-;;;; This file contains definitions and declarations for the
-;;;; EXTENSIONS package which must be available at early cross-compile
-;;;; time, and perhaps also some things which might as well be built
-;;;; at cross-compile time even if they're not strictly needed, since
-;;;; that's harmless. Things which can't be built at cross-compile
-;;;; time (e.g. because they need machinery which only exists inside
-;;;; CMU CL's implementation of the LISP package) do not belong in
-;;;; this file.
+;;;; various extensions (including SB-INT "internal extensions")
+;;;; available both in the cross-compilation host Lisp and in the
+;;;; target SBCL
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;; bound because ANSI specifies it as an exclusive bound.)
(def!type index () `(integer 0 (,sb!xc:array-dimension-limit)))
+;;; like INDEX, but augmented with -1 (useful when using the index
+;;; to count downwards to 0, e.g. LOOP FOR I FROM N DOWNTO 0, with
+;;; an implementation which terminates the loop by testing for the
+;;; index leaving the loop range)
+(def!type index-or-minus-1 () `(integer -1 (,sb!xc:array-dimension-limit)))
+
+;;; A couple of VM-related types that are currently used only on the
+;;; alpha platform. -- CSR, 2002-06-24
+(def!type unsigned-byte-with-a-bite-out (s bite)
+ (cond ((eq s '*) 'integer)
+ ((and (integerp s) (> s 0))
+ (let ((bound (ash 1 s)))
+ `(integer 0 ,(- bound bite 1))))
+ (t
+ (error "Bad size specified for UNSIGNED-BYTE type specifier: ~S." s))))
+
+;;; Motivated by the mips port. -- CSR, 2002-08-22
+(def!type signed-byte-with-a-bite-out (s bite)
+ (cond ((eq s '*) 'integer)
+ ((and (integerp s) (> s 1))
+ (let ((bound (ash 1 (1- s))))
+ `(integer ,(- bound) ,(- bound bite 1))))
+ (t
+ (error "Bad size specified for SIGNED-BYTE type specifier: ~S." s))))
+
+(def!type load/store-index (scale lowtag min-offset
+ &optional (max-offset min-offset))
+ `(integer ,(- (truncate (+ (ash 1 16)
+ (* min-offset sb!vm:n-word-bytes)
+ (- lowtag))
+ scale))
+ ,(truncate (- (+ (1- (ash 1 16)) lowtag)
+ (* max-offset sb!vm:n-word-bytes))
+ scale)))
+
+;;; Similar to FUNCTION, but the result type is "exactly" specified:
+;;; if it is an object type, then the function returns exactly one
+;;; value, if it is a short form of VALUES, then this short form
+;;; specifies the exact number of values.
+(def!type sfunction (args &optional result)
+ (let ((result (cond ((eq result '*) '*)
+ ((or (atom result)
+ (not (eq (car result) 'values)))
+ `(values ,result &optional))
+ ((intersection (cdr result) lambda-list-keywords)
+ result)
+ (t `(values ,@(cdr result) &optional)))))
+ `(function ,args ,result)))
+
+;;; a type specifier
+;;;
+;;; FIXME: The SB!KERNEL:INSTANCE here really means CL:CLASS.
+;;; However, the CL:CLASS type is only defined once PCL is loaded,
+;;; which is before this is evaluated. Once PCL is moved into cold
+;;; init, this might be fixable.
+(def!type type-specifier () '(or list symbol sb!kernel:instance))
+
;;; the default value used for initializing character data. The ANSI
-;;; spec says this is arbitrary. CMU CL used #\NULL, which we avoid
-;;; because it's not in the ANSI table of portable characters.
-(defconstant default-init-char #\space)
+;;; spec says this is arbitrary, so we use the value that falls
+;;; through when we just let the low-level consing code initialize
+;;; all newly-allocated memory to zero.
+;;;
+;;; KLUDGE: It might be nice to use something which is a
+;;; STANDARD-CHAR, both to reduce user surprise a little and, probably
+;;; more significantly, to help SBCL's cross-compiler (which knows how
+;;; to dump STANDARD-CHARs). Unfortunately, the old CMU CL code is
+;;; shot through with implicit assumptions that it's #\NULL, and code
+;;; in several places (notably both DEFUN MAKE-ARRAY and DEFTRANSFORM
+;;; MAKE-ARRAY) would have to be rewritten. -- WHN 2001-10-04
+(eval-when (:compile-toplevel :load-toplevel :execute)
+ ;; an expression we can use to construct a DEFAULT-INIT-CHAR value
+ ;; at load time (so that we don't need to teach the cross-compiler
+ ;; how to represent and dump non-STANDARD-CHARs like #\NULL)
+ (defparameter *default-init-char-form* '(code-char 0)))
;;; CHAR-CODE values for ASCII characters which we care about but
;;; which aren't defined in section "2.1.3 Standard Characters" of the
;;; if so, perhaps implement a DEFTRANSFORM or something to stop it.
