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;;;; 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
;;; FIXME: Many of these have nontrivial types, e.g. *PRINT-LEVEL*,
;;; *PRINT-LENGTH*, and *PRINT-LINES* are (OR NULL UNSIGNED-BYTE).
(defvar *print-readably* nil
#!+sb-doc
"If true, all objects will printed readably. If readable printing is
impossible, an error will be signalled. This overrides the value of
*PRINT-ESCAPE*.")
(defvar *print-escape* T
#!+sb-doc
"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)
#!+sb-doc
"Should pretty printing be used?")
(defvar *print-base* 10.
#!+sb-doc
"the output base for RATIONALs (including integers)")
(defvar *print-radix* nil
#!+sb-doc
"Should base be verified when printing RATIONALs?")
(defvar *print-level* nil
#!+sb-doc
"How many levels should be printed before abbreviating with \"#\"?")
(defvar *print-length* nil
#!+sb-doc
"How many elements at any level should be printed before abbreviating
with \"...\"?")
(defvar *print-circle* nil
#!+sb-doc
"Should we use #n= and #n# notation to preserve uniqueness in general (and
circularity in particular) when printing?")
(defvar *print-case* :upcase
#!+sb-doc
"What case should the printer should use default?")
(defvar *print-array* t
#!+sb-doc
"Should the contents of arrays be printed?")
(defvar *print-gensym* t
#!+sb-doc
"Should #: prefixes be used when printing symbols with null SYMBOL-PACKAGE?")
(defvar *print-lines* nil
#!+sb-doc
"the maximum number of lines to print per object")
(defvar *print-right-margin* nil
#!+sb-doc
"the position of the right margin in ems (for pretty-printing)")
(defvar *print-miser-width* nil
#!+sb-doc
"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-doc
(setf (fdocumentation '*print-pprint-dispatch* 'variable)
"the pprint-dispatch-table that controls how to pretty-print objects")
(defmacro with-standard-io-syntax (&body body)
#!+sb-doc
"Bind the reader and printer control variables to values that enable READ
to reliably read the results of PRINT. These values are:
*PACKAGE* the COMMON-LISP-USER package
*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-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* the standard readtable"
`(%with-standard-io-syntax (lambda () ,@body)))
(defun %with-standard-io-syntax (function)
(declare (type function 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-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)
;; FIXME: It doesn't seem like a good idea to expose our
;; disaster-recovery *STANDARD-READTABLE* here. What if some
;; enterprising user corrupts the disaster-recovery readtable
;; by doing destructive readtable operations within
;; WITH-STANDARD-IO-SYNTAX? Perhaps we should do a
;; COPY-READTABLE? The consing would be unfortunate, though.
(*readtable* *standard-readtable*))
(funcall function)))
;;;; routines to print objects
(defun write (object &key
((:stream stream) *standard-output*)
((: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*))
#!+sb-doc
"Output OBJECT to the specified stream, defaulting to *STANDARD-OUTPUT*"
(output-object object (out-synonym-of stream))
object)
(defun prin1 (object &optional stream)
#!+sb-doc
"Output a mostly READable printed representation of OBJECT on the specified
STREAM."
(let ((*print-escape* T))
(output-object object (out-synonym-of stream)))
object)
(defun princ (object &optional stream)
#!+sb-doc
"Output an aesthetic but not necessarily READable printed representation
of OBJECT on the specified STREAM."
(let ((*print-escape* NIL)
(*print-readably* NIL))
(output-object object (out-synonym-of stream)))
object)
(defun print (object &optional stream)
#!+sb-doc
"Output a newline, the mostly READable printed representation of OBJECT, and
space to the specified STREAM."
(let ((stream (out-synonym-of stream)))
(terpri stream)
(prin1 object stream)
(write-char #\space stream)
object))
(defun pprint (object &optional stream)
#!+sb-doc
"Prettily output OBJECT preceded by a newline."
(let ((*print-pretty* t)
(*print-escape* t)
(stream (out-synonym-of stream)))
(terpri stream)
(output-object object stream))
(values))
(defun write-to-string
(object &key
((: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*))
#!+sb-doc
"Return the printed representation of OBJECT as a string."
(stringify-object object))
(defun prin1-to-string (object)
#!+sb-doc
"Return the printed representation of OBJECT as a string with
slashification on."
(stringify-object object t))
(defun princ-to-string (object)
#!+sb-doc
"Return the printed representation of OBJECT as a string with
slashification off."
(stringify-object object nil))
;;; This produces the printed representation of an object as a string.
;;; The few ...-TO-STRING functions above call this.
