))
(when (<= m- low)
(setf m- low)
(setf low-ok t))
(when (<= m+ high)
(setf m+ high)
(setf high-ok t))))
(values r s m+ m-))))
(multiple-value-bind (r s m+ m-) (initialize)
(scale r s m+ m-)))))))
(defun flonum-to-digits (float &optional position relativep)
(let ((digit-characters "0123456789"))
(with-push-char (:element-type base-char)
(%flonum-to-digits
(lambda (d)
(push-char (char digit-characters d)))
(lambda (k) k)
(lambda (k) (values k (get-pushed-string)))
float position relativep))))
(defun print-float (float stream)
(let ((position 0)
(dot-position 0)
(digit-characters "0123456789")
(e-min -3)
(e-max 8))
(%flonum-to-digits
(lambda (d)
(when (= position dot-position)
(write-char #\. stream))
(write-char (char digit-characters d) stream)
(incf position))
(lambda (k)
(cond ((not (< e-min k e-max))
(setf dot-position 1))
((plusp k)
(setf dot-position k))
(t
(setf dot-position -1)
(write-char #\0 stream)
(write-char #\. stream)
(loop for i below (- k)
do (write-char #\0 stream)))))
(lambda (k)
(when (<= position dot-position)
(loop for i below (- dot-position position)
do (write-char #\0 stream))
(write-char #\. stream)
(write-char #\0 stream))
(if (< e-min k e-max)
(print-float-exponent float 0 stream)
(print-float-exponent float (1- k) stream)))
float)))
;;; Given a non-negative floating point number, SCALE-EXPONENT returns
;;; a new floating point number Z in the range (0.1, 1.0] and an
;;; exponent E such that Z * 10^E is (approximately) equal to the
;;; original number. There may be some loss of precision due the
;;; floating point representation. The scaling is always done with
;;; long float arithmetic, which helps printing of lesser precisions
;;; as well as avoiding generic arithmetic.
;;;
;;; When computing our initial scale factor using EXPT, we pull out
;;; part of the computation to avoid over/under flow. When
;;; denormalized, we must pull out a large factor, since there is more
;;; negative exponent range than positive range.
(eval-when (:compile-toplevel :execute)
(setf *read-default-float-format*
#+long-float 'cl:long-float #-long-float 'cl:double-float))
(defun scale-exponent (original-x)
(let* ((x (coerce original-x 'long-float)))
(multiple-value-bind (sig exponent) (decode-float x)
(declare (ignore sig))
(if (= x $0.0e0)
(values (float $0.0e0 original-x) 1)
(let* ((ex (locally (declare (optimize (safety 0)))
(the fixnum
(round (* exponent
;; this is the closest double float
;; to (log 2 10), but expressed so
;; that we're not vulnerable to the
;; host lisp's interpretation of
;; arithmetic. (FIXME: it turns
;; out that sbcl itself is off by 1
;; ulp in this value, which is a
;; little unfortunate.)
#-long-float
(make-double-float 1070810131 1352628735)
#+long-float
(error "(log 2 10) not computed"))))))
(x (if (minusp ex)
(if (float-denormalized-p x)
#-long-float
(* x $1.0e16 (expt $10.0e0 (- (- ex) 16)))
#+long-float
(* x $1.0e18 (expt $10.0e0 (- (- ex) 18)))
(* x $10.0e0 (expt $10.0e0 (- (- ex) 1))))
(/ x $10.0e0 (expt $10.0e0 (1- ex))))))
(do ((d $10.0e0 (* d $10.0e0))
(y x (/ x d))
(ex ex (1+ ex)))
((< y $1.0e0)
(do ((m $10.0e0 (* m $10.0e0))
(z y (* y m))
(ex ex (1- ex)))
((>= z $0.1e0)
(values (float z original-x) ex))
(declare (long-float m) (integer ex))))
(declare (long-float d))))))))
(eval-when (:compile-toplevel :execute)
(setf *read-default-float-format* 'cl:single-float))
;;;; entry point for the float printer
;;; the float printer as called by PRINT, PRIN1, PRINC, etc. The
;;; argument is printed free-format, in either exponential or
;;; non-exponential notation, depending on its magnitude.