;;; (or just find a nicer way of expressing characters portably?) --
;;; WHN 19990713
-(defconstant bell-char-code 7)
-(defconstant tab-char-code 9)
-(defconstant form-feed-char-code 12)
-(defconstant return-char-code 13)
-(defconstant escape-char-code 27)
-(defconstant rubout-char-code 127)
+(def!constant bell-char-code 7)
+(def!constant backspace-char-code 8)
+(def!constant tab-char-code 9)
+(def!constant line-feed-char-code 10)
+(def!constant form-feed-char-code 12)
+(def!constant return-char-code 13)
+(def!constant escape-char-code 27)
+(def!constant rubout-char-code 127)
+\f
+;;;; type-ish predicates
+
+;;; Is X a list containing a cycle?
+(defun cyclic-list-p (x)
+ (and (listp x)
+ (labels ((safe-cddr (x) (if (listp (cdr x)) (cddr x))))
+ (do ((y x (safe-cddr y))
+ (started-p nil t)
+ (z x (cdr z)))
+ ((not (and (consp z) (consp y))) nil)
+ (when (and started-p (eq y z))
+ (return t))))))
+
+;;; Is X a (possibly-improper) list of at least N elements?
+(declaim (ftype (function (t index)) list-of-length-at-least-p))
+(defun list-of-length-at-least-p (x n)
+ (or (zerop n) ; since anything can be considered an improper list of length 0
+ (and (consp x)
+ (list-of-length-at-least-p (cdr x) (1- n)))))
+
+(declaim (inline singleton-p))
+(defun singleton-p (list)
+ (and (consp list)
+ (null (rest list))))
+
+;;; Is X is a positive prime integer?
+(defun positive-primep (x)
+ ;; This happens to be called only from one place in sbcl-0.7.0, and
+ ;; only for fixnums, we can limit it to fixnums for efficiency. (And
+ ;; if we didn't limit it to fixnums, we should use a cleverer
+ ;; algorithm, since this one scales pretty badly for huge X.)
+ (declare (fixnum x))
+ (if (<= x 5)
+ (and (>= x 2) (/= x 4))
+ (and (not (evenp x))
+ (not (zerop (rem x 3)))
+ (do ((q 6)
+ (r 1)
+ (inc 2 (logxor inc 6)) ;; 2,4,2,4...
+ (d 5 (+ d inc)))
+ ((or (= r 0) (> d q)) (/= r 0))
+ (declare (fixnum inc))
+ (multiple-value-setq (q r) (truncate x d))))))
+
+;;; Could this object contain other objects? (This is important to
+;;; the implementation of things like *PRINT-CIRCLE* and the dumper.)
+(defun compound-object-p (x)
+ (or (consp x)
+ (typep x 'instance)
+ (typep x '(array t *))))
+\f
+;;;; the COLLECT macro
+;;;;
+;;;; comment from CMU CL: "the ultimate collection macro..."
+
+;;; helper functions for COLLECT, which become the expanders of the
+;;; MACROLET definitions created by COLLECT
+;;;
+;;; COLLECT-NORMAL-EXPANDER handles normal collection macros.
+;;;
+;;; COLLECT-LIST-EXPANDER handles the list collection case. N-TAIL
+;;; is the pointer to the current tail of the list, or NIL if the list
+;;; is empty.
+(eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute)
+ (defun collect-normal-expander (n-value fun forms)
+ `(progn
+ ,@(mapcar (lambda (form) `(setq ,n-value (,fun ,form ,n-value))) forms)
+ ,n-value))
+ (defun collect-list-expander (n-value n-tail forms)
+ (let ((n-res (gensym)))
+ `(progn
+ ,@(mapcar (lambda (form)
+ `(let ((,n-res (cons ,form nil)))
+ (cond (,n-tail
+ (setf (cdr ,n-tail) ,n-res)
+ (setq ,n-tail ,n-res))
+ (t
+ (setq ,n-tail ,n-res ,n-value ,n-res)))))
+ forms)
+ ,n-value))))
+
+;;; Collect some values somehow. Each of the collections specifies a
+;;; bunch of things which collected during the evaluation of the body
+;;; of the form. The name of the collection is used to define a local
+;;; macro, a la MACROLET. Within the body, this macro will evaluate
+;;; each of its arguments and collect the result, returning the
+;;; current value after the collection is done. The body is evaluated
+;;; as a PROGN; to get the final values when you are done, just call
+;;; the collection macro with no arguments.
+;;;
+;;; INITIAL-VALUE is the value that the collection starts out with,
+;;; which defaults to NIL. FUNCTION is the function which does the
+;;; collection. It is a function which will accept two arguments: the
+;;; value to be collected and the current collection. The result of
+;;; the function is made the new value for the collection. As a
+;;; totally magical special-case, FUNCTION may be COLLECT, which tells
+;;; us to build a list in forward order; this is the default. If an
+;;; INITIAL-VALUE is supplied for COLLECT, the stuff will be RPLACD'd
+;;; onto the end. Note that FUNCTION may be anything that can appear
+;;; in the functional position, including macros and lambdas.