(defvar *string-output-streams* ())
(defun stringify-object (object &optional (*print-escape* *print-escape*))
(let ((stream (if *string-output-streams*
(pop *string-output-streams*)
(make-string-output-stream))))
(setup-printer-state)
(output-object object stream)
(prog1
(get-output-stream-string stream)
(push stream *string-output-streams*))))
;;;; support for the PRINT-UNREADABLE-OBJECT macro
;;; guts of PRINT-UNREADABLE-OBJECT
(defun %print-unreadable-object (object stream type identity body)
(declare (type (or null function) body))
(when *print-readably*
(error 'print-not-readable :object object))
(flet ((print-description ()
(when type
(write (type-of object) :stream stream :circle nil
:level nil :length nil)
(when (or body identity)
(write-char #\space stream)
(pprint-newline :fill stream)))
(when body
(funcall body))
(when identity
(when body
(write-char #\space stream)
(pprint-newline :fill stream))
(write-char #\{ stream)
(write (get-lisp-obj-address object) :stream stream
:radix nil :base 16)
(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)
;;;; circularity detection stuff
;;; When *PRINT-CIRCLE* is T, this gets bound to a hash table that
;;; (eventually) ends up with entries for every object printed. When
;;; we are initially looking for circularities, we enter a T when we
;;; find an object for the first time, and a 0 when we encounter an
;;; object a second time around. When we are actually printing, the 0
;;; entries get changed to the actual marker value when they are first
;;; printed.
(defvar *circularity-hash-table* nil)
;;; When NIL, we are just looking for circularities. After we have
;;; found them all, this gets bound to 0. Then whenever we need a new
;;; marker, it is incremented.
(defvar *circularity-counter* nil)
;;; Check to see whether OBJECT is a circular reference, and return
;;; something non-NIL if it is. If ASSIGN is T, then the number to use
;;; in the #n= and #n# noise is assigned at this time.
;;; If ASSIGN is true, reference bookkeeping will only be done for
;;; existing entries, no new references will be recorded!
;;;
;;; Note: CHECK-FOR-CIRCULARITY must be called *exactly* once with
;;; ASSIGN true, or the circularity detection noise will get confused
;;; about when to use #n= and when to use #n#. If this returns non-NIL
;;; when ASSIGN is true, then you must call HANDLE-CIRCULARITY on it.
;;; If CHECK-FOR-CIRCULARITY returns :INITIATE as the second value,
;;; you need to initiate the circularity detection noise, e.g. bind
;;; *CIRCULARITY-HASH-TABLE* and *CIRCULARITY-COUNTER* to suitable values
;;; (see #'OUTPUT-OBJECT for an example).
(defun check-for-circularity (object &optional assign)
(cond ((null *print-circle*)
;; Don't bother, nobody cares.
nil)
((null *circularity-hash-table*)
(values nil :initiate))
((null *circularity-counter*)
(ecase (gethash object *circularity-hash-table*)
((nil)
;; first encounter
(setf (gethash object *circularity-hash-table*) t)
;; We need to keep looking.
nil)
((t)
;; second encounter
(setf (gethash object *circularity-hash-table*) 0)
;; It's a circular reference.
t)
(0
;; It's a circular reference.
t)))
(t
(let ((value (gethash object *circularity-hash-table*)))
(case value
((nil t)
;; If NIL, we found an object that wasn't there the
;; first time around. If T, this object appears exactly
;; once. Either way, just print the thing without any
;; special processing. Note: you might argue that
;; finding a new object means that something is broken,
;; but this can happen. If someone uses the ~@<...~:>
;; format directive, it conses a new list each time
;; though format (i.e. the &REST list), so we will have
;; different cdrs.
nil)
(0
(if assign
(let ((value (incf *circularity-counter*)))
;; first occurrence of this object: Set the counter.
(setf (gethash object *circularity-hash-table*) value)
value)
t))
(t
;; second or later occurrence
(- value)))))))
;;; Handle the results of CHECK-FOR-CIRCULARITY. If this returns T then
;;; you should go ahead and print the object. If it returns NIL, then
;;; you should blow it off.
(defun handle-circularity (marker stream)
(case marker
(:initiate
;; Someone forgot to initiate circularity detection.
(let ((*print-circle* nil))
(error "trying to use CHECK-FOR-CIRCULARITY when ~
circularity checking isn't initiated")))
((t)
;; It's a second (or later) reference to the object while we are
;; just looking. So don't bother groveling it again.
nil)
(t
(write-char #\# stream)
(let ((*print-base* 10) (*print-radix* nil))
(cond ((minusp marker)
(output-integer (- marker) stream)
(write-char #\# stream)
nil)
(t
(output-integer marker stream)
(write-char #\= stream)
t))))))
;;;; 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)
(symbol-package x))))
;;; Output OBJECT to STREAM observing all printer control variables.
