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[Emacs-diffs] master 88fefc3 7/7: ; Merge: Lisp watchpoints (Bug#24923)
|
From: |
Noam Postavsky |
|
Subject: |
[Emacs-diffs] master 88fefc3 7/7: ; Merge: Lisp watchpoints (Bug#24923) |
|
Date: |
Sat, 3 Dec 2016 01:45:05 +0000 (UTC) |
branch: master
commit 88fefc3291060f18503738aaa4e81b98f1970a55
Merge: 0fc4761 56c8178
Author: Noam Postavsky <address@hidden>
Commit: Noam Postavsky <address@hidden>
; Merge: Lisp watchpoints (Bug#24923)
---
doc/lispref/debugging.texi | 31 +++++++
doc/lispref/elisp.texi | 2 +
doc/lispref/variables.texi | 61 +++++++++++++
etc/NEWS | 5 ++
lisp/emacs-lisp/debug.el | 91 +++++++++++++++++++
lisp/frame.el | 3 +-
lisp/help-fns.el | 7 ++
src/alloc.c | 2 +-
src/buffer.c | 82 ++++++++++-------
src/bytecode.c | 4 +-
src/data.c | 213 +++++++++++++++++++++++++++++++++++++++-----
src/eval.c | 206 ++++++++++++++++++++++--------------------
src/font.c | 6 +-
src/lisp.h | 54 +++++++++--
src/lread.c | 6 +-
src/window.h | 1 -
src/xdisp.c | 23 +++--
test/src/data-tests.el | 115 ++++++++++++++++++++++++
18 files changed, 721 insertions(+), 191 deletions(-)
diff --git a/doc/lispref/debugging.texi b/doc/lispref/debugging.texi
index 6c0908a..c80b0f9 100644
--- a/doc/lispref/debugging.texi
+++ b/doc/lispref/debugging.texi
@@ -69,6 +69,7 @@ debugger recursively. @xref{Recursive Editing}.
* Error Debugging:: Entering the debugger when an error happens.
* Infinite Loops:: Stopping and debugging a program that doesn't exit.
* Function Debugging:: Entering it when a certain function is called.
+* Variable Debugging:: Entering it when a variable is modified.
* Explicit Debug:: Entering it at a certain point in the program.
* Using Debugger:: What the debugger does; what you see while in it.
* Debugger Commands:: Commands used while in the debugger.
@@ -290,6 +291,36 @@ Calling @code{cancel-debug-on-entry} does nothing to a
function which is
not currently set up to break on entry.
@end deffn
address@hidden Variable Debugging
address@hidden Entering the debugger when a variable is modified
address@hidden variable write debugging
address@hidden debugging changes to variables
+
+Sometimes a problem with a function is due to a wrong setting of a
+variable. Setting up the debugger to trigger whenever the variable is
+changed is a quick way to find the origin of the setting.
+
address@hidden Command debug-on-variable-change variable
+This function arranges for the debugger to be called whenever
address@hidden is modified.
+
+It is implemented using the watchpoint mechanism, so it inherits the
+same characteristics and limitations: all aliases of @var{variable}
+will be watched together, only dynamic variables can be watched, and
+changes to the objects referenced by variables are not detected. For
+details, see @ref{Watching Variables}.
address@hidden deffn
+
address@hidden Command cancel-debug-on-variable-change &optional variable
+This function undoes the effect of @code{debug-on-variable-change} on
address@hidden When called interactively, it prompts for
address@hidden in the minibuffer. If @var{variable} is omitted or
address@hidden, it cancels break-on-change for all variables. Calling
address@hidden does nothing to a variable
+which is not currently set up to break on change.
address@hidden deffn
+
+
@node Explicit Debug
@subsection Explicit Entry to the Debugger
@cindex debugger, explicit entry
diff --git a/doc/lispref/elisp.texi b/doc/lispref/elisp.texi
index 708bd9c..6983ab7 100644
--- a/doc/lispref/elisp.texi
+++ b/doc/lispref/elisp.texi
@@ -498,6 +498,7 @@ Variables
* Accessing Variables:: Examining values of variables whose names
are known only at run time.
* Setting Variables:: Storing new values in variables.
+* Watching Variables:: Running a function when a variable is changed.
* Variable Scoping:: How Lisp chooses among local and global values.
* Buffer-Local Variables:: Variable values in effect only in one buffer.
* File Local Variables:: Handling local variable lists in files.
@@ -642,6 +643,7 @@ The Lisp Debugger
* Error Debugging:: Entering the debugger when an error happens.
* Infinite Loops:: Stopping and debugging a program that doesn't exit.
* Function Debugging:: Entering it when a certain function is called.
+* Variable Debugging:: Entering it when a variable is modified.
* Explicit Debug:: Entering it at a certain point in the program.
* Using Debugger:: What the debugger does; what you see while in it.
* Debugger Commands:: Commands used while in the debugger.
diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi
index 4f2274f..d777e4d 100644
--- a/doc/lispref/variables.texi
+++ b/doc/lispref/variables.texi
@@ -34,6 +34,7 @@ representing the variable.
* Accessing Variables:: Examining values of variables whose names
are known only at run time.
* Setting Variables:: Storing new values in variables.
+* Watching Variables:: Running a function when a variable is changed.
* Variable Scoping:: How Lisp chooses among local and global values.
* Buffer-Local Variables:: Variable values in effect only in one buffer.
* File Local Variables:: Handling local variable lists in files.
@@ -766,6 +767,66 @@ error is signaled.