+(defmacro collect (collections &body body)
+ (let ((macros ())
+ (binds ()))
+ (dolist (spec collections)
+ (unless (proper-list-of-length-p spec 1 3)
+ (error "malformed collection specifier: ~S" spec))
+ (let* ((name (first spec))
+ (default (second spec))
+ (kind (or (third spec) 'collect))
+ (n-value (gensym (concatenate 'string
+ (symbol-name name)
+ "-N-VALUE-"))))
+ (push `(,n-value ,default) binds)
+ (if (eq kind 'collect)
+ (let ((n-tail (gensym (concatenate 'string
+ (symbol-name name)
+ "-N-TAIL-"))))
+ (if default
+ (push `(,n-tail (last ,n-value)) binds)
+ (push n-tail binds))
+ (push `(,name (&rest args)
+ (collect-list-expander ',n-value ',n-tail args))
+ macros))
+ (push `(,name (&rest args)
+ (collect-normal-expander ',n-value ',kind args))
+ macros))))
+ `(macrolet ,macros (let* ,(nreverse binds) ,@body))))
+\f
+;;;; some old-fashioned functions. (They're not just for old-fashioned
+;;;; code, they're also used as optimized forms of the corresponding
+;;;; general functions when the compiler can prove that they're
+;;;; equivalent.)
+
+;;; like (MEMBER ITEM LIST :TEST #'EQ)
+(defun memq (item list)
+ #!+sb-doc
+ "Return tail of LIST beginning with first element EQ to ITEM."
+ ;; KLUDGE: These could be and probably should be defined as
+ ;; (MEMBER ITEM LIST :TEST #'EQ)),
+ ;; but when I try to cross-compile that, I get an error from
+ ;; LTN-ANALYZE-KNOWN-CALL, "Recursive known function definition". The
+ ;; comments for that error say it "is probably a botched interpreter stub".
+ ;; Rather than try to figure that out, I just rewrote this function from
+ ;; scratch. -- WHN 19990512
+ (do ((i list (cdr i)))
+ ((null i))
+ (when (eq (car i) item)
+ (return i))))
+
+;;; like (ASSOC ITEM ALIST :TEST #'EQ):
+;;; Return the first pair of ALIST where ITEM is EQ to the key of
+;;; the pair.
+(defun assq (item alist)
+ ;; KLUDGE: CMU CL defined this with
+ ;; (DECLARE (INLINE ASSOC))
+ ;; (ASSOC ITEM ALIST :TEST #'EQ))
+ ;; which is pretty, but which would have required adding awkward
+ ;; build order constraints on SBCL (or figuring out some way to make
+ ;; inline definitions installable at build-the-cross-compiler time,
+ ;; which was too ambitious for now). Rather than mess with that, we
+ ;; just define ASSQ explicitly in terms of more primitive
+ ;; operations:
+ (dolist (pair alist)
+ ;; though it may look more natural to write this as
+ ;; (AND PAIR (EQ (CAR PAIR) ITEM))
+ ;; the temptation to do so should be resisted, as pointed out by PFD
+ ;; sbcl-devel 2003-08-16, as NIL elements are rare in association
+ ;; lists. -- CSR, 2003-08-16
+ (when (and (eq (car pair) item) (not (null pair)))
+ (return pair))))
+
+;;; like (DELETE .. :TEST #'EQ):
+;;; Delete all LIST entries EQ to ITEM (destructively modifying
+;;; LIST), and return the modified LIST.
+(defun delq (item list)
+ (let ((list list))
+ (do ((x list (cdr x))
+ (splice '()))
+ ((endp x) list)
+ (cond ((eq item (car x))
+ (if (null splice)
+ (setq list (cdr x))
+ (rplacd splice (cdr x))))
+ (t (setq splice x)))))) ; Move splice along to include element.
+
+
+;;; like (POSITION .. :TEST #'EQ):
+;;; Return the position of the first element EQ to ITEM.
+(defun posq (item list)
+ (do ((i list (cdr i))
+ (j 0 (1+ j)))
+ ((null i))
+ (when (eq (car i) item)
+ (return j))))
+
+(declaim (inline neq))
+(defun neq (x y)
+ (not (eq x y)))
+
+;;; not really an old-fashioned function, but what the calling
+;;; convention should've been: like NTH, but with the same argument
+;;; order as in all the other dereferencing functions, with the
+;;; collection first and the index second
+(declaim (inline nth-but-with-sane-arg-order))
+(declaim (ftype (function (list index) t) nth-but-with-sane-arg-order))
+(defun nth-but-with-sane-arg-order (list index)
+ (nth index list))
+
+(defun adjust-list (list length initial-element)
+ (let ((old-length (length list)))
+ (cond ((< old-length length)
+ (append list (make-list (- length old-length)
+ :initial-element initial-element)))
+ ((> old-length length)
+ (subseq list 0 length))
+ (t list))))
\f
;;;; miscellaneous iteration extensions
-(defmacro dovector ((elt vector &optional result) &rest forms)
+;;; "the ultimate iteration macro"
+;;;
+;;; note for Schemers: This seems to be identical to Scheme's "named LET".