(defun output-object (object stream)
(labels ((print-it (stream)
(if *print-pretty*
(sb!pretty:output-pretty-object object stream)
(output-ugly-object object stream)))
(check-it (stream)
(multiple-value-bind (marker initiate)
(check-for-circularity object t)
;; initialization of the circulation detect noise ...
(if (eq initiate :initiate)
(let ((*circularity-hash-table*
(make-hash-table :test 'eq)))
(check-it (make-broadcast-stream))
(let ((*circularity-counter* 0))
(check-it stream)))
;; otherwise
(if marker
(when (handle-circularity marker stream)
(print-it stream))
(print-it stream))))))
(cond (;; Maybe we don't need to bother with circularity detection.
(or (not *print-circle*)
(uniquely-identified-by-print-p object))
(print-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
(print-it stream)))))
;;; a hack to work around recurring gotchas with printing while
;;; DEFGENERIC PRINT-OBJECT is being built
;;;
;;; (hopefully will go away naturally when CLOS moves into cold init)
(defvar *print-object-is-disabled-p*)
;;; 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 (object stream)
(typecase object
;; KLUDGE: The TYPECASE approach here is non-ANSI; the ANSI definition of
;; PRINT-OBJECT says it provides printing and we're supposed to provide
;; PRINT-OBJECT methods covering all classes. We deviate from this
;; by using PRINT-OBJECT only when we print instance values. However,
;; ANSI makes it hard to tell that we're deviating from this:
;; (1) ANSI specifies that the user isn't supposed to call PRINT-OBJECT
;; directly.
;; (2) ANSI (section 11.1.2.1.2) says it's undefined to define
;; a method on an external symbol in the CL package which is
;; applicable to arg lists containing only direct instances of
;; standardized classes.
;; Thus, in order for the user to detect our sleaziness in conforming
;; code, he has to do something relatively obscure like
;; (1) actually use tools like FIND-METHOD to look for PRINT-OBJECT
;; methods, or
;; (2) define a PRINT-OBJECT method which is specialized on the stream
;; value (e.g. a Gray stream object).
;; As long as no one comes up with a non-obscure way of detecting this
;; sleaziness, fixing this nonconformity will probably have a low
;; priority. -- WHN 2001-11-25
(fixnum
(output-integer object stream))
(list
(if (null object)
(output-symbol object stream)
(output-list object stream)))
(instance
(cond ((not (and (boundp '*print-object-is-disabled-p*)
*print-object-is-disabled-p*))
(print-object object stream))
((typep object 'structure-object)
(default-structure-print object stream *current-level-in-print*))
(t
(write-string "#<INSTANCE but not STRUCTURE-OBJECT>" stream))))
(function
(unless (and (funcallable-instance-p object)
(printed-as-funcallable-standard-class object stream))
(output-fun object stream)))
(symbol
(output-symbol object stream))
(number
(etypecase object
(integer
(output-integer object stream))
(float
(output-float object stream))
(ratio
(output-ratio object stream))
(ratio
(output-ratio object stream))
(complex
(output-complex object stream))))
(character
(output-character object stream))
(vector
(output-vector object stream))
(array
(output-array object stream))
(system-area-pointer
(output-sap object stream))
(weak-pointer
(output-weak-pointer object stream))
(lra
(output-lra object stream))
(code-component
(output-code-component object stream))
(fdefn
(output-fdefn object stream))
(t
(output-random object stream))))
;;;; symbols
;;; values of *PRINT-CASE* and (READTABLE-CASE *READTABLE*) the last
;;; time the printer was called
(defvar *previous-case* nil)
(defvar *previous-readtable-case* nil)
;;; This variable contains the current definition of one of three
;;; symbol printers. SETUP-PRINTER-STATE sets this variable.
(defvar *internal-symbol-output-fun* nil)
;;; This function sets the internal global symbol
;;; *INTERNAL-SYMBOL-OUTPUT-FUN* to the right function depending on
;;; the value of *PRINT-CASE*. See the manual for details. The print
;;; buffer stream is also reset.
(defun setup-printer-state ()
(unless (and (eq *print-case* *previous-case*)
(eq (readtable-case *readtable*) *previous-readtable-case*))
(setq *previous-case* *print-case*)
(setq *previous-readtable-case* (readtable-case *readtable*))
(unless (member *print-case* '(:upcase :downcase :capitalize))
(setq *print-case* :upcase)
(error "invalid *PRINT-CASE* value: ~S" *previous-case*))
(unless (member *previous-readtable-case*
'(:upcase :downcase :invert :preserve))
(setf (readtable-case *readtable*) :upcase)
(error "invalid READTABLE-CASE value: ~S" *previous-readtable-case*))
(setq *internal-symbol-output-fun*
(case *previous-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)))))
;;; Output PNAME (a symbol-name or package-name) surrounded with |'s,
;;; and with any embedded |'s or \'s escaped.