@end example
@end defun
address@hidden Watching Variables
address@hidden Running a function when a variable is changed.
address@hidden variable watchpoints
address@hidden watchpoints for Lisp variables
+
+It is sometimes useful to take some action when a variable changes its
+value. The watchpoint facility provides the means to do so. Some
+possible uses for this feature include keeping display in sync with
+variable settings, and invoking the debugger to track down unexpected
+changes to variables (@pxref{Variable Debugging}).
+
+The following functions may be used to manipulate and query the watch
+functions for a variable.
+
address@hidden add-variable-watcher symbol watch-function
+This function arranges for @var{watch-function} to be called whenever
address@hidden is modified. Modifications through aliases
+(@pxref{Variable Aliases}) will have the same effect.
+
address@hidden will be called with 4 arguments: (@var{symbol}
address@hidden @var{operation} @var{where}).
+
address@hidden is the variable being changed.
address@hidden is the value it will be changed to.
address@hidden is a symbol representing the kind of change, one of:
+`set', `let', `unlet', `makunbound', and `defvaralias'.
address@hidden is a buffer if the buffer-local value of the variable is
+being changed, nil otherwise.
address@hidden defun
+
address@hidden remove-variable-watch symbol watch-function
+This function removes @var{watch-function} from @var{symbol}'s list of
+watchers.
address@hidden defun
+
address@hidden get-variable-watchers symbol
+This function returns the list of @var{symbol}'s active watcher
+functions.
address@hidden defun
+
address@hidden Limitations
+
+There are a couple of ways in which a variable could be modifed (or at
+least appear to be modified) without triggering a watchpoint.
+
+Since watchpoints are attached to symbols, modification to the
+objects contained within variables (e.g., by a list modification
+function @pxref{Modifying Lists}) is not caught by this mechanism.
+
+Additionally, C code can modify the value of variables directly,
+bypassing the watchpoint mechanism.
+
+A minor limitation of this feature, again because it targets symbols,
+is that only variables of dynamic scope may be watched. This poses
+little difficulty, since modifications to lexical variables can be
+discovered easily by inspecting the code within the scope of the
+variable (unlike dynamic variables, which can be modified by any code
+at all, @pxref{Variable Scoping}).
+
+
@node Variable Scoping
@section Scoping Rules for Variable Bindings
@cindex scoping rule
diff --git a/etc/NEWS b/etc/NEWS
index 0d2162c..f7565b0 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -716,6 +716,11 @@ consistency with the new functions. For compatibility,
'sxhash'
remains as an alias to 'sxhash-equal'.
+++
+** New function `add-variable-watcher' can be used to call a function
+when a symbol's value is changed. This is used to implement the new
+debugger command `debug-on-variable-change'.
+
++++
** Time conversion functions that accept a time zone rule argument now
allow it to be OFFSET or a list (OFFSET ABBR), where the integer
OFFSET is a count of seconds east of Universal Time, and the string
diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 7d27380..5430b72 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -306,6 +306,24 @@ That buffer should be current already."
(delete-char 1)
(insert ? )
(beginning-of-line))
+ ;; Watchpoint triggered.
+ ((and `watchpoint (let `(,symbol ,newval . ,details) (cdr args)))
+ (insert
+ "--"
+ (pcase details
+ (`(makunbound nil) (format "making %s void" symbol))
+ (`(makunbound ,buffer) (format "killing local value of %s in buffer
%s"
+ symbol buffer))
+ (`(defvaralias ,_) (format "aliasing %s to %s" symbol newval))
+ (`(let ,_) (format "let-binding %s to %S" symbol newval))
+ (`(unlet ,_) (format "ending let-binding of %s" symbol))
+ (`(set nil) (format "setting %s to %S" symbol newval))
+ (`(set ,buffer) (format "setting %s in buffer %s to %S"
+ symbol buffer newval))
+ (_ (error "unrecognized watchpoint triggered %S" (cdr args))))
+ ": ")
+ (setq pos (point))
+ (insert ?\n))
;; Debugger entered for an error.
(`error
(insert "--Lisp error: ")
@@ -850,6 +868,79 @@ To specify a nil argument interactively, exit with an
empty minibuffer."
(princ "Note: if you have redefined a function, then it may no
longer\n")
(princ "be set to debug on entry, even if it is in the list."))))))
+(defun debug--implement-debug-watch (symbol newval op where)
+ "Conditionally call the debugger.
+This function is called when SYMBOL's value is modified."
+ (if (or inhibit-debug-on-entry debugger-jumping-flag)
+ nil
+ (let ((inhibit-debug-on-entry t))
+ (funcall debugger 'watchpoint symbol newval op where))))
+
+;;;###autoload
+(defun debug-on-variable-change (variable)
+ "Trigger a debugger invocation when VARIABLE is changed.
+
+When called interactively, prompt for VARIABLE in the minibuffer.
+
+This works by calling `add-variable-watch' on VARIABLE. If you
+quit from the debugger, this will abort the change (unless the
+change is caused by the termination of a let-binding).
+
+The watchpoint may be circumvented by C code that changes the
+variable directly (i.e., not via `set'). Changing the value of
+the variable (e.g., `setcar' on a list variable) will not trigger
+watchpoint.
+
+Use \\[cancel-debug-on-variable-change] to cancel the effect of
+this command. Uninterning VARIABLE or making it an alias of
+another symbol also cancels it."
+ (interactive
+ (let* ((var-at-point (variable-at-point))
+ (var (and (symbolp var-at-point) var-at-point))
+ (val (completing-read
+ (concat "Debug when setting variable"
+ (if var (format " (default %s): " var) ": "))
+ obarray #'boundp
+ t nil nil (and var (symbol-name var)))))
+ (list (if (equal val "") var (intern val)))))
+ (add-variable-watcher variable #'debug--implement-debug-watch))
+
+;;;###autoload
+(defalias 'debug-watch #'debug-on-variable-change)
+
+
+(defun debug--variable-list ()
+ "List of variables currently set for debug on set."