;;;
;;; NOTE: When a number is to be printed in exponential format, it is
;;; scaled in floating point. Since precision may be lost in this
;;; process, the guaranteed accuracy properties of FLONUM-TO-STRING
;;; are lost. The difficulty is that FLONUM-TO-STRING performs
;;; extensive computations with integers of similar magnitude to that
;;; of the number being printed. For large exponents, the bignums
;;; really get out of hand. If bignum arithmetic becomes reasonably
;;; fast and the exponent range is not too large, then it might become
;;; attractive to handle exponential notation with the same accuracy
;;; as non-exponential notation, using the method described in the
;;; Steele and White paper.
;;;
;;; NOTE II: this has been bypassed slightly by implementing Burger
;;; and Dybvig, 1996. When someone has time (KLUDGE) they can
;;; probably (a) implement the optimizations suggested by Burger and
;;; Dyvbig, and (b) remove all vestiges of Dragon4, including from
;;; fixed-format printing.
;;; Print the appropriate exponent marker for X and the specified exponent.
(defun print-float-exponent (x exp stream)
(declare (type float x) (type integer exp) (type stream stream))
(cond ((case *read-default-float-format*
((short-float single-float)
(typep x 'single-float))
((double-float #-long-float long-float)
(typep x 'double-float))
#+long-float
(long-float
(typep x 'long-float)))
(unless (eql exp 0)
(write-char #\e stream)
(%output-integer-in-base exp 10 stream)))
(t
(write-char
(etypecase x
(single-float #\f)
(double-float #\d)
(short-float #\s)
(long-float #\L))
stream)
(%output-integer-in-base exp 10 stream))))
(defmethod print-object ((x float) stream)
(cond
((float-infinity-or-nan-p x)
(if (float-infinity-p x)
(let ((symbol (etypecase x
(single-float (if (minusp x)
'single-float-negative-infinity
'single-float-positive-infinity))
(double-float (if (minusp x)
'double-float-negative-infinity
'double-float-positive-infinity)))))
(cond (*read-eval*
(write-string "#." stream)
(output-symbol symbol (sb-xc:symbol-package symbol) stream))
(t
(print-unreadable-object (x stream)
(output-symbol symbol (sb-xc:symbol-package symbol) stream)))))
(print-unreadable-object (x stream)
(princ (float-format-name x) stream)
(write-string (if (float-trapping-nan-p x) " trapping" " quiet") stream)
(write-string " NaN" stream))))
(t
(let ((x (cond ((minusp (float-sign x))
(write-char #\- stream)
(- x))
(t
x))))
(cond
((zerop x)
(write-string "0.0" stream)
(print-float-exponent x 0 stream))
(t
(print-float x stream)))))))
;;;; other leaf objects
;;; If *PRINT-ESCAPE* is false, just do a WRITE-CHAR, otherwise output
;;; the character name or the character in the #\char format.
