3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
12 (in-package "SB!IMPL")
14 ;;; general case of EVAL (except in that it can't handle toplevel
15 ;;; EVAL-WHEN magic properly): Delegate to #'COMPILE.
16 (defun %eval (expr lexenv)
17 (funcall (sb!c:compile-in-lexenv
18 (gensym "EVAL-TMPFUN-")
21 ;; The user can reasonably expect that the
22 ;; interpreter will be safe.
23 (declare (optimize (safety 3)))
25 ;; It's also good if the interpreter doesn't
26 ;; spend too long thinking about each input
27 ;; form, since if the user'd wanted the
28 ;; tradeoff to favor quality of compiled code
29 ;; over compilation speed, he'd've explicitly
30 ;; asked for compilation.
31 (declare (optimize (compilation-speed 2)))
33 ;; Other properties are relatively unimportant.
34 (declare (optimize (speed 1) (debug 1) (space 1)))
39 ;;; Handle PROGN and implicit PROGN.
40 (defun eval-progn-body (progn-body lexenv)
41 (unless (list-with-length-p progn-body)
42 (let ((*print-circle* t))
43 (error 'simple-program-error
45 "~@<not a proper list in PROGN or implicit PROGN: ~2I~_~S~:>"
46 :format-arguments (list progn-body))))
48 ;; * We can't just use (MAP NIL #'EVAL PROGN-BODY) here, because we
49 ;; need to take care to return all the values of the final EVAL.
50 ;; * It's left as an exercise to the reader to verify that this
51 ;; gives the right result when PROGN-BODY is NIL, because
52 ;; (FIRST NIL) = (REST NIL) = NIL.
53 (do* ((i progn-body rest-i)
54 (rest-i (rest i) (rest i)))
56 (if rest-i ; if not last element of list
57 (eval-in-lexenv (first i) lexenv)
58 (return (eval-in-lexenv (first i) lexenv)))))
60 (defun eval (original-exp)
62 "Evaluate the argument in a null lexical environment, returning the
64 (eval-in-lexenv original-exp (make-null-lexenv)))
66 ;;; Pick off a few easy cases, and the various top level EVAL-WHEN
67 ;;; magical cases, and call %EVAL for the rest.
68 (defun eval-in-lexenv (original-exp lexenv)
69 (declare (optimize (safety 1)))
70 ;; (aver (lexenv-simple-p lexenv))
71 (let ((exp (macroexpand original-exp lexenv)))
74 (ecase (info :variable :kind exp)
76 (values (info :variable :constant-value exp)))
79 ;; FIXME: This special case here is a symptom of non-ANSI
80 ;; weirdness in SBCL's ALIEN implementation, which could
81 ;; cause problems for e.g. code walkers. It'd probably be
82 ;; good to ANSIfy it by making alien variable accessors into
83 ;; ordinary forms, e.g. (SB-UNIX:ENV) and (SETF SB-UNIX:ENV),
84 ;; instead of magical symbols, e.g. plain SB-UNIX:ENV. Then
85 ;; if the old magical-symbol syntax is to be retained for
86 ;; compatibility, it can be implemented with
87 ;; DEFINE-SYMBOL-MACRO, keeping the code walkers happy.
89 (%eval original-exp lexenv))))
91 (let ((name (first exp))
92 (n-args (1- (length exp))))
96 (error "wrong number of args to FUNCTION:~% ~S" exp))
97 (let ((name (second exp)))
98 (if (and (or (atom name)
100 (eq (car name) 'setf)))
101 (not (consp (let ((sb!c:*lexenv* lexenv))
102 (sb!c:lexenv-find name funs)))))
104 (%eval original-exp lexenv))))
107 (error "wrong number of args to QUOTE:~% ~S" exp))
110 (unless (evenp n-args)
111 (error "odd number of args to SETQ:~% ~S" exp))
112 (unless (zerop n-args)
113 (do ((name (cdr exp) (cddr name)))
115 (do ((args (cdr exp) (cddr args)))
117 ;; We duplicate the call to SET so that the
118 ;; correct value gets returned.
119 (set (first args) (eval (second args))))
120 (set (first args) (eval (second args)))))
121 (let ((symbol (first name)))
122 (case (info :variable :kind symbol)
123 ;; FIXME: I took out the *TOPLEVEL-AUTO-DECLARE*
124 ;; test here, and removed the *TOPLEVEL-AUTO-DECLARE*
125 ;; variable; the code should now act as though that
126 ;; variable is NIL. This should be tested..
128 (t (return (%eval original-exp lexenv))))))))
130 (eval-progn-body (rest exp) lexenv))
132 ;; FIXME: DESTRUCTURING-BIND returns ARG-COUNT-ERROR
133 ;; instead of PROGRAM-ERROR when there's something wrong
134 ;; with the syntax here (e.g. missing SITUATIONS). This
135 ;; could be fixed by hand-crafting clauses to catch and
136 ;; report each possibility, but it would probably be
137 ;; cleaner to write a new macro
138 ;; DESTRUCTURING-BIND-PROGRAM-SYNTAX which does
139 ;; DESTRUCTURING-BIND and promotes any mismatch to
140 ;; PROGRAM-ERROR, then to use it here and in (probably
141 ;; dozens of) other places where the same problem arises.
142 (destructuring-bind (eval-when situations &rest body) exp
143 (declare (ignore eval-when))
144 (multiple-value-bind (ct lt e)
145 (sb!c:parse-eval-when-situations situations)
146 ;; CLHS 3.8 - Special Operator EVAL-WHEN: The use of
147 ;; the situation :EXECUTE (or EVAL) controls whether
148 ;; evaluation occurs for other EVAL-WHEN forms; that
149 ;; is, those that are not top level forms, or those in
150 ;; code processed by EVAL or COMPILE. If the :EXECUTE
151 ;; situation is specified in such a form, then the
152 ;; body forms are processed as an implicit PROGN;
153 ;; otherwise, the EVAL-WHEN form returns NIL.
154 (declare (ignore ct lt))
156 (eval-progn-body body lexenv)))))
158 (if (and (symbolp name)
159 (eq (info :function :kind name) :function))
161 (dolist (arg (rest exp))
163 (apply (symbol-function name) (args)))
164 (%eval original-exp lexenv))))))
168 ;;; miscellaneous full function definitions of things which are
169 ;;; ordinarily handled magically by the compiler
171 (defun apply (function arg &rest arguments)
173 "Apply FUNCTION to a list of arguments produced by evaluating ARGUMENTS in
174 the manner of LIST*. That is, a list is made of the values of all but the
175 last argument, appended to the value of the last argument, which must be a
177 (cond ((atom arguments)
178 (apply function arg))
179 ((atom (cdr arguments))
180 (apply function (cons arg (car arguments))))
181 (t (do* ((a1 arguments a2)
182 (a2 (cdr arguments) (cdr a2)))
185 (apply function (cons arg arguments)))))))
187 (defun funcall (function &rest arguments)
189 "Call FUNCTION with the given ARGUMENTS."
190 (apply function arguments))
192 (defun values (&rest values)
194 "Return all arguments, in order, as values."
195 (values-list values))
197 (defun values-list (list)
199 "Return all of the elements of LIST, in order, as values."