+ (let ((vars '()))
+ (mapatoms
+ (lambda (s)
+ (when (memq #'debug--implement-debug-watch
+ (get s 'watchers))
+ (push s vars))))
+ vars))
+
+;;;###autoload
+(defun cancel-debug-on-variable-change (&optional variable)
+ "Undo effect of \\[debug-on-variable-change] on VARIABLE.
+If VARIABLE is nil, cancel debug-on-variable-change for all variables.
+When called interactively, prompt for VARIABLE in the minibuffer.
+To specify a nil argument interactively, exit with an empty minibuffer."
+ (interactive
+ (list (let ((name
+ (completing-read
+ "Cancel debug on set for variable (default all variables): "
+ (mapcar #'symbol-name (debug--variable-list)) nil t)))
+ (when name
+ (unless (string= name "")
+ (intern name))))))
+ (if variable
+ (remove-variable-watcher variable #'debug--implement-debug-watch)
+ (message "Canceling debug-watch for all variables")
+ (mapc #'cancel-debug-watch (debug--variable-list))))
+
+;;;###autoload
+(defalias 'cancel-debug-watch #'cancel-debug-on-variable-change)
+
(provide 'debug)
;;; debug.el ends here
diff --git a/lisp/frame.el b/lisp/frame.el
index a584567..1dffc6c 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -2249,9 +2249,8 @@ See also `toggle-frame-maximized'."
'window-system-version "it does not give useful information." "24.3")
;; Variables which should trigger redisplay of the current buffer.
-(setq redisplay--variables (make-hash-table :test 'eq :size 10))
(mapc (lambda (var)
- (puthash var 1 redisplay--variables))
+ (add-variable-watcher var (symbol-function 'set-buffer-redisplay)))
'(line-spacing
overline-margin
line-prefix
diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 87e7d8f..23dec89 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -918,6 +918,7 @@ it is displayed along with the global value."
(indirect-variable variable)
(error variable)))
(obsolete (get variable 'byte-obsolete-variable))
+ (watchpoints (get-variable-watchers variable))
(use (car obsolete))
(safe-var (get variable 'safe-local-variable))
(doc (or (documentation-property
@@ -967,6 +968,12 @@ if it is given a local binding.\n"))))
(t ".")))
(terpri))
+ (when watchpoints
+ (setq extra-line t)
+ (princ " Calls these functions when changed: ")
+ (princ watchpoints)
+ (terpri))
+
(when (member (cons variable val)
(with-current-buffer buffer
file-local-variables-alist))
diff --git a/src/alloc.c b/src/alloc.c
index ae32400..6eced7b 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3567,7 +3567,7 @@ init_symbol (Lisp_Object val, Lisp_Object name)
set_symbol_next (val, NULL);
p->gcmarkbit = false;
p->interned = SYMBOL_UNINTERNED;
- p->constant = 0;
+ p->trapped_write = SYMBOL_UNTRAPPED_WRITE;
p->declared_special = false;
p->pinned = false;
}
diff --git a/src/buffer.c b/src/buffer.c
index aa556b7..6815aa7 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -984,40 +984,54 @@ reset_buffer_local_variables (struct buffer *b, bool
permanent_too)
bset_local_var_alist (b, Qnil);
else
{
- Lisp_Object tmp, prop, last = Qnil;
+ Lisp_Object tmp, last = Qnil;
for (tmp = BVAR (b, local_var_alist); CONSP (tmp); tmp = XCDR (tmp))
- if (!NILP (prop = Fget (XCAR (XCAR (tmp)), Qpermanent_local)))
- {
- /* If permanent-local, keep it. */
- last = tmp;
- if (EQ (prop, Qpermanent_local_hook))
- {
- /* This is a partially permanent hook variable.
- Preserve only the elements that want to be preserved. */
- Lisp_Object list, newlist;
- list = XCDR (XCAR (tmp));
- if (!CONSP (list))
- newlist = list;
- else
- for (newlist = Qnil; CONSP (list); list = XCDR (list))
- {
- Lisp_Object elt = XCAR (list);
- /* Preserve element ELT if it's t,
- if it is a function with a `permanent-local-hook'
property,
- or if it's not a symbol. */
- if (! SYMBOLP (elt)
- || EQ (elt, Qt)
- || !NILP (Fget (elt, Qpermanent_local_hook)))
- newlist = Fcons (elt, newlist);
- }
- XSETCDR (XCAR (tmp), Fnreverse (newlist));
- }
- }
- /* Delete this local variable. */
- else if (NILP (last))
- bset_local_var_alist (b, XCDR (tmp));
- else
- XSETCDR (last, XCDR (tmp));
+ {
+ Lisp_Object local_var = XCAR (XCAR (tmp));
+ Lisp_Object prop = Fget (local_var, Qpermanent_local);
+
+ if (!NILP (prop))
+ {
+ /* If permanent-local, keep it. */
+ last = tmp;
+ if (EQ (prop, Qpermanent_local_hook))
+ {
+ /* This is a partially permanent hook variable.