(defun output-quoted-symbol-name (pname stream)
(write-char #\| stream)
(dotimes (index (length pname))
(let ((char (schar pname index)))
(when (or (char= char #\\) (char= char #\|))
(write-char #\\ stream))
(write-char char stream)))
(write-char #\| stream))
(defun output-symbol (object stream)
(if (or *print-escape* *print-readably*)
(let ((package (symbol-package object))
(name (symbol-name object)))
(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 (sane-package)))
;; Uninterned symbols print with a leading #:.
((null package)
(when (or *print-gensym* *print-readably*)
(write-string "#:" stream)))
(t
(multiple-value-bind (symbol accessible)
(find-symbol name (sane-package))
;; 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.
(unless (and accessible (eq symbol object))
(output-symbol-name (package-name package) stream)
(multiple-value-bind (symbol externalp)
(find-external-symbol name package)
(declare (ignore symbol))
(if externalp
(write-char #\: stream)
(write-string "::" stream)))))))
(output-symbol-name name stream))
(output-symbol-name (symbol-name object) stream nil)))
;;; Output the string NAME as if it were a symbol name. In other
;;; words, diddle its case according to *PRINT-CASE* and
;;; READTABLE-CASE.
(defun output-symbol-name (name stream &optional (maybe-quote t))
(declare (type simple-string name))
(setup-printer-state)
(if (and maybe-quote (symbol-quotep name))
(output-quoted-symbol-name name stream)
(funcall *internal-symbol-output-fun* name stream)))
;;;; 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. At characters have at least one bit set, so we can
;;; search for any character with a positive test.
(defvar *character-attributes*
(make-array char-code-limit
:element-type '(unsigned-byte 16)
:initial-element 0))
(declaim (type (simple-array (unsigned-byte 16) (#.char-code-limit))
*character-attributes*))
;;; 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.
(eval-when (:compile-toplevel :load-toplevel :execute)
;;; LETTER-ATTRIBUTE is a local of SYMBOL-QUOTEP. It matches letters
;;; that don't need to be escaped (according to READTABLE-CASE.)
(defparameter *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)))
) ; EVAL-WHEN
(flet ((set-bit (char bit)
(let ((code (char-code char)))
(setf (aref *character-attributes* code)
(logior bit (aref *character-attributes* 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 char-code-limit)
(when (zerop (aref *character-attributes* i))
(setf (aref *character-attributes* i) funny-attribute))))
;;; For each character, the value of the corresponding element is the
;;; lowest base in which that character is a digit.
(defvar *digit-bases*
(make-array char-code-limit
:element-type '(unsigned-byte 8)
:initial-element 36))
(declaim (type (simple-array (unsigned-byte 8) (#.char-code-limit))
*digit-bases*))
(dotimes (i 36)
(let ((char (digit-char i 36)))
(setf (aref *digit-bases* (char-code char)) i)))
;;; A FSM-like thingie that determines whether a symbol is a potential
;;; number or has evil characters in it.