+(defmacro named-let (name binds &body body)
#!+sb-doc
- "just like DOLIST, but with one-dimensional arrays"
+ (dolist (x binds)
+ (unless (proper-list-of-length-p x 2)
+ (error "malformed NAMED-LET variable spec: ~S" x)))
+ `(labels ((,name ,(mapcar #'first binds) ,@body))
+ (,name ,@(mapcar #'second binds))))
+
+;;; just like DOLIST, but with one-dimensional arrays
+(defmacro dovector ((elt vector &optional result) &rest forms)
(let ((index (gensym))
(length (gensym))
(vec (gensym)))
(let ((,elt (aref ,vec ,index)))
,@forms)))))
+;;; Iterate over the entries in a HASH-TABLE.
(defmacro dohash ((key-var value-var table &optional result) &body body)
- #!+sb-doc
- "DOHASH (Key-Var Value-Var Table [Result]) Declaration* Form*
- Iterate over the entries in a hash-table."
(multiple-value-bind (forms decls) (parse-body body nil)
(let ((gen (gensym))
(n-more (gensym)))
;;; The code for initializing the cache is wrapped in a form with
;;; the specified name. (:INIT-WRAPPER is set to COLD-INIT-FORMS
;;; in type system definitions so that caches will be created
-;;; before top-level forms run.)
+;;; before top level forms run.)
(defmacro define-hash-cache (name args &key hash-function hash-bits default
(init-wrapper 'progn)
(values 1))
(n-cache (gensym)))
(unless (= (length default-values) values)
- (error "The number of default values ~S differs from :VALUES ~D."
+ (error "The number of default values ~S differs from :VALUES ~W."
default values))
(collect ((inlines)
(,n-cache ,var-name))
(declare (type fixnum ,n-index))
,@(sets)
- ,@(mapcar #'(lambda (i val)
- `(setf (svref ,n-cache ,i) ,val))
+ ,@(mapcar (lambda (i val)
+ `(setf (svref ,n-cache ,i) ,val))
(values-indices)
(values-names))
(values)))))
(dotimes (i nargs)
(arg-sets `(setf (svref ,n-cache (+ ,n-index ,i)) nil)))
(arg-sets))
- ,@(mapcar #'(lambda (i val)
- `(setf (svref ,n-cache ,i) ,val))
+ ,@(mapcar (lambda (i val)
+ `(setf (svref ,n-cache ,i) ,val))
(values-indices)
default-values))
(values)))
,@(values-names))
(values ,@(values-names)))
(values ,@(values-names))))))))))))
+
+(defmacro define-cached-synonym
+ (name &optional (original (symbolicate "%" name)))
+ (let ((cached-name (symbolicate "%%" name "-cached")))
+ `(progn
+ (defun-cached (,cached-name :hash-bits 8
+ :hash-function (lambda (x)
+ (logand (sxhash x) #xff)))
+ ((args equal))
+ (apply #',original args))
+ (defun ,name (&rest args)
+ (,cached-name args)))))
+
+;;; FIXME: maybe not the best place
+;;;
+;;; FIXME: think of a better name -- not only does this not have the
+;;; CAR recursion of EQUAL, it also doesn't have the special treatment
+;;; of pathnames, bit-vectors and strings.
+;;;
+;;; KLUDGE: This means that we will no longer cache specifiers of the
+;;; form '(INTEGER (0) 4). This is probably not a disaster.
+;;;
+;;; A helper function for the type system, which is the main user of
+;;; these caches: we must be more conservative than EQUAL for some of
+;;; our equality tests, because MEMBER and friends refer to EQLity.
+;;; So:
+(defun equal-but-no-car-recursion (x y)
+ (cond
+ ((eql x y) t)
+ ((consp x)
+ (and (consp y)
+ (eql (car x) (car y))
+ (equal-but-no-car-recursion (cdr x) (cdr y))))
+ (t nil)))
\f
;;;; package idioms
:format-control "The package ~S has been deleted."
:format-arguments (list maybe-result)))))
\f
-;;;; miscellany
+;;;; various operations on names
;;; Is NAME a legal function name?