+ Preserve only the elements that want to be preserved. */
+ Lisp_Object list, newlist;
+ list = XCDR (XCAR (tmp));
+ if (!CONSP (list))
+ newlist = list;
+ else
+ for (newlist = Qnil; CONSP (list); list = XCDR (list))
+ {
+ Lisp_Object elt = XCAR (list);
+ /* Preserve element ELT if it's t,
+ if it is a function with a `permanent-local-hook'
property,
+ or if it's not a symbol. */
+ if (! SYMBOLP (elt)
+ || EQ (elt, Qt)
+ || !NILP (Fget (elt, Qpermanent_local_hook)))
+ newlist = Fcons (elt, newlist);
+ }
+ newlist = Fnreverse (newlist);
+ if (XSYMBOL (local_var)->trapped_write ==
SYMBOL_TRAPPED_WRITE)
+ notify_variable_watchers (local_var, newlist,
+ Qmakunbound, Fcurrent_buffer ());
+ XSETCDR (XCAR (tmp), newlist);
+ continue; /* Don't do variable write trapping twice. */
+ }
+ }
+ /* Delete this local variable. */
+ else if (NILP (last))
+ bset_local_var_alist (b, XCDR (tmp));
+ else
+ XSETCDR (last, XCDR (tmp));
+
+ if (XSYMBOL (local_var)->trapped_write == SYMBOL_TRAPPED_WRITE)
+ notify_variable_watchers (local_var, Qnil,
+ Qmakunbound, Fcurrent_buffer ());
+ }
}
for (i = 0; i < last_per_buffer_idx; ++i)
@@ -5541,7 +5555,7 @@ file I/O and the behavior of various editing commands.
This variable is buffer-local but you cannot set it directly;
use the function `set-buffer-multibyte' to change a buffer's representation.
See also Info node `(elisp)Text Representations'. */);
- XSYMBOL (intern_c_string ("enable-multibyte-characters"))->constant = 1;
+ make_symbol_constant (intern_c_string ("enable-multibyte-characters"));
DEFVAR_PER_BUFFER ("buffer-file-coding-system",
&BVAR (current_buffer, buffer_file_coding_system), Qnil,
diff --git a/src/bytecode.c b/src/bytecode.c
index be39a81..868c014 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -569,10 +569,10 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector,
Lisp_Object maxdepth,
if (SYMBOLP (sym)
&& !EQ (val, Qunbound)
&& !XSYMBOL (sym)->redirect
- && !SYMBOL_CONSTANT_P (sym))
+ && !SYMBOL_TRAPPED_WRITE_P (sym))
SET_SYMBOL_VAL (XSYMBOL (sym), val);
else
- set_internal (sym, val, Qnil, false);
+ set_internal (sym, val, Qnil, SET_INTERNAL_SET);
}
NEXT;
diff --git a/src/data.c b/src/data.c
index 61b5da8..eee2a52 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1225,7 +1225,7 @@ DEFUN ("set", Fset, Sset, 2, 2, 0,
doc: /* Set SYMBOL's value to NEWVAL, and return NEWVAL. */)
(register Lisp_Object symbol, Lisp_Object newval)
{
- set_internal (symbol, newval, Qnil, 0);
+ set_internal (symbol, newval, Qnil, SET_INTERNAL_SET);
return newval;
}
@@ -1233,13 +1233,14 @@ DEFUN ("set", Fset, Sset, 2, 2, 0,
If buffer/frame-locality is an issue, WHERE specifies which context to use.
(nil stands for the current buffer/frame).
- If BINDFLAG is false, then if this symbol is supposed to become
- local in every buffer where it is set, then we make it local.
- If BINDFLAG is true, we don't do that. */
+ If BINDFLAG is SET_INTERNAL_SET, then if this symbol is supposed to
+ become local in every buffer where it is set, then we make it
+ local. If BINDFLAG is SET_INTERNAL_BIND or SET_INTERNAL_UNBIND, we
+ don't do that. */
void
set_internal (Lisp_Object symbol, Lisp_Object newval, Lisp_Object where,
- bool bindflag)
+ enum Set_Internal_Bind bindflag)
{
bool voide = EQ (newval, Qunbound);
struct Lisp_Symbol *sym;
@@ -1250,18 +1251,29 @@ set_internal (Lisp_Object symbol, Lisp_Object newval,
Lisp_Object where,
return; */
CHECK_SYMBOL (symbol);
- if (SYMBOL_CONSTANT_P (symbol))
+ sym = XSYMBOL (symbol);
+ switch (sym->trapped_write)
{
+ case SYMBOL_NOWRITE:
if (NILP (Fkeywordp (symbol))
- || !EQ (newval, Fsymbol_value (symbol)))
- xsignal1 (Qsetting_constant, symbol);
+ || !EQ (newval, Fsymbol_value (symbol)))
+ xsignal1 (Qsetting_constant, symbol);
else
- /* Allow setting keywords to their own value. */
- return;
- }
+ /* Allow setting keywords to their own value. */
+ return;
+
+ case SYMBOL_TRAPPED_WRITE:
+ notify_variable_watchers (symbol, voide? Qnil : newval,
+ (bindflag == SET_INTERNAL_BIND? Qlet :
+ bindflag == SET_INTERNAL_UNBIND? Qunlet :
+ voide? Qmakunbound : Qset),
+ where);
+ /* FALLTHROUGH! */
+ case SYMBOL_UNTRAPPED_WRITE:
+ break;
- maybe_set_redisplay (symbol);
- sym = XSYMBOL (symbol);
+ default: emacs_abort ();
+ }
start:
switch (sym->redirect)
@@ -1385,6 +1397,130 @@ set_internal (Lisp_Object symbol, Lisp_Object newval,
Lisp_Object where,
}
return;
}
+
+static void
+set_symbol_trapped_write (Lisp_Object symbol, enum symbol_trapped_write trap)
+{
+ struct Lisp_Symbol* sym = XSYMBOL (symbol);
+ if (sym->trapped_write == SYMBOL_NOWRITE)
+ xsignal1 (Qtrapping_constant, symbol);
+ else if (sym->redirect == SYMBOL_LOCALIZED
+ && SYMBOL_BLV (sym)->frame_local)
+ xsignal1 (Qtrapping_frame_local, symbol);
+ sym->trapped_write = trap;
+}
+
+static void
+restore_symbol_trapped_write (Lisp_Object symbol)
+{
+ set_symbol_trapped_write (symbol, SYMBOL_TRAPPED_WRITE);
+}
+
+static void
+harmonize_variable_watchers (Lisp_Object alias, Lisp_Object base_variable)
+{
+ if (!EQ (base_variable, alias)
+ && EQ (base_variable, Findirect_variable (alias)))
+ set_symbol_trapped_write
+ (alias, XSYMBOL (base_variable)->trapped_write);
+}
+
+DEFUN ("add-variable-watcher", Fadd_variable_watcher, Sadd_variable_watcher,
+ 2, 2, 0,
+ doc: /* Cause WATCH-FUNCTION to be called when SYMBOL is set.