(defun symbol-quotep (name)
(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 (aref attributes code))
(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 ()
`(< (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*)
(:upcase uppercase-attribute)
(: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 (aref attributes (char-code (schar name i)))
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))))
;;;; *INTERNAL-SYMBOL-OUTPUT-FUN*
;;;;
;;;; case hackery: These functions are stored in
;;;; *INTERNAL-SYMBOL-OUTPUT-FUN* 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)
(declare (simple-string pname))
(write-string pname stream))
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :UPCASE :DOWNCASE
(defun output-lowercase-symbol (pname stream)
(declare (simple-string pname))
(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)
(declare (simple-string pname))
(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)
(declare (simple-string pname))
(let ((prev-not-alpha t)
(up (eq (readtable-case *readtable*) :upcase)))
(dotimes (i (length pname))
(let ((char (char pname i)))
(write-char (if up
(if (or prev-not-alpha (lower-case-p char))
char
(char-downcase char))
(if prev-not-alpha
(char-upcase char)
char))
stream)
(setq prev-not-alpha (not (alpha-char-p char)))))))
;;; called when:
;;; READTABLE-CASE *PRINT-CASE*
;;; :INVERT any
(defun output-invert-symbol (pname stream)
(declare (simple-string pname))
(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))
(all-lower (output-uppercase-symbol pname stream))
(t
(write-string pname stream)))))
#|
(defun test1 ()
(let ((*readtable* (copy-readtable nil)))
(format t "READTABLE-CASE Input Symbol-name~@
----------------------------------~%")
(dolist (readtable-case '(:upcase :downcase :preserve :invert))
(setf (readtable-case *readtable*) readtable-case)
(dolist (input '("ZEBRA" "Zebra" "zebra"))
(format t "~&:~A~16T~A~24T~A"
(string-upcase readtable-case)
input
(symbol-name (read-from-string input)))))))
(defun test2 ()
(let ((*readtable* (copy-readtable nil)))
(format t "READTABLE-CASE *PRINT-CASE* Symbol-name Output Princ~@
--------------------------------------------------------~%")
(dolist (readtable-case '(:upcase :downcase :preserve :invert))
(setf (readtable-case *readtable*) readtable-case)
(dolist (*print-case* '(:upcase :downcase :capitalize))
(dolist (symbol '(|ZEBRA| |Zebra| |zebra|))
(format t "~&:~A~15T:~A~29T~A~42T~A~50T~A"
(string-upcase readtable-case)
(string-upcase *print-case*)
(symbol-name symbol)
(prin1-to-string symbol)
(princ-to-string symbol)))))))
|#
;;;; recursive objects
(defun output-list (list 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)))
(defun output-vector (vector stream)
(declare (vector vector))
(cond ((stringp vector)
(cond ((or *print-escape* *print-readably*)
(write-char #\" stream)
(quote-string vector stream)
(write-char #\" stream))
(t
(write-string vector stream))))
((not (or *print-array* *print-readably*))
(output-terse-array vector stream))
((bit-vector-p vector)
(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)))
(t
(when (and *print-readably*
(not (array-readably-printable-p vector)))
(error 'print-not-readable :object 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)))))
;;; 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 (length string)))
(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.
(defun output-array (array stream)
(if (or *print-array* *print-readably*)
(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))
(print-unreadable-object (array stream :type t :identity t))))
;;; Output the readable #A form of an array.
(defun output-array-guts (array stream)
(when (and *print-readably*
(not (array-readably-printable-p array)))
(error 'print-not-readable :object array))
(write-char #\# stream)
(let ((*print-base* 10))
(output-integer (array-rank array) stream))
(write-char #\A stream)
(with-array-data ((data array) (start) (end))
(declare (ignore end))
(sub-output-array-guts data (array-dimensions array) stream start)))
(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)))))
;;; a trivial non-generic-function placeholder for PRINT-OBJECT, for
;;; use until CLOS is set up (at which time it will be replaced with
;;; the real generic function implementation)
(defun print-object (instance stream)
(default-structure-print instance stream *current-level-in-print*))
;;;; integer, ratio, and complex printing (i.e. everything but floats)
(defun output-integer (integer stream)
;; FIXME: This UNLESS form should be pulled out into something like
;; (SANE-PRINT-BASE), along the lines of (SANE-PACKAGE) for the
;; *PACKAGE* variable.
(unless (and (fixnump *print-base*)
(< 1 *print-base* 37))
(let ((obase *print-base*))
(setq *print-base* 10.)
(error "~A is not a reasonable value for *PRINT-BASE*." obase)))
(when (and (not (= *print-base* 10.))
*print-radix*)
;; First print leading base information, if any.
(write-char #\# stream)
(write-char (case *print-base*
(2. #\b)
(8. #\o)
(16. #\x)
(T (let ((fixbase *print-base*)
(*print-base* 10.)
(*print-radix* ()))
(sub-output-integer fixbase stream))
#\r))
stream))
;; Then output a minus sign if the number is negative, then output
;; the absolute value of the number.
(cond ((bignump integer) (print-bignum integer stream))
((< integer 0)
(write-char #\- stream)
(sub-output-integer (- integer) stream))
(t
(sub-output-integer integer stream)))
;; Print any trailing base information, if any.
(if (and (= *print-base* 10.) *print-radix*)
(write-char #\. stream)))
(defun sub-output-integer (integer stream)
(let ((quotient ())
(remainder ()))
;; Recurse until you have all the digits pushed on the stack.
(if (not (zerop (multiple-value-setq (quotient remainder)
(truncate integer *print-base*))))
(sub-output-integer quotient stream))
;; Then as each recursive call unwinds, turn the digit (in remainder)
;; into a character and output the character.
(write-char (code-char (if (and (> remainder 9.)
(> *print-base* 10.))
(+ (char-code #\A) (- remainder 10.))