-(defun legal-function-name-p (name)
- (or (symbolp name)
- (and (consp name)
- (eq (car name) 'setf)
- (consp (cdr name))
- (symbolp (cadr name))
- (null (cddr name)))))
-
-;;; Given a function name, return the name for the BLOCK which
-;;; encloses its body (e.g. in DEFUN, DEFINE-COMPILER-MACRO, or FLET).
-(declaim (ftype (function ((or symbol cons)) symbol) function-name-block-name))
-(defun function-name-block-name (function-name)
- (cond ((symbolp function-name)
- function-name)
- ((and (consp function-name)
- (= (length function-name) 2)
- (eq (first function-name) 'setf))
- (second function-name))
+(defun legal-fun-name-p (name)
+ (values (valid-function-name-p name)))
+
+;;; Signal an error unless NAME is a legal function name.
+(defun legal-fun-name-or-type-error (name)
+ (unless (legal-fun-name-p name)
+ (error 'simple-type-error
+ :datum name
+ :expected-type '(or symbol list)
+ :format-control "invalid function name: ~S"
+ :format-arguments (list name))))
+
+;;; Given a function name, return the symbol embedded in it.
+;;;
+;;; The ordinary use for this operator (and the motivation for the
+;;; name of this operator) is to convert from a function name to the
+;;; name of the BLOCK which encloses its body.
+;;;
+;;; Occasionally the operator is useful elsewhere, where the operator
+;;; name is less mnemonic. (Maybe it should be changed?)
+(declaim (ftype (function ((or symbol cons)) symbol) fun-name-block-name))
+(defun fun-name-block-name (fun-name)
+ (cond ((symbolp fun-name)
+ fun-name)
+ ((consp fun-name)
+ (multiple-value-bind (legalp block-name)
+ (valid-function-name-p fun-name)
+ (if legalp
+ block-name
+ (error "not legal as a function name: ~S" fun-name))))
(t
- (error "not legal as a function name: ~S" function-name))))
+ (error "not legal as a function name: ~S" fun-name))))
-;;; Is X a (possibly-improper) list of at least N elements?
-(declaim (ftype (function (t index)) list-of-length-at-least-p))
-(defun list-of-length-at-least-p (x n)
- (or (zerop n) ; since anything can be considered an improper list of length 0
- (and (consp x)
- (list-of-length-at-least-p (cdr x) (1- n)))))
+(defun looks-like-name-of-special-var-p (x)
+ (and (symbolp x)
+ (let ((name (symbol-name x)))
+ (and (> (length name) 2) ; to exclude '* and '**
+ (char= #\* (aref name 0))
+ (char= #\* (aref name (1- (length name))))))))
-;;; Return a list of N gensyms. (This is a common suboperation in
-;;; macros and other code-manipulating code.)
-(declaim (ftype (function (index) list) make-gensym-list))
-(defun make-gensym-list (n)
- (loop repeat n collect (gensym)))
-
-;;; ANSI guarantees that some symbols are self-evaluating. This
-;;; function is to be called just before a change which would affect
-;;; that. (We don't absolutely have to call this function before such
-;;; changes, since such changes are given as undefined behavior. In
-;;; particular, we don't if the runtime cost would be annoying. But
-;;; otherwise it's nice to do so.)
-(defun about-to-modify (symbol)
+;;; Some symbols are defined by ANSI to be self-evaluating. Return
+;;; non-NIL for such symbols (and make the non-NIL value a traditional
+;;; message, for use in contexts where the user asks us to change such
+;;; a symbol).
+(defun symbol-self-evaluating-p (symbol)
(declare (type symbol symbol))
(cond ((eq symbol t)
- (error "Veritas aeterna. (can't change T)"))
+ "Veritas aeterna. (can't change T)")
((eq symbol nil)
- (error "Nihil ex nihil. (can't change NIL)"))
+ "Nihil ex nihil. (can't change NIL)")
((keywordp symbol)
- (error "Keyword values can't be changed."))
- ;; (Just because a value is CONSTANTP is not a good enough
- ;; reason to complain here, because we want DEFCONSTANT to
- ;; be able to use this function, and it's legal to DEFCONSTANT
- ;; a constant as long as the new value is EQL to the old
- ;; value.)
- ))
+ "Keyword values can't be changed.")
+ (t
+ nil)))
+
+;;; This function is to be called just before a change which would
+;;; affect the symbol value. (We don't absolutely have to call this
+;;; function before such changes, since such changes are given as
+;;; undefined behavior. In particular, we don't if the runtime cost
+;;; would be annoying. But otherwise it's nice to do so.)
+(defun about-to-modify-symbol-value (symbol)
+ (declare (type symbol symbol))
+ (let ((reason (symbol-self-evaluating-p symbol)))
+ (when reason
+ (error reason)))
+ ;; (Note: Just because a value is CONSTANTP is not a good enough
+ ;; reason to complain here, because we want DEFCONSTANT to be able
+ ;; to use this function, and it's legal to DEFCONSTANT a constant as
+ ;; long as the new value is EQL to the old value.)