+
+It will be called with 4 arguments: (SYMBOL NEWVAL OPERATION WHERE).
+SYMBOL is the variable being changed.
+NEWVAL is the value it will be changed to.
+OPERATION is a symbol representing the kind of change, one of: `set',
+`let', `unlet', `makunbound', and `defvaralias'.
+WHERE is a buffer if the buffer-local value of the variable being
+changed, nil otherwise.
+
+All writes to aliases of SYMBOL will call WATCH-FUNCTION too. */)
+ (Lisp_Object symbol, Lisp_Object watch_function)
+{
+ symbol = Findirect_variable (symbol);
+ set_symbol_trapped_write (symbol, SYMBOL_TRAPPED_WRITE);
+ map_obarray (Vobarray, harmonize_variable_watchers, symbol);
+
+ Lisp_Object watchers = Fget (symbol, Qwatchers);
+ Lisp_Object member = Fmember (watch_function, watchers);
+ if (NILP (member))
+ Fput (symbol, Qwatchers, Fcons (watch_function, watchers));
+ return Qnil;
+}
+
+DEFUN ("remove-variable-watcher", Fremove_variable_watcher,
Sremove_variable_watcher,
+ 2, 2, 0,
+ doc: /* Undo the effect of `add-variable-watcher'.
+Remove WATCH-FUNCTION from the list of functions to be called when
+SYMBOL (or its aliases) are set. */)
+ (Lisp_Object symbol, Lisp_Object watch_function)
+{
+ symbol = Findirect_variable (symbol);
+ Lisp_Object watchers = Fget (symbol, Qwatchers);
+ watchers = Fdelete (watch_function, watchers);
+ if (NILP (watchers))
+ {
+ set_symbol_trapped_write (symbol, SYMBOL_UNTRAPPED_WRITE);
+ map_obarray (Vobarray, harmonize_variable_watchers, symbol);
+ }
+ Fput (symbol, Qwatchers, watchers);
+ return Qnil;
+}
+
+DEFUN ("get-variable-watchers", Fget_variable_watchers, Sget_variable_watchers,
+ 1, 1, 0,
+ doc: /* Return a list of SYMBOL's active watchers. */)
+ (Lisp_Object symbol)
+{
+ return (SYMBOL_TRAPPED_WRITE_P (symbol) == SYMBOL_TRAPPED_WRITE)
+ ? Fget (Findirect_variable (symbol), Qwatchers)
+ : Qnil;
+}
+
+void
+notify_variable_watchers (Lisp_Object symbol,
+ Lisp_Object newval,
+ Lisp_Object operation,
+ Lisp_Object where)
+{
+ symbol = Findirect_variable (symbol);
+
+ ptrdiff_t count = SPECPDL_INDEX ();
+ record_unwind_protect (restore_symbol_trapped_write, symbol);
+ /* Avoid recursion. */
+ set_symbol_trapped_write (symbol, SYMBOL_UNTRAPPED_WRITE);
+
+ if (NILP (where)
+ && !EQ (operation, Qset_default) && !EQ (operation, Qmakunbound)
+ && !NILP (Flocal_variable_if_set_p (symbol, Fcurrent_buffer ())))
+ {
+ XSETBUFFER (where, current_buffer);
+ }
+
+ if (EQ (operation, Qset_default))
+ operation = Qset;
+
+ for (Lisp_Object watchers = Fget (symbol, Qwatchers);
+ CONSP (watchers);
+ watchers = XCDR (watchers))
+ {
+ Lisp_Object watcher = XCAR (watchers);
+ /* Call subr directly to avoid gc. */
+ if (SUBRP (watcher))
+ {
+ Lisp_Object args[] = { symbol, newval, operation, where };
+ funcall_subr (XSUBR (watcher), ARRAYELTS (args), args);
+ }
+ else
+ CALLN (Ffuncall, watcher, symbol, newval, operation, where);
+ }
+
+ unbind_to (count, Qnil);
+}
+
/* Access or set a buffer-local symbol's default value. */
@@ -1471,16 +1607,27 @@ for this variable. */)
struct Lisp_Symbol *sym;
CHECK_SYMBOL (symbol);
- if (SYMBOL_CONSTANT_P (symbol))
+ sym = XSYMBOL (symbol);
+ switch (sym->trapped_write)
{
+ case SYMBOL_NOWRITE:
if (NILP (Fkeywordp (symbol))
- || !EQ (value, Fdefault_value (symbol)))
- xsignal1 (Qsetting_constant, symbol);
+ || !EQ (value, Fsymbol_value (symbol)))
+ xsignal1 (Qsetting_constant, symbol);
else
- /* Allow setting keywords to their own value. */
- return value;
+ /* Allow setting keywords to their own value. */
+ return value;
+
+ case SYMBOL_TRAPPED_WRITE:
+ /* Don't notify here if we're going to call Fset anyway. */
+ if (sym->redirect != SYMBOL_PLAINVAL)
+ notify_variable_watchers (symbol, value, Qset_default, Qnil);
+ /* FALLTHROUGH! */
+ case SYMBOL_UNTRAPPED_WRITE:
+ break;
+
+ default: emacs_abort ();
}
- sym = XSYMBOL (symbol);
start:
switch (sym->redirect)
@@ -1651,7 +1798,7 @@ The function `default-value' gets the default value and
`set-default' sets it.
