+;;;; EVAL and friends
+
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
-(in-package "SB!EVAL")
+(in-package "SB!IMPL")
+
+;;; general case of EVAL (except in that it can't handle toplevel
+;;; EVAL-WHEN magic properly): Delegate to #'COMPILE.
+(defun %eval (expr lexenv)
+ (funcall (sb!c:compile-in-lexenv
+ (gensym "EVAL-TMPFUN-")
+ `(lambda ()
+ ,expr)
+ lexenv)))
+
+;;; Handle PROGN and implicit PROGN.
+(defun eval-progn-body (progn-body lexenv)
+ (unless (list-with-length-p progn-body)
+ (let ((*print-circle* t))
+ (error 'simple-program-error
+ :format-control
+ "~@<not a proper list in PROGN or implicit PROGN: ~2I~_~S~:>"
+ :format-arguments (list progn-body))))
+ ;; Note:
+ ;; * We can't just use (MAP NIL #'EVAL PROGN-BODY) here, because we
+ ;; need to take care to return all the values of the final EVAL.
+ ;; * It's left as an exercise to the reader to verify that this
+ ;; gives the right result when PROGN-BODY is NIL, because
+ ;; (FIRST NIL) = (REST NIL) = NIL.
+ (do* ((i progn-body rest-i)
+ (rest-i (rest i) (rest i)))
+ (nil)
+ (if rest-i ; if not last element of list
+ (eval-in-lexenv (first i) lexenv)
+ (return (eval-in-lexenv (first i) lexenv)))))
+
+(defun eval (original-exp)
+ #!+sb-doc
+ "Evaluate the argument in a null lexical environment, returning the
+ result or results."
+ (eval-in-lexenv original-exp (make-null-lexenv)))
+
+;;; Pick off a few easy cases, and the various top level EVAL-WHEN
+;;; magical cases, and call %EVAL for the rest.
+(defun eval-in-lexenv (original-exp lexenv)
+ (declare (optimize (safety 1)))
+ ;; (aver (lexenv-simple-p lexenv))
+ (let ((exp (macroexpand original-exp lexenv)))
+ (typecase exp
+ (symbol
+ (ecase (info :variable :kind exp)
+ (:constant
+ (values (info :variable :constant-value exp)))
+ ((:special :global)
+ (symbol-value exp))
+ ;; FIXME: This special case here is a symptom of non-ANSI
+ ;; weirdness in SBCL's ALIEN implementation, which could
+ ;; cause problems for e.g. code walkers. It'd probably be
+ ;; good to ANSIfy it by making alien variable accessors into
+ ;; ordinary forms, e.g. (SB-UNIX:ENV) and (SETF SB-UNIX:ENV),
+ ;; instead of magical symbols, e.g. plain SB-UNIX:ENV. Then
+ ;; if the old magical-symbol syntax is to be retained for
+ ;; compatibility, it can be implemented with
+ ;; DEFINE-SYMBOL-MACRO, keeping the code walkers happy.
+ (:alien
+ (%eval original-exp lexenv))))
+ (list
+ (let ((name (first exp))
+ (n-args (1- (length exp))))
+ (case name
+ ((function)
+ (unless (= n-args 1)
+ (error "wrong number of args to FUNCTION:~% ~S" exp))
+ (let ((name (second exp)))
+ (if (and (legal-fun-name-p name)
+ (not (consp (let ((sb!c:*lexenv* lexenv))
+ (sb!c:lexenv-find name funs)))))
+ (fdefinition name)
+ (%eval original-exp lexenv))))
+ ((quote)
+ (unless (= n-args 1)
+ (error "wrong number of args to QUOTE:~% ~S" exp))
+ (second exp))
+ (setq
+ (unless (evenp n-args)
+ (error "odd number of args to SETQ:~% ~S" exp))
+ (unless (zerop n-args)
+ (do ((name (cdr exp) (cddr name)))
+ ((null name)
+ (do ((args (cdr exp) (cddr args)))
+ ((null (cddr args))
+ ;; We duplicate the call to SET so that the
+ ;; correct value gets returned.
+ (set (first args) (eval (second args))))
+ (set (first args) (eval (second args)))))
+ (let ((symbol (first name)))
+ (case (info :variable :kind symbol)
+ ;; FIXME: I took out the *TOPLEVEL-AUTO-DECLARE*
+ ;; test here, and removed the *TOPLEVEL-AUTO-DECLARE*
+ ;; variable; the code should now act as though that
+ ;; variable is NIL. This should be tested..
+ (:special)
+ (t (return (%eval original-exp lexenv))))))))
+ ((progn)
+ (eval-progn-body (rest exp) lexenv))
+ ((eval-when)
+ ;; FIXME: DESTRUCTURING-BIND returns ARG-COUNT-ERROR
+ ;; instead of PROGRAM-ERROR when there's something wrong
+ ;; with the syntax here (e.g. missing SITUATIONS). This
+ ;; could be fixed by hand-crafting clauses to catch and
+ ;; report each possibility, but it would probably be
+ ;; cleaner to write a new macro
+ ;; DESTRUCTURING-BIND-PROGRAM-SYNTAX which does
+ ;; DESTRUCTURING-BIND and promotes any mismatch to
+ ;; PROGRAM-ERROR, then to use it here and in (probably
+ ;; dozens of) other places where the same problem arises.