+ (values))
+
+
+;;; If COLD-FSET occurs not at top level, just treat it as an ordinary
+;;; assignment instead of doing cold static linking. That way things like
+;;; (FLET ((FROB (X) ..))
+;;; (DEFUN FOO (X Y) (FROB X) ..)
+;;; (DEFUN BAR (Z) (AND (FROB X) ..)))
+;;; can still "work" for cold init: they don't do magical static
+;;; linking the way that true toplevel DEFUNs do, but at least they do
+;;; the linking eventually, so as long as #'FOO and #'BAR aren't
+;;; needed until "cold toplevel forms" have executed, it's OK.
+(defmacro cold-fset (name lambda)
+ (style-warn
+ "~@<COLD-FSET ~S not cross-compiled at top level: demoting to ~
+(SETF FDEFINITION)~:@>"
+ name)
+ ;; We convert the LAMBDA expression to the corresponding NAMED-LAMBDA
+ ;; expression so that the compiler can use NAME in debug names etc.
+ (destructuring-bind (lambda-symbol &rest lambda-rest) lambda
+ (assert (eql lambda-symbol 'lambda)) ; else dunno how to do conversion
+ `(setf (fdefinition ',name)
+ (named-lambda ,name ,@lambda-rest))))
+\f
+;;;; ONCE-ONLY
+;;;;
+;;;; "The macro ONCE-ONLY has been around for a long time on various
+;;;; systems [..] if you can understand how to write and when to use
+;;;; ONCE-ONLY, then you truly understand macro." -- Peter Norvig,
+;;;; _Paradigms of Artificial Intelligence Programming: Case Studies
+;;;; in Common Lisp_, p. 853
+
+;;; ONCE-ONLY is a utility useful in writing source transforms and
+;;; macros. It provides a concise way to wrap a LET around some code
+;;; to ensure that some forms are only evaluated once.
+;;;
+;;; Create a LET* which evaluates each value expression, binding a
+;;; temporary variable to the result, and wrapping the LET* around the
+;;; result of the evaluation of BODY. Within the body, each VAR is
+;;; bound to the corresponding temporary variable.
+(defmacro once-only (specs &body body)
+ (named-let frob ((specs specs)
+ (body body))
+ (if (null specs)
+ `(progn ,@body)
+ (let ((spec (first specs)))
+ ;; FIXME: should just be DESTRUCTURING-BIND of SPEC
+ (unless (proper-list-of-length-p spec 2)
+ (error "malformed ONCE-ONLY binding spec: ~S" spec))
+ (let* ((name (first spec))
+ (exp-temp (gensym (symbol-name name))))
+ `(let ((,exp-temp ,(second spec))
+ (,name (gensym "ONCE-ONLY-")))
+ `(let ((,,name ,,exp-temp))
+ ,,(frob (rest specs) body))))))))
+\f
+;;;; various error-checking utilities
+
+;;; This function can be used as the default value for keyword
+;;; arguments that must be always be supplied. Since it is known by
+;;; the compiler to never return, it will avoid any compile-time type
+;;; warnings that would result from a default value inconsistent with
+;;; the declared type. When this function is called, it signals an
+;;; error indicating that a required &KEY argument was not supplied.
+;;; This function is also useful for DEFSTRUCT slot defaults
+;;; corresponding to required arguments.
+(declaim (ftype (function () nil) missing-arg))
+(defun missing-arg ()
+ #!+sb-doc
+ (/show0 "entering MISSING-ARG")
+ (error "A required &KEY or &OPTIONAL argument was not supplied."))
+
+;;; like CL:ASSERT and CL:CHECK-TYPE, but lighter-weight
+;;;
+;;; (As of sbcl-0.6.11.20, we were using some 400 calls to CL:ASSERT.
+;;; The CL:ASSERT restarts and whatnot expand into a significant
+;;; amount of code when you multiply them by 400, so replacing them
+;;; with this should reduce the size of the system by enough to be
+;;; worthwhile. ENFORCE-TYPE is much less common, but might still be
+;;; worthwhile, and since I don't really like CERROR stuff deep in the
+;;; guts of complex systems anyway, I replaced it too.)