default: emacs_abort ();
}
- if (sym->constant)
+ if (SYMBOL_CONSTANT_P (variable))
error ("Symbol %s may not be buffer-local", SDATA (SYMBOL_NAME
(variable)));
if (!blv)
@@ -1726,7 +1873,7 @@ Instead, use `add-hook' and specify t for the LOCAL
argument. */)
default: emacs_abort ();
}
- if (sym->constant)
+ if (sym->trapped_write == SYMBOL_NOWRITE)
error ("Symbol %s may not be buffer-local",
SDATA (SYMBOL_NAME (variable)));
@@ -1838,6 +1985,9 @@ From now on the default value will apply in this buffer.
Return VARIABLE. */)
default: emacs_abort ();
}
+ if (sym->trapped_write == SYMBOL_TRAPPED_WRITE)
+ notify_variable_watchers (variable, Qnil, Qmakunbound, Fcurrent_buffer ());
+
/* Get rid of this buffer's alist element, if any. */
XSETSYMBOL (variable, sym); /* Propagate variable indirection. */
tem = Fassq (variable, BVAR (current_buffer, local_var_alist));
@@ -1920,7 +2070,7 @@ frame-local bindings). */)
default: emacs_abort ();
}
- if (sym->constant)
+ if (SYMBOL_TRAPPED_WRITE_P (variable))
error ("Symbol %s may not be frame-local", SDATA (SYMBOL_NAME (variable)));
blv = make_blv (sym, forwarded, valcontents);
@@ -3465,6 +3615,8 @@ syms_of_data (void)
DEFSYM (Qcyclic_variable_indirection, "cyclic-variable-indirection");
DEFSYM (Qvoid_variable, "void-variable");
DEFSYM (Qsetting_constant, "setting-constant");
+ DEFSYM (Qtrapping_constant, "trapping-constant");
+ DEFSYM (Qtrapping_frame_local, "trapping-frame-local");
DEFSYM (Qinvalid_read_syntax, "invalid-read-syntax");
DEFSYM (Qinvalid_function, "invalid-function");
@@ -3543,6 +3695,10 @@ syms_of_data (void)
PUT_ERROR (Qvoid_variable, error_tail, "Symbol's value as variable is void");
PUT_ERROR (Qsetting_constant, error_tail,
"Attempt to set a constant symbol");
+ PUT_ERROR (Qtrapping_constant, error_tail,
+ "Attempt to trap writes to a constant symbol");
+ PUT_ERROR (Qtrapping_frame_local, error_tail,
+ "Attempt to trap writes to a frame local variable");
PUT_ERROR (Qinvalid_read_syntax, error_tail, "Invalid read syntax");
PUT_ERROR (Qinvalid_function, error_tail, "Invalid function");
PUT_ERROR (Qwrong_number_of_arguments, error_tail,
@@ -3721,10 +3877,19 @@ syms_of_data (void)
DEFVAR_LISP ("most-positive-fixnum", Vmost_positive_fixnum,
doc: /* The largest value that is representable in a Lisp
integer. */);
Vmost_positive_fixnum = make_number (MOST_POSITIVE_FIXNUM);
- XSYMBOL (intern_c_string ("most-positive-fixnum"))->constant = 1;
+ make_symbol_constant (intern_c_string ("most-positive-fixnum"));
DEFVAR_LISP ("most-negative-fixnum", Vmost_negative_fixnum,
doc: /* The smallest value that is representable in a Lisp
integer. */);
Vmost_negative_fixnum = make_number (MOST_NEGATIVE_FIXNUM);
- XSYMBOL (intern_c_string ("most-negative-fixnum"))->constant = 1;
+ make_symbol_constant (intern_c_string ("most-negative-fixnum"));
+
+ DEFSYM (Qwatchers, "watchers");
+ DEFSYM (Qmakunbound, "makunbound");
+ DEFSYM (Qunlet, "unlet");
+ DEFSYM (Qset, "set");
+ DEFSYM (Qset_default, "set-default");
+ defsubr (&Sadd_variable_watcher);
+ defsubr (&Sremove_variable_watcher);
+ defsubr (&Sget_variable_watchers);
}
diff --git a/src/eval.c b/src/eval.c
index bbc1518..724f001 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -593,12 +593,12 @@ The return value is BASE-VARIABLE. */)
CHECK_SYMBOL (new_alias);
CHECK_SYMBOL (base_variable);
- sym = XSYMBOL (new_alias);
-
- if (sym->constant)
- /* Not sure why, but why not? */
+ if (SYMBOL_CONSTANT_P (new_alias))
+ /* Making it an alias effectively changes its value. */
error ("Cannot make a constant an alias");
+ sym = XSYMBOL (new_alias);
+
switch (sym->redirect)
{
case SYMBOL_FORWARDED:
@@ -617,8 +617,8 @@ The return value is BASE-VARIABLE. */)
so that old-code that affects n_a before the aliasing is setup
still works. */
if (NILP (Fboundp (base_variable)))
- set_internal (base_variable, find_symbol_value (new_alias), Qnil, 1);
-
+ set_internal (base_variable, find_symbol_value (new_alias),
+ Qnil, SET_INTERNAL_BIND);
{
union specbinding *p;
@@ -628,11 +628,14 @@ The return value is BASE-VARIABLE. */)
error ("Don't know how to make a let-bound variable an alias");
}
+ if (sym->trapped_write == SYMBOL_TRAPPED_WRITE)
+ notify_variable_watchers (new_alias, base_variable, Qdefvaralias, Qnil);
+
sym->declared_special = 1;
XSYMBOL (base_variable)->declared_special = 1;
sym->redirect = SYMBOL_VARALIAS;
SET_SYMBOL_ALIAS (sym, XSYMBOL (base_variable));
- sym->constant = SYMBOL_CONSTANT_P (base_variable);
+ sym->trapped_write = XSYMBOL (base_variable)->trapped_write;
LOADHIST_ATTACH (new_alias);
/* Even if docstring is nil: remove old docstring. */
Fput (new_alias, Qvariable_documentation, docstring);
@@ -2645,9 +2648,7 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */)
Lisp_Object fun, original_fun;
Lisp_Object funcar;
ptrdiff_t numargs = nargs - 1;
- Lisp_Object lisp_numargs;
Lisp_Object val;