(defmethod print-object ((char character) stream)
(if (or *print-escape* *print-readably*)
(let ((graphicp (and (graphic-char-p char)
(standard-char-p char)))
(name (char-name char)))
(write-string "#\\" stream)
(if (and name (or (not graphicp) *print-readably*))
(quote-string name stream)
(write-char char stream)))
(write-char char stream)))
(defmethod print-object ((sap system-area-pointer) stream)
(cond (*read-eval*
(format stream "#.(~S #X~8,'0X)" 'int-sap (sap-int sap)))
(t
(print-unreadable-object (sap stream)
(format stream "system area pointer: #X~8,'0X" (sap-int sap))))))
(defmethod print-object ((weak-pointer weak-pointer) stream)
(print-unreadable-object (weak-pointer stream)
(multiple-value-bind (value validp) (weak-pointer-value weak-pointer)
(cond (validp
(write-string "weak pointer: " stream)
(write value :stream stream))
(t
(write-string "broken weak pointer" stream))))))
(defmethod print-object ((component code-component) stream)
(print-unreadable-object (component stream :identity t)
(let (dinfo)
(cond ((code-obj-is-filler-p component)
(format stream "filler ~dw"
(ash (code-object-size component) (- sb-vm:word-shift))))
((eq (setq dinfo (%code-debug-info component)) :bpt-lra)
(write-string "bpt-trap-return" stream))
((functionp dinfo)
(format stream "trampoline ~S" dinfo))
(t
(format stream "code~@[ id=~x~] [~D]"
(%code-serialno component)
(code-n-entries component))
(let ((fun-name (awhen (%code-entry-point component 0)
(%simple-fun-name it))))
(when fun-name
(write-char #\Space stream)
(write fun-name :stream stream))
(cond ((not (typep dinfo 'sb-c::debug-info)))
((neq (sb-c::debug-info-name dinfo) fun-name)
(write-string ", " stream)
(output-object (sb-c::debug-info-name dinfo) stream)))))))))
#-(or x86 x86-64 arm64)
(defmethod print-object ((lra lra) stream)
(print-unreadable-object (lra stream :identity t)
(write-string "return PC object" stream)))
(defmethod print-object ((fdefn fdefn) stream)
(print-unreadable-object (fdefn stream :type t)
;; As fdefn names are particularly relevant to those hacking on the compiler
;; and disassembler, be maximally helpful by neither abbreviating (SETF ...)
;; due to length cutoff, nor failing to print a package if needed.
;; Some folks seem to love same-named symbols way too much.
(let ((*print-length* 20)) ; arbitrary
(prin1 (fdefn-name fdefn) stream))))
#+sb-simd-pack
(defmethod print-object ((pack simd-pack) stream)
(cond ((and *print-readably* *read-eval*)
(multiple-value-bind (format maker extractor)
(etypecase pack
((simd-pack double-float)
(values "#.(~S ~S ~S)"
'%make-simd-pack-double #'%simd-pack-doubles))
((simd-pack single-float)
(values "#.(~S ~S ~S ~S ~S)"
'%make-simd-pack-single #'%simd-pack-singles))
(t
(values "#.(~S #X~16,'0X #X~16,'0X)"
'%make-simd-pack-ub64 #'%simd-pack-ub64s)))
(multiple-value-call
#'format stream format maker (funcall extractor pack))))
(*print-readably*
(print-not-readable-error pack stream))
(t
(print-unreadable-object (pack stream)
(flet ((all-ones-p (value start end &aux (mask (- (ash 1 end) (ash 1 start))))
(= (logand value mask) mask))
(split-num (value start)
(loop
for i from 0 to 3
and v = (ash value (- start)) then (ash v -8)
collect (logand v #xFF))))
(multiple-value-bind (low high)
(%simd-pack-ub64s pack)
(etypecase pack
((simd-pack double-float)
(multiple-value-bind (v0 v1) (%simd-pack-doubles pack)
(format stream "~S~@{ ~:[~,13E~;~*TRUE~]~}"
'simd-pack
(all-ones-p low 0 64) v0
(all-ones-p high 0 64) v1)))
((simd-pack single-float)
(multiple-value-bind (v0 v1 v2 v3) (%simd-pack-singles pack)