(+ (char-code #\0) remainder)))
stream)))
;;;; bignum printing
;;; *BASE-POWER* holds the number that we keep dividing into the
;;; bignum for each *print-base*. We want this number as close to
;;; *most-positive-fixnum* as possible, i.e. (floor (log
;;; most-positive-fixnum *print-base*)).
(defparameter *base-power* (make-array 37 :initial-element nil))
;;; *FIXNUM-POWER--1* holds the number of digits for each *PRINT-BASE*
;;; that fit in the corresponding *base-power*.
(defparameter *fixnum-power--1* (make-array 37 :initial-element nil))
;;; Print the bignum to the stream. We first generate the correct
;;; value for *base-power* and *fixnum-power--1* if we have not
;;; already. Then we call bignum-print-aux to do the printing.
(defun print-bignum (big stream)
(unless (aref *base-power* *print-base*)
(do ((power-1 -1 (1+ power-1))
(new-divisor *print-base* (* new-divisor *print-base*))
(divisor 1 new-divisor))
((not (fixnump new-divisor))
(setf (aref *base-power* *print-base*) divisor)
(setf (aref *fixnum-power--1* *print-base*) power-1))))
(bignum-print-aux (cond ((minusp big)
(write-char #\- stream)
(- big))
(t big))
(aref *base-power* *print-base*)
(aref *fixnum-power--1* *print-base*)
stream)
big)
(defun bignum-print-aux (big divisor power-1 stream)
(multiple-value-bind (newbig fix) (truncate big divisor)
(if (fixnump newbig)
(sub-output-integer newbig stream)
(bignum-print-aux newbig divisor power-1 stream))
(do ((zeros power-1 (1- zeros))
(base-power *print-base* (* base-power *print-base*)))
((> base-power fix)
(dotimes (i zeros) (write-char #\0 stream))
(sub-output-integer fix stream)))))
(defun output-ratio (ratio stream)
(when *print-radix*
(write-char #\# stream)
(case *print-base*
(2 (write-char #\b stream))
(8 (write-char #\o stream))
(16 (write-char #\x stream))
(t (write *print-base* :stream stream :radix nil :base 10)))
(write-char #\r stream))
(let ((*print-radix* nil))
(output-integer (numerator ratio) stream)
(write-char #\/ stream)
(output-integer (denominator ratio) stream)))
(defun output-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 the
;;; printer and 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.
;;;
;;; Most of the optional arguments are for the benefit for FORMAT and are not
;;; used by the printer.
;;;
;;; 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-STRING actually generates the digits for positive numbers.
;;; The algorithm is essentially that of algorithm Dragon4 in "How to
;;; Print Floating-Point Numbers Accurately" by Steele and White. The
;;; current (draft) version of this paper may be found in
;;; [CMUC]<steele>tradix.press. DO NOT EVEN THINK OF ATTEMPTING TO
;;; UNDERSTAND THIS CODE WITHOUT READING THE PAPER!
(defvar *digits* "0123456789")
(defun flonum-to-string (x &optional width fdigits scale fmin)
(cond ((zerop x)
;; Zero is a special case which FLOAT-STRING cannot handle.
(if fdigits
(let ((s (make-string (1+ fdigits) :initial-element #\0)))
(setf (schar s 0) #\.)
(values s (length s) t (zerop fdigits) 0))
(values "." 1 t t 0)))
(t
(multiple-value-bind (sig exp) (integer-decode-float x)
(let* ((precision (float-precision x))
(digits (float-digits x))
(fudge (- digits precision))
(width (if width (max width 1) nil)))
(float-string (ash sig (- fudge)) (+ exp fudge) precision width
fdigits scale fmin))))))
(defun float-string (fraction exponent precision width fdigits scale fmin)
(let ((r fraction) (s 1) (m- 1) (m+ 1) (k 0)
(digits 0) (decpnt 0) (cutoff nil) (roundup nil) u low high
(digit-string (make-array 50
:element-type 'base-char
:fill-pointer 0
:adjustable t)))
;; Represent fraction as r/s, error bounds as m+/s and m-/s.
;; Rational arithmetic avoids loss of precision in subsequent
;; calculations.
(cond ((> exponent 0)
(setq r (ash fraction exponent))
(setq m- (ash 1 exponent))
(setq m+ m-))
((< exponent 0)
(setq s (ash 1 (- exponent)))))
;; Adjust the error bounds m+ and m- for unequal gaps.
(when (= fraction (ash 1 precision))
(setq m+ (ash m+ 1))
(setq r (ash r 1))
(setq s (ash s 1)))
;; Scale value by requested amount, and update error bounds.