- Lisp_Object *internal_args;
ptrdiff_t count;
QUIT;
@@ -2680,86 +2681,7 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */)
fun = indirect_function (fun);
if (SUBRP (fun))
- {
- if (numargs < XSUBR (fun)->min_args
- || (XSUBR (fun)->max_args >= 0 && XSUBR (fun)->max_args < numargs))
- {
- XSETFASTINT (lisp_numargs, numargs);
- xsignal2 (Qwrong_number_of_arguments, original_fun, lisp_numargs);
- }
-
- else if (XSUBR (fun)->max_args == UNEVALLED)
- xsignal1 (Qinvalid_function, original_fun);
-
- else if (XSUBR (fun)->max_args == MANY)
- val = (XSUBR (fun)->function.aMANY) (numargs, args + 1);
- else
- {
- Lisp_Object internal_argbuf[8];
- if (XSUBR (fun)->max_args > numargs)
- {
- eassert (XSUBR (fun)->max_args <= ARRAYELTS (internal_argbuf));
- internal_args = internal_argbuf;
- memcpy (internal_args, args + 1, numargs * word_size);
- memclear (internal_args + numargs,
- (XSUBR (fun)->max_args - numargs) * word_size);
- }
- else
- internal_args = args + 1;
- switch (XSUBR (fun)->max_args)
- {
- case 0:
- val = (XSUBR (fun)->function.a0 ());
- break;
- case 1:
- val = (XSUBR (fun)->function.a1 (internal_args[0]));
- break;
- case 2:
- val = (XSUBR (fun)->function.a2
- (internal_args[0], internal_args[1]));
- break;
- case 3:
- val = (XSUBR (fun)->function.a3
- (internal_args[0], internal_args[1], internal_args[2]));
- break;
- case 4:
- val = (XSUBR (fun)->function.a4
- (internal_args[0], internal_args[1], internal_args[2],
- internal_args[3]));
- break;
- case 5:
- val = (XSUBR (fun)->function.a5
- (internal_args[0], internal_args[1], internal_args[2],
- internal_args[3], internal_args[4]));
- break;
- case 6:
- val = (XSUBR (fun)->function.a6
- (internal_args[0], internal_args[1], internal_args[2],
- internal_args[3], internal_args[4], internal_args[5]));
- break;
- case 7:
- val = (XSUBR (fun)->function.a7
- (internal_args[0], internal_args[1], internal_args[2],
- internal_args[3], internal_args[4], internal_args[5],
- internal_args[6]));
- break;
-
- case 8:
- val = (XSUBR (fun)->function.a8
- (internal_args[0], internal_args[1], internal_args[2],
- internal_args[3], internal_args[4], internal_args[5],
- internal_args[6], internal_args[7]));
- break;
-
- default:
-
- /* If a subr takes more than 8 arguments without using MANY
- or UNEVALLED, we need to extend this function to support it.
- Until this is done, there is no way to call the function. */
- emacs_abort ();
- }
- }
- }
+ val = funcall_subr (XSUBR (fun), numargs, args + 1);
else if (COMPILEDP (fun))
val = funcall_lambda (fun, numargs, args + 1);
else
@@ -2791,6 +2713,89 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */)
return val;
}
+
+/* Apply a C subroutine SUBR to the NUMARGS evaluated arguments in ARG_VECTOR
+ and return the result of evaluation. */
+
+Lisp_Object
+funcall_subr (struct Lisp_Subr *subr, ptrdiff_t numargs, Lisp_Object *args)
+{
+ if (numargs < subr->min_args
+ || (subr->max_args >= 0 && subr->max_args < numargs))
+ {
+ Lisp_Object fun;
+ XSETSUBR (fun, subr);
+ xsignal2 (Qwrong_number_of_arguments, fun, make_number (numargs));
+ }
+
+ else if (subr->max_args == UNEVALLED)
+ {
+ Lisp_Object fun;
+ XSETSUBR (fun, subr);
+ xsignal1 (Qinvalid_function, fun);
+ }
+
+ else if (subr->max_args == MANY)
+ return (subr->function.aMANY) (numargs, args);
+ else
+ {
+ Lisp_Object internal_argbuf[8];
+ Lisp_Object *internal_args;
+ if (subr->max_args > numargs)
+ {
+ eassert (subr->max_args <= ARRAYELTS (internal_argbuf));
+ internal_args = internal_argbuf;
+ memcpy (internal_args, args, numargs * word_size);
+ memclear (internal_args + numargs,
+ (subr->max_args - numargs) * word_size);
+ }
+ else
+ internal_args = args;
+ switch (subr->max_args)
+ {
+ case 0:
+ return (subr->function.a0 ());
+ case 1:
+ return (subr->function.a1 (internal_args[0]));
+ case 2:
+ return (subr->function.a2
+ (internal_args[0], internal_args[1]));
+ case 3:
+ return (subr->function.a3
+ (internal_args[0], internal_args[1], internal_args[2]));
+ case 4:
+ return (subr->function.a4
+ (internal_args[0], internal_args[1], internal_args[2],
+ internal_args[3]));
+ case 5:
+ return (subr->function.a5
+ (internal_args[0], internal_args[1], internal_args[2],
+ internal_args[3], internal_args[4]));
+ case 6:
+ return (subr->function.a6
+ (internal_args[0], internal_args[1], internal_args[2],
+ internal_args[3], internal_args[4], internal_args[5]));
+ case 7:
+ return (subr->function.a7
+ (internal_args[0], internal_args[1], internal_args[2],
+ internal_args[3], internal_args[4], internal_args[5],
+ internal_args[6]));
+ case 8:
+ return (subr->function.a8
+ (internal_args[0], internal_args[1], internal_args[2],
+ internal_args[3], internal_args[4], internal_args[5],
+ internal_args[6], internal_args[7]));
+
+ default:
+
+ /* If a subr takes more than 8 arguments without using MANY
+ or UNEVALLED, we need to extend this function to support it.