+(defmacro aver (expr)
+ `(unless ,expr
+ (%failed-aver ,(format nil "~A" expr))))
+
+(defun %failed-aver (expr-as-string)
+ (bug "~@<failed AVER: ~2I~_~S~:>" expr-as-string))
+
+;;; We need a definition of BUG here for the host compiler to be able
+;;; to deal with BUGs in sbcl. This should never affect an end-user,
+;;; who will pick up the definition that signals a CONDITION of
+;;; condition-class BUG; however, this is not defined on the host
+;;; lisp, but for the target. SBCL developers sometimes trigger BUGs
+;;; in their efforts, and it is useful to get the details of the BUG
+;;; rather than an undefined function error. - CSR, 2002-04-12
+#+sb-xc-host
+(defun bug (format-control &rest format-arguments)
+ (error 'simple-error
+ :format-control "~@< ~? ~:@_~?~:>"
+ :format-arguments `(,format-control
+ ,format-arguments
+ "~@<If you see this and are an SBCL ~
+developer, then it is probable that you have made a change to the ~
+system that has broken the ability for SBCL to compile, usually by ~
+removing an assumed invariant of the system, but sometimes by making ~
+an averrance that is violated (check your code!). If you are a user, ~
+please submit a bug report to the developers' mailing list, details of ~
+which can be found at <http://sbcl.sourceforge.net/>.~:@>"
+ ())))
+(defmacro enforce-type (value type)
+ (once-only ((value value))
+ `(unless (typep ,value ',type)
+ (%failed-enforce-type ,value ',type))))
+
+(defun %failed-enforce-type (value type)
+ (error 'simple-type-error ; maybe should be TYPE-BUG, subclass of BUG?
+ :value value
+ :expected-type type
+ :format-control "~@<~S ~_is not a ~_~S~:>"
+ :format-arguments (list value type)))
+\f
;;; Return a function like FUN, but expecting its (two) arguments in
;;; the opposite order that FUN does.
(declaim (inline swapped-args-fun))
(lambda (x y)
(funcall fun y x)))
-;;; like CL:ASSERT, but lighter-weight
-;;;
-;;; (As of sbcl-0.6.11.20, we were using some 400 calls to CL:ASSERT
-;;; in SBCL. The CL:ASSERT restarts and whatnot expand into a
-;;; significant amount of code when you multiply them by 400, so
-;;; replacing them with this should reduce the size of the system
-;;; by enough to be worthwhile.)
-(defmacro aver (expr)
- `(unless ,expr
- (%failed-aver ,(let ((*package* (find-package :keyword)))
- (format nil "~S" expr)))))
-(defun %failed-aver (expr-as-string)
- (error "~@<failed AVER: ~2I~_~S~:>" expr-as-string))
-
;;; Return the numeric value of a type bound, i.e. an interval bound
;;; more or less in the format of bounds in ANSI's type specifiers,
;;; where a bare numeric value is a closed bound and a list of a
(def-constantly-fun constantly-t t)
(def-constantly-fun constantly-nil nil)
(def-constantly-fun constantly-0 0))
+
+;;; If X is an atom, see whether it is present in *FEATURES*. Also
+;;; handle arbitrary combinations of atoms using NOT, AND, OR.
+(defun featurep (x)
+ (if (consp x)
+ (case (car x)
+ ((:not not)
+ (if (cddr x)
+ (error "too many subexpressions in feature expression: ~S" x)
+ (not (featurep (cadr x)))))
+ ((:and and) (every #'featurep (cdr x)))
+ ((:or or) (some #'featurep (cdr x)))
+ (t
+ (error "unknown operator in feature expression: ~S." x)))
+ (not (null (memq x *features*)))))
+
+;;; Given a list of keyword substitutions `(,OLD ,NEW), and a
+;;; &KEY-argument-list-style list of alternating keywords and
+;;; arbitrary values, return a new &KEY-argument-list-style list with
+;;; all substitutions applied to it.
+;;;
+;;; Note: If efficiency mattered, we could do less consing. (But if
+;;; efficiency mattered, why would we be using &KEY arguments at
+;;; all, much less renaming &KEY arguments?)
+;;;
+;;; KLUDGE: It would probably be good to get rid of this. -- WHN 19991201
+(defun rename-key-args (rename-list key-args)
+ (declare (type list rename-list key-args))
+ ;; Walk through RENAME-LIST modifying RESULT as per each element in
+ ;; RENAME-LIST.
+ (do ((result (copy-list key-args))) ; may be modified below
+ ((null rename-list) result)
+ (destructuring-bind (old new) (pop rename-list)
+ ;; ANSI says &KEY arg names aren't necessarily KEYWORDs.
+ (declare (type symbol old new))
+ ;; Walk through RESULT renaming any OLD key argument to NEW.
+ (do ((in-result result (cddr in-result)))
+ ((null in-result))
+ (declare (type list in-result))
+ (when (eq (car in-result) old)
+ (setf (car in-result) new))))))
+
+;;; ANSI Common Lisp's READ-SEQUENCE function, unlike most of the
+;;; other ANSI input functions, is defined to communicate end of file
+;;; status with its return value, not by signalling. That is not the
+;;; behavior that we usually want. This function is a wrapper which
+;;; restores the behavior that we usually want, causing READ-SEQUENCE
+;;; to communicate end-of-file status by signalling.
