Hi,
I'd like to improve the error messages from mset, to clarify
why an attempted assignment fails.
Here is my proposed patch, which I think is consistent with
the recent work to provide messages that are wrapped in gettext.
I've run the test suite with the patched code, and no additional
errors are reported.
Ex:
(%i2) all:1;
assignment: cannot assign to all; it has the `neverset'
property.
-- an error. To debug this try: debugmode(true);
(%i3) %e:2.71;
assignment: cannot assign to %e; it is a declared numeric quantity.
-- an error. To debug this try: debugmode(true);
Leo
Index: src/mlisp.lisp
===================================================================
RCS file: /cvsroot/maxima/maxima/src/mlisp.lisp,v
retrieving revision 1.85
diff -u -r1.85 mlisp.lisp
--- src/mlisp.lisp 21 Mar 2010 07:06:54 -0000 1.85
+++ src/mlisp.lisp 29 Mar 2010 08:24:44 -0000
@@ -618,6 +618,9 @@
(twoargcheck l)
(mset (simplifya (cadr l) nil) (meval (caddr l))))
+(defvar *mset-error-message* ""
+ "Last error message caused by invoking mset (:)")
+
(defun mset (x y)
(prog ()
(cond ((or (null $setcheck)
@@ -633,14 +636,16 @@
(merrbreak t)
(setq y $setval)))))
(cond ((atom x)
- (when (or (not (symbolp x))
- (member x '(t nil) :test #'eq)
- (mget x '$numer)
- (get x 'sysconst))
+ (when (or (and (not (symbolp x))
+ (setf *mset-error-message* (intl:gettext "it
is not a symbolp.")))
+ (and (member x '(t nil) :test #'eq)
+ (setf *mset-error-message* (intl:gettext
"true and false are Maxima constants.")))
+ (and (mget x '$numer)
+ (setf *mset-error-message* (intl:gettext "it
is a declared numeric quantity.")))
+ (and (get x 'sysconst)
+ (setf *mset-error-message* (intl:gettext "it
is a Maxima constant."))))
(if munbindp (return nil))
- (if (mget x '$numer)
- (merror (intl:gettext "assignment: cannot assign to
~M; it is a declared numeric quantity.") x)
- (merror (intl:gettext "assignment: cannot assign to
~M") x)))
+ (merror (intl:gettext "assignment: cannot assign to ~M;
~a") x *mset-error-message*))
(let ((f (get x 'assign)))
(if (and f (or (not (eq x y))
(member f '(neverset read-only-assign) :test #'eq)))
(defmfun neverset (x assign-val)
(declare (ignore assign-val))
(if munbindp
'munbindp
- (merror (intl:gettext "assignment: cannot assign to ~:M") x)))
+ (merror (intl:gettext "assignment: cannot assign to ~:M; it has
the `neverset' property.") x)))
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