(when scale
(if (minusp scale)
(let ((scale-factor (expt 10 (- scale))))
(setq s (* s scale-factor)))
(let ((scale-factor (expt 10 scale)))
(setq r (* r scale-factor))
(setq m+ (* m+ scale-factor))
(setq m- (* m- scale-factor)))))
;; Scale r and s and compute initial k, the base 10 logarithm of r.
(do ()
((>= r (ceiling s 10)))
(decf k)
(setq r (* r 10))
(setq m- (* m- 10))
(setq m+ (* m+ 10)))
(do ()(nil)
(do ()
((< (+ (ash r 1) m+) (ash s 1)))
(setq s (* s 10))
(incf k))
;; Determine number of fraction digits to generate.
(cond (fdigits
;; Use specified number of fraction digits.
(setq cutoff (- fdigits))
;;don't allow less than fmin fraction digits
(if (and fmin (> cutoff (- fmin))) (setq cutoff (- fmin))))
(width
;; Use as many fraction digits as width will permit but
;; force at least fmin digits even if width will be
;; exceeded.
(if (< k 0)
(setq cutoff (- 1 width))
(setq cutoff (1+ (- k width))))
(if (and fmin (> cutoff (- fmin))) (setq cutoff (- fmin)))))
;; If we decided to cut off digit generation before precision
;; has been exhausted, rounding the last digit may cause a carry
;; propagation. We can prevent this, preserving left-to-right
;; digit generation, with a few magical adjustments to m- and
;; m+. Of course, correct rounding is also preserved.
(when (or fdigits width)
(let ((a (- cutoff k))
(y s))
(if (>= a 0)
(dotimes (i a) (setq y (* y 10)))
(dotimes (i (- a)) (setq y (ceiling y 10))))
(setq m- (max y m-))
(setq m+ (max y m+))
(when (= m+ y) (setq roundup t))))
(when (< (+ (ash r 1) m+) (ash s 1)) (return)))
;; Zero-fill before fraction if no integer part.
(when (< k 0)
(setq decpnt digits)
(vector-push-extend #\. digit-string)
(dotimes (i (- k))
(incf digits) (vector-push-extend #\0 digit-string)))
;; Generate the significant digits.
(do ()(nil)
(decf k)
(when (= k -1)
(vector-push-extend #\. digit-string)
(setq decpnt digits))
(multiple-value-setq (u r) (truncate (* r 10) s))
(setq m- (* m- 10))
(setq m+ (* m+ 10))
(setq low (< (ash r 1) m-))
(if roundup
(setq high (>= (ash r 1) (- (ash s 1) m+)))
(setq high (> (ash r 1) (- (ash s 1) m+))))
;; Stop when either precision is exhausted or we have printed as
;; many fraction digits as permitted.
(when (or low high (and cutoff (<= k cutoff))) (return))
(vector-push-extend (char *digits* u) digit-string)
(incf digits))
;; If cutoff occurred before first digit, then no digits are
;; generated at all.
(when (or (not cutoff) (>= k cutoff))
;; Last digit may need rounding
(vector-push-extend (char *digits*
(cond ((and low (not high)) u)
((and high (not low)) (1+ u))
(t (if (<= (ash r 1) s) u (1+ u)))))
digit-string)
(incf digits))
;; Zero-fill after integer part if no fraction.
(when (>= k 0)
(dotimes (i k) (incf digits) (vector-push-extend #\0 digit-string))
(vector-push-extend #\. digit-string)
(setq decpnt digits))
;; Add trailing zeroes to pad fraction if fdigits specified.
(when fdigits
(dotimes (i (- fdigits (- digits decpnt)))
(incf digits)
(vector-push-extend #\0 digit-string)))
;; all done
(values digit-string (1+ digits) (= decpnt 0) (= decpnt digits) decpnt)))
;;; 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 'long-float #!-long-float '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 (round (* exponent (log 2e0 10))))
(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))))))))))
(eval-when (:compile-toplevel :execute)
(setf *read-default-float-format* '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.