(format stream "~S~@{ ~:[~,7E~;~*TRUE~]~}"
'simd-pack
(all-ones-p low 0 32) v0
(all-ones-p low 32 64) v1
(all-ones-p high 0 32) v2
(all-ones-p high 32 64) v3)))
(t
(format stream "~S~@{ ~{ ~2,'0X~}~}"
'simd-pack
(split-num low 0) (split-num low 32)
(split-num high 0) (split-num high 32))))))))))
#+sb-simd-pack-256
(defmethod print-object ((pack simd-pack-256) stream)
(cond ((and *print-readably* *read-eval*)
(multiple-value-bind (format maker extractor)
(etypecase pack
((simd-pack-256 double-float)
(values "#.(~@{~S~^ ~})"
'%make-simd-pack-256-double #'%simd-pack-256-doubles))
((simd-pack-256 single-float)
(values "#.(~@{~S~^ ~})"
'%make-simd-pack-256-single #'%simd-pack-256-singles))
(t
(values "#.(~S~@{ #X~16,'0X~})"
'%make-simd-pack-256-ub64 #'%simd-pack-256-ub64s)))
(multiple-value-call
#'format stream format maker (funcall extractor pack))))
(*print-readably*
(print-not-readable-error pack stream))
(t
(print-unreadable-object (pack stream)
(etypecase pack
((simd-pack-256 double-float)
(multiple-value-call #'format stream "~S~@{ ~,13E~}"
'simd-pack-256
(%simd-pack-256-doubles pack)))
((simd-pack-256 single-float)
(multiple-value-call #'format stream "~S~@{ ~,7E~}"
'simd-pack-256
(%simd-pack-256-singles pack)))
(t
(multiple-value-bind (p0 p1 p2 p3)
(%simd-pack-256-ub64s pack)
(format stream "~S~@{ ~16,'0X~}"
'simd-pack-256
p0 p1 p2 p3))))))))
;;;; functions
(defmethod print-object ((object function) stream)
(let* ((name (%fun-name object))
(proper-name-p (and (legal-fun-name-p name) (fboundp name)
(eq (fdefinition name) object))))
;; ":TYPE T" is no good, since CLOSURE doesn't have full-fledged status.
(print-unreadable-object (object stream :identity (not proper-name-p))
(format stream "~A~@[ ~S~]"
;; CLOSURE and SIMPLE-FUN should print as #<FUNCTION>
;; but anything else prints as its exact type.
(if (funcallable-instance-p object) (type-of object) 'function)
name))))
;;;; catch-all for unknown things
(declaim (inline lowtag-of))
(defun lowtag-of (x) (logand (get-lisp-obj-address x) sb-vm:lowtag-mask))
(defmethod print-object ((object t) stream)
(when (eq object sb-pcl:+slot-unbound+)
;; If specifically the unbound marker with 0 data,
;; as opposed to any other unbound marker.
(print-unreadable-object (object stream) (write-string "unbound" stream))
(return-from print-object))
(when (eql (get-lisp-obj-address object) sb-vm:no-tls-value-marker-widetag)
(print-unreadable-object (object stream) (write-string "novalue" stream))
(return-from print-object))
(print-unreadable-object (object stream :identity t)
(let ((lowtag (lowtag-of object)))
(case lowtag
(#.sb-vm:other-pointer-lowtag
(let ((widetag (widetag-of object)))
(case widetag
(#.sb-vm:value-cell-widetag
(write-string "value cell " stream)
(output-object (value-cell-ref object) stream))
(#.sb-vm:filler-widetag
(write-string "pad " stream)
(write (1+ (get-header-data object)) :stream stream)
(write-string "w" stream)) ; words
(t
(write-string "unknown pointer object, widetag=" stream)
(output-integer widetag stream 16 t)))))
((#.sb-vm:fun-pointer-lowtag
#.sb-vm:instance-pointer-lowtag
#.sb-vm:list-pointer-lowtag)
(write-string "unknown pointer object, lowtag=" stream)
(output-integer lowtag stream 16 t))
(t
(case (widetag-of object)
(#.sb-vm:unbound-marker-widetag
(write-string "unbound marker" stream))
(t
(write-string "unknown immediate object, lowtag=" stream)
(output-integer lowtag stream 2 t)
(write-string ", widetag=" stream)
(output-integer (widetag-of object) stream 16 t))))))))