+(defun read-sequence-or-die (sequence stream &key start end)
+ ;; implementation using READ-SEQUENCE
+ #-no-ansi-read-sequence
+ (let ((read-end (read-sequence sequence
+ stream
+ :start start
+ :end end)))
+ (unless (= read-end end)
+ (error 'end-of-file :stream stream))
+ (values))
+ ;; workaround for broken READ-SEQUENCE
+ #+no-ansi-read-sequence
+ (progn
+ (aver (<= start end))
+ (let ((etype (stream-element-type stream)))
+ (cond ((equal etype '(unsigned-byte 8))
+ (do ((i start (1+ i)))
+ ((>= i end)
+ (values))
+ (setf (aref sequence i)
+ (read-byte stream))))
+ (t (error "unsupported element type ~S" etype))))))
\f
;;;; utilities for two-VALUES predicates
+(defmacro not/type (x)
+ (let ((val (gensym "VAL"))
+ (win (gensym "WIN")))
+ `(multiple-value-bind (,val ,win)
+ ,x
+ (if ,win
+ (values (not ,val) t)
+ (values nil nil)))))
+
+(defmacro and/type (x y)
+ `(multiple-value-bind (val1 win1) ,x
+ (if (and (not val1) win1)
+ (values nil t)
+ (multiple-value-bind (val2 win2) ,y
+ (if (and val1 val2)
+ (values t t)
+ (values nil (and win2 (not val2))))))))
+
;;; sort of like ANY and EVERY, except:
;;; * We handle two-VALUES predicate functions, as SUBTYPEP does.
;;; (And if the result is uncertain, then we return (VALUES NIL NIL),
;;;
;;; The structure being printed is bound to STRUCTURE and the stream
;;; is bound to STREAM.
-(defmacro defprinter ((name &key (conc-name (concatenate 'simple-string
- (symbol-name name)
- "-")))
+(defmacro defprinter ((name
+ &key
+ (conc-name (concatenate 'simple-string
+ (symbol-name name)
+ "-"))
+ identity)
&rest slot-descs)
(let ((first? t)
maybe-print-space
(t
(error "bad option: ~S" (first option)))))))))))
`(def!method print-object ((structure ,name) ,stream)
- ;; FIXME: should probably be byte-compiled
(pprint-logical-block (,stream nil)
- (print-unreadable-object (structure ,stream :type t)
+ (print-unreadable-object (structure
+ ,stream
+ :type t
+ :identity ,identity)
,@(nreverse reversed-prints))))))
\f
-#|
-;;; REMOVEME when done testing byte cross-compiler
-(defun byte-compiled-foo (x y)
- (declare (optimize (speed 0) (debug 1)))
- (if x
- x
- (cons y y)))
-|#
+;;;; etc.
+
+;;; Given a pathname, return a corresponding physical pathname.
+(defun physicalize-pathname (possibly-logical-pathname)
+ (if (typep possibly-logical-pathname 'logical-pathname)
+ (translate-logical-pathname possibly-logical-pathname)
+ possibly-logical-pathname))
+
+(defun deprecation-warning (bad-name &optional good-name)
+ (warn "using deprecated ~S~@[, should use ~S instead~]"
+ bad-name
+ good-name))
+
+;;; Anaphoric macros
+(defmacro awhen (test &body body)
+ `(let ((it ,test))
+ (when it ,@body)))
+
+(defmacro acond (&rest clauses)
+ (if (null clauses)
+ `()
+ (destructuring-bind ((test &body body) &rest rest) clauses
+ (once-only ((test test))
+ `(if ,test
+ (let ((it ,test)) (declare (ignorable it)),@body)
+ (acond ,@rest))))))
+
+;;; (binding* ({(name initial-value [flag])}*) body)
+;;; FLAG may be NIL or :EXIT-IF-NULL
+;;;
+;;; This form unites LET*, MULTIPLE-VALUE-BIND and AWHEN.
+(defmacro binding* ((&rest bindings) &body body)
+ (let ((bindings (reverse bindings)))
+ (loop with form = `(progn ,@body)
+ for binding in bindings
+ do (destructuring-bind (names initial-value &optional flag)
+ binding
+ (multiple-value-bind (names declarations)
+ (etypecase names
+ (null
+ (let ((name (gensym)))
+ (values (list name) `((declare (ignorable ,name))))))
+ (symbol
+ (values (list names) nil))
+ (list
+ (values names nil)))
+ (setq form `(multiple-value-bind ,names
+ ,initial-value
+ ,@declarations
+ ,(ecase flag
+ ((nil) form)
+ ((:exit-if-null)
+ `(when ,(first names) ,form)))))))
+ finally (return form))))
+\f
+;;; Delayed evaluation
+(defmacro delay (form)
+ `(cons nil (lambda () ,form)))
+
+(defun force (promise)
+ (cond ((not (consp promise)) promise)
+ ((car promise) (cdr promise))
+ (t (setf (car promise) t
+ (cdr promise) (funcall (cdr promise))))))
+
+(defun promise-ready-p (promise)
+ (or (not (consp promise))
+ (car promise)))