;;; 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))
(let ((*print-radix* nil)
(plusp (plusp exp)))
(if (typep x *read-default-float-format*)
(unless (eql exp 0)
(format stream "e~:[~;+~]~D" plusp exp))
(format stream "~C~:[~;+~]~D"
(etypecase x
(single-float #\f)
(double-float #\d)
(short-float #\s)
(long-float #\L))
plusp exp))))
(defun output-float-infinity (x stream)
(declare (float x) (stream stream))
(cond (*read-eval*
(write-string "#." stream))
(*print-readably*
(error 'print-not-readable :object x))
(t
(write-string "#<" stream)))
(write-string "SB-EXT:" stream)
(write-string (symbol-name (float-format-name x)) stream)
(write-string (if (plusp x) "-POSITIVE-" "-NEGATIVE-")
stream)
(write-string "INFINITY" stream)
(unless *read-eval*
(write-string ">" stream)))
(defun output-float-nan (x 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)))
;;; the function called by OUTPUT-OBJECT to handle floats
(defun output-float (x stream)
(cond
((float-infinity-p x)
(output-float-infinity x stream))
((float-nan-p x)
(output-float-nan x 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
(output-float-aux x stream (float 1/1000 x) (float 10000000 x))))))))
(defun output-float-aux (x stream e-min e-max)
(if (and (>= x e-min) (< x e-max))
;; free format
(multiple-value-bind (str len lpoint tpoint) (flonum-to-string x)
(declare (ignore len))
(when lpoint (write-char #\0 stream))
(write-string str stream)
(when tpoint (write-char #\0 stream))
(print-float-exponent x 0 stream))
;; exponential format
(multiple-value-bind (f ex) (scale-exponent x)
(multiple-value-bind (str len lpoint tpoint)
(flonum-to-string f nil nil 1)
(declare (ignore len))
(when lpoint (write-char #\0 stream))
(write-string str stream)
(when tpoint (write-char #\0 stream))
;; Subtract out scale factor of 1 passed to FLONUM-TO-STRING.
(print-float-exponent x (1- ex) 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.
(defun output-character (char stream)
(if (or *print-escape* *print-readably*)
(let ((name (char-name char)))
(write-string "#\\" stream)
(if name
(quote-string name stream)
(write-char char stream)))
(write-char char stream)))
(defun output-sap (sap stream)
(declare (type system-area-pointer sap))
(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))))))
(defun output-weak-pointer (weak-pointer stream)
(declare (type weak-pointer weak-pointer))
(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))))))
(defun output-code-component (component stream)
(print-unreadable-object (component stream :identity t)
(let ((dinfo (%code-debug-info component)))
(cond ((eq dinfo :bogus-lra)
(write-string "bogus code object" stream))
(t
(write-string "code object" stream)
(when dinfo
(write-char #\space stream)
(output-object (sb!c::debug-info-name dinfo) stream)))))))
(defun output-lra (lra stream)
(print-unreadable-object (lra stream :identity t)
(write-string "return PC object" stream)))
(defun output-fdefn (fdefn stream)
(print-unreadable-object (fdefn stream)
(write-string "FDEFINITION object for " stream)
(output-object (fdefn-name fdefn) stream)))
;;;; functions
;;; Output OBJECT as using PRINT-OBJECT if it's a
;;; FUNCALLABLE-STANDARD-CLASS, or return NIL otherwise.
;;;
;;; The definition here is a simple temporary placeholder. It will be
;;; overwritten by a smarter version (capable of calling generic
;;; PRINT-OBJECT when appropriate) when CLOS is installed.
(defun printed-as-clos-funcallable-standard-class (object stream)
(declare (ignore object stream))
nil)
(defun output-fun (object stream)
(let* ((*print-length* 3) ; in case we have to..
(*print-level* 3) ; ..print an interpreted function definition
;; FIXME: This find-the-function-name idiom ought to be
;; encapsulated in a function somewhere.
(name (case (fun-subtype object)
(#.sb!vm:closure-header-widetag "CLOSURE")
(#.sb!vm:simple-fun-header-widetag (%simple-fun-name object))
(t 'no-name-available)))
(identified-by-name-p (and (symbolp name)
(fboundp name)
(eq (fdefinition name) object))))
(print-unreadable-object (object
stream
:identity (not identified-by-name-p))
(prin1 'function stream)
(unless (eq name 'no-name-available)
(format stream " ~S" name)))))
;;;; catch-all for unknown things
(defun output-random (object stream)
(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-header-widetag
(write-string "value cell " stream)
(output-object (value-cell-ref object) stream))
(t
(write-string "unknown pointer object, widetag=" stream)
(let ((*print-base* 16) (*print-radix* t))
(output-integer widetag stream))))))
((#.sb!vm:fun-pointer-lowtag
#.sb!vm:instance-pointer-lowtag
#.sb!vm:list-pointer-lowtag)
(write-string "unknown pointer object, lowtag=" stream)
(let ((*print-base* 16) (*print-radix* t))
(output-integer lowtag stream)))
(t
(case (widetag-of object)
(#.sb!vm:unbound-marker-widetag
(write-string "unbound marker" stream))
(t
(write-string "unknown immediate object, lowtag=" stream)
(let ((*print-base* 2) (*print-radix* t))
(output-integer lowtag stream))
(write-string ", widetag=" stream)
(let ((*print-base* 16) (*print-radix* t))
(output-integer (widetag-of object) stream)))))))))