+ (destructuring-bind (eval-when situations &rest body) exp
+ (declare (ignore eval-when))
+ (multiple-value-bind (ct lt e)
+ (sb!c:parse-eval-when-situations situations)
+ ;; CLHS 3.8 - Special Operator EVAL-WHEN: The use of
+ ;; the situation :EXECUTE (or EVAL) controls whether
+ ;; evaluation occurs for other EVAL-WHEN forms; that
+ ;; is, those that are not top level forms, or those in
+ ;; code processed by EVAL or COMPILE. If the :EXECUTE
+ ;; situation is specified in such a form, then the
+ ;; body forms are processed as an implicit PROGN;
+ ;; otherwise, the EVAL-WHEN form returns NIL.
+ (declare (ignore ct lt))
+ (when e
+ (eval-progn-body body lexenv)))))
+ ((locally)
+ (multiple-value-bind (body decls) (parse-body (rest exp) nil)
+ (let ((lexenv
+ ;; KLUDGE: Uh, yeah. I'm not anticipating
+ ;; winning any prizes for this code, which was
+ ;; written on a "let's get it to work" basis.
+ ;; These seem to be the variables that need
+ ;; bindings for PROCESS-DECLS to work
+ ;; (*FREE-FUNS* and *FREE-VARS* so that
+ ;; references to free functions and variables in
+ ;; the declarations can be noted;
+ ;; *UNDEFINED-WARNINGS* so that warnings about
+ ;; undefined things can be accumulated [and then
+ ;; thrown away, as it happens]). -- CSR, 2002-10-24
+ (let ((sb!c:*lexenv* lexenv)
+ (sb!c::*free-funs* (make-hash-table :test 'equal))
+ (sb!c::*free-vars* (make-hash-table :test 'eq))
+ (sb!c::*undefined-warnings* nil))
+ (sb!c::process-decls decls
+ nil nil
+ (sb!c::make-continuation)
+ lexenv))))
+ (eval-progn-body body lexenv))))
+ ((macrolet)
+ (destructuring-bind (definitions &rest body)
+ (rest exp)
+ ;; FIXME: shared code with FUNCALL-IN-FOOMACROLET-LEXENV
+ (declare (type list definitions))
+ (unless (= (length definitions)
+ (length (remove-duplicates definitions :key #'first)))
+ (style-warn "duplicate definitions in ~S" definitions))
+ (let ((lexenv
+ (sb!c::make-lexenv
+ :default lexenv
+ :funs (mapcar
+ (sb!c::macrolet-definitionize-fun
+ :eval
+ ;; I'm not sure that this is the correct
+ ;; LEXENV to be compiling local macros
+ ;; in...
+ lexenv)
+ definitions))))
+ (eval-in-lexenv `(locally ,@body) lexenv))))
+ ((symbol-macrolet)
+ (destructuring-bind (definitions &rest body)
+ (rest exp)
+ ;; FIXME: shared code with FUNCALL-IN-FOOMACROLET-LEXENV
+ (declare (type list definitions))
+ (unless (= (length definitions)
+ (length (remove-duplicates definitions :key #'first)))
+ (style-warn "duplicate definitions in ~S" definitions))
+ (let ((lexenv
+ (sb!c::make-lexenv
+ :default lexenv
+ :vars (mapcar
+ (sb!c::symbol-macrolet-definitionize-fun
+ :eval)
+ definitions))))
+ (eval-in-lexenv `(locally ,@body) lexenv))))
+ (t
+ (if (and (symbolp name)
+ (eq (info :function :kind name) :function))
+ (collect ((args))
+ (dolist (arg (rest exp))
+ (args (eval-in-lexenv arg lexenv)))
+ (apply (symbol-function name) (args)))
+ (%eval exp lexenv))))))
+ (t
+ exp))))
+\f
+;;; miscellaneous full function definitions of things which are
+;;; ordinarily handled magically by the compiler
+
+(defun apply (function arg &rest arguments)
+ #!+sb-doc
+ "Apply FUNCTION to a list of arguments produced by evaluating ARGUMENTS in
+ the manner of LIST*. That is, a list is made of the values of all but the
+ last argument, appended to the value of the last argument, which must be a
+ list."
+ (cond ((atom arguments)
+ (apply function arg))
+ ((atom (cdr arguments))
+ (apply function (cons arg (car arguments))))
+ (t (do* ((a1 arguments a2)
+ (a2 (cdr arguments) (cdr a2)))
+ ((atom (cdr a2))
+ (rplacd a1 (car a2))
+ (apply function (cons arg arguments)))))))
+
+(defun funcall (function &rest arguments)
+ #!+sb-doc
+ "Call FUNCTION with the given ARGUMENTS."
+ (apply function arguments))
-(file-comment
- "$Header$")
+(defun values (&rest values)
+ #!+sb-doc
+ "Return all arguments, in order, as values."
+ (values-list values))
-;;; This flag is used by EVAL-WHEN to keep track of when code has already been
-;;; evaluated so that it can avoid multiple evaluation of nested EVAL-WHEN
-;;; (COMPILE)s.
-(defvar *already-evaled-this* nil)
+(defun values-list (list)
+ #!+sb-doc
+ "Return all of the elements of LIST, in order, as values."
+ (values-list list))
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