(with-default-error-location (,floc)
,@body))))))
- (flet ((dispatch (name args &rest spec)
- (oplambda
- (let ((args (mapcar (compose #'funcall #'cons) args)))
- (aif (find-if (lambda (item)
- (every (lambda (type arg)
- (eql type (car arg)))
- (cddr item) args))
- spec)
- (values (car it) (apply (cadr it) (mapcar #'cdr args)))
- (error "Type mismatch: operator `~A' applied to ~
- types ~{~(~A~)~#[~; and ~;, ~]~}"
- name (mapcar #'car args)))))))
+ (labels ((want (type thunk)
+ ;; Evaluate THUNK and convert its result to the given TYPE.
+ (multiple-value-bind (ty val) (funcall thunk)
+ (coerce-property-value val ty type)))
+
+ (int-unop (intop x)
+ ;; Evaluate X to an integer, and apply INTOP to the result,
+ ;; giving another integer.
+ (oplambda (values :int (funcall intop (want :int x)))))
+
+ (int-binop (intop x y)
+ ;; Evaluate X and Y to integers, and apply INTOP to the
+ ;; results, giving another integer.
+ (oplambda
+ (values :int (funcall intop (want :int x) (want :int y)))))
+
+ (compareop (intop strop x y)
+ ;; Evaluate X and Y. If they're integers, then apply INTOP to
+ ;; them; if they're strings, apply STROP. The result is a
+ ;; boolean.
+ (oplambda
+ (multiple-value-bind (xty xval) (funcall x)
+ (case xty
+ (:int
+ (values :boolean
+ (funcall intop xval (want :int y))))
+ ((:id :string :symbol)
+ (values :boolean
+ (funcall strop
+ (coerce-property-value xval xty :id)
+ (want :id y))))
+ (t
+ (error "Can't compare objects of type ~(~A~)" xty)))))))
(with-parser-context (token-scanner-context :scanner scanner)
(when-parse ()
;; Parse the expression, producing a thunk.
(expr (:nestedp nestedp)
+
(lisp (case (token-type scanner)
+
((:int :id :char :string)
+ ;; A simple literal.
(let ((type (token-type scanner))
(value (token-value scanner)))
(scanner-step scanner)
(values (lambda () (values type value)) t t)))
+
(#\?
+ ;; A Lisp s-expression. Catch and report reader-
+ ;; errors (though the main parser will probably
+ ;; end up /very/ confused); delay evaluation for
+ ;; later.
(handler-case
(let* ((stream (make-scanner-stream scanner))
(sexp (read stream t)))
"Lisp `read' error: ~A"
cond)
(values #'continue t t))))
+
(#\{
+ ;; A code fragment.
(let ((fragment (parse-delimited-fragment scanner
#\{ #\})))
(values (lambda () (values :fragment fragment))
t t)))
+
(#\<
+ ;; A C type.
(parse (seq (#\<
(ds (parse-c-type scanner))
(dc (parse-declarator
#\>)
(values (lambda () (values :type (car dc)))
t t))))
+
(t
+ ;; Anything else is an error.
(values (list :int :id :char :string #\? #\{ #\<)
nil nil))))
- ((:op #\* binop "*" (x y 7)
- (dispatch "*" (list x y) (list :int #'* :int :int)))
- (:op #\/ binop "/" (x y 7)
- (dispatch "/" (list x y)
- (list :int
- (lambda (x y)
- (cond ((zerop y)
- (cerror*
- "Division by zero")
- (cons :invalid nil))
- (t
- (floor x y))))
- :int :int)))
- (:op #\+ binop "+" (x y 5)
- (dispatch "+" (list x y) (list :int #'+ :int :int)))
- (:op #\- binop "-" (x y 5)
- (dispatch "-" (list x y) (list :int #'- :int :int))))
-
- ((:op #\+ preop "+" (x 9)
- (dispatch "+" (list x) (list :int #'+ :int)))
- (:op #\- preop "-" (x 9)
- (dispatch "-" (list x) (list :int #'- :int)))
+ ;; Binary operators.
+ ((:op #\* binop "*" (x y 70) (int-binop #'* x y))
+ (:op #\/ binop "/" (x y 70)
+ (oplambda
+ (let ((x (want :int x)) (y (want :int y)))
+ (when (zerop y) (error "Division by zero"))
+ (values :int (floor x y)))))
+ (:op #\+ binop "+" (x y 60) (int-binop #'+ x y))
+ (:op #\- binop "-" (x y 60) (int-binop #'- x y))
+ (:op :shl binop "<<" (x y 50) (int-binop #'ash x y))
+ (:op :shr binop ">>" (x y 50)
+ (int-binop (lambda (x y) (ash x (- y))) x y))
+ (:op #\< binop "<" (x y 45)
+ (compareop #'< #'string< x y))
+ (:op :le binop "<=" (x y 45)
+ (compareop #'<= #'string<= x y))
+ (:op :ge binop ">=" (x y 45)
+ (compareop #'>= #'string>= x y))
+ (:op #\> binop ">" (x y 45)
+ (compareop #'> #'string> x y))
+ (:op :eq binop "==" (x y 40)
+ (compareop #'= #'string= x y))
+ (:op :ne binop "!=" (x y 40)
+ (compareop #'/= #'string/= x y))
+ (:op #\& binop "&" (x y 37) (int-binop #'logand x y))
+ (:op #\^ binop "^" (x y 35) (int-binop #'logxor x y))
+ (:op #\| binop "|" (x y 32) (int-binop #'logior x y))
+ (:op :and binop "&&" (x y 27)
+ (oplambda (if (want :boolean x) (funcall y)
+ (values :boolean nil))))
+ (:op :or binop "||" (x y 22)
+ (oplambda
+ (multiple-value-bind (xty xval) (funcall x)
+ (if (coerce-property-value xval xty :boolean)
+ (values xty xval)
+ (funcall y))))))
+
+ ;; Prefix operators.
+ ((:op #\~ preop "~" (x 90) (int-unop #'lognot x))
+ (:op #\! preop "!" (x 90)
+ (oplambda
+ (values :boolean
+ (not (want :boolean (funcall x))))))
+ (:op #\+ preop "+" (x 90) (int-unop #'identity x))
+ (:op #\- preop "-" (x 90) (int-unop #'- x))
(:op #\( lparen #\)))
+ ;; Postfix operators.
((:op (when nestedp #\)) rparen #\))))
;; Do the delayed evaluation. Establish a restart so that we can
~mdw / sod / blobdiff