+ Until this is done, there is no way to call the function. */
+ emacs_abort ();
+ }
+ }
+}
+
static Lisp_Object
apply_lambda (Lisp_Object fun, Lisp_Object args, ptrdiff_t count)
{
@@ -3171,10 +3176,10 @@ specbind (Lisp_Object symbol, Lisp_Object value)
specpdl_ptr->let.symbol = symbol;
specpdl_ptr->let.old_value = SYMBOL_VAL (sym);
grow_specpdl ();
- if (!sym->constant)
+ if (!sym->trapped_write)
SET_SYMBOL_VAL (sym, value);
else
- set_internal (symbol, value, Qnil, 1);
+ set_internal (symbol, value, Qnil, SET_INTERNAL_BIND);
break;
case SYMBOL_LOCALIZED:
if (SYMBOL_BLV (sym)->frame_local)
@@ -3214,7 +3219,7 @@ specbind (Lisp_Object symbol, Lisp_Object value)
specpdl_ptr->let.kind = SPECPDL_LET;
grow_specpdl ();
- set_internal (symbol, value, Qnil, 1);
+ set_internal (symbol, value, Qnil, SET_INTERNAL_BIND);
break;
}
default: emacs_abort ();
@@ -3341,14 +3346,16 @@ unbind_to (ptrdiff_t count, Lisp_Object value)
case SPECPDL_BACKTRACE:
break;
case SPECPDL_LET:
- { /* If variable has a trivial value (no forwarding), we can
- just set it. No need to check for constant symbols here,
- since that was already done by specbind. */
+ { /* If variable has a trivial value (no forwarding), and
+ isn't trapped, we can just set it. */
Lisp_Object sym = specpdl_symbol (specpdl_ptr);
if (SYMBOLP (sym) && XSYMBOL (sym)->redirect == SYMBOL_PLAINVAL)
{
- SET_SYMBOL_VAL (XSYMBOL (sym),
- specpdl_old_value (specpdl_ptr));
+ if (XSYMBOL (sym)->trapped_write == SYMBOL_UNTRAPPED_WRITE)
+ SET_SYMBOL_VAL (XSYMBOL (sym), specpdl_old_value
(specpdl_ptr));
+ else
+ set_internal (sym, specpdl_old_value (specpdl_ptr),
+ Qnil, SET_INTERNAL_UNBIND);
break;
}
else
@@ -3371,7 +3378,7 @@ unbind_to (ptrdiff_t count, Lisp_Object value)
/* If this was a local binding, reset the value in the appropriate
buffer, but only if that buffer's binding still exists. */
if (!NILP (Flocal_variable_p (symbol, where)))
- set_internal (symbol, old_value, where, 1);
+ set_internal (symbol, old_value, where, SET_INTERNAL_UNBIND);
}
break;
}
@@ -3596,7 +3603,7 @@ backtrace_eval_unrewind (int distance)
{
set_specpdl_old_value
(tmp, Fbuffer_local_value (symbol, where));
- set_internal (symbol, old_value, where, 1);
+ set_internal (symbol, old_value, where, SET_INTERNAL_UNBIND);
}
}
break;
@@ -3940,6 +3947,7 @@ alist of active lexical bindings. */);
defsubr (&Sset_default_toplevel_value);
defsubr (&Sdefvar);
defsubr (&Sdefvaralias);
+ DEFSYM (Qdefvaralias, "defvaralias");
defsubr (&Sdefconst);
defsubr (&Smake_var_non_special);
defsubr (&Slet);
diff --git a/src/font.c b/src/font.c
index 9fe7c26..36e7166 100644
--- a/src/font.c
+++ b/src/font.c
@@ -5415,19 +5415,19 @@ Each element has the form:
[NUMERIC-VALUE SYMBOLIC-NAME ALIAS-NAME ...]
NUMERIC-VALUE is an integer, and SYMBOLIC-NAME and ALIAS-NAME are symbols. */);
Vfont_weight_table = BUILD_STYLE_TABLE (weight_table);
- XSYMBOL (intern_c_string ("font-weight-table"))->constant = 1;
+ make_symbol_constant (intern_c_string ("font-weight-table"));
DEFVAR_LISP_NOPRO ("font-slant-table", Vfont_slant_table,
doc: /* Vector of font slant symbols vs the corresponding
numeric values.
See `font-weight-table' for the format of the vector. */);
Vfont_slant_table = BUILD_STYLE_TABLE (slant_table);
- XSYMBOL (intern_c_string ("font-slant-table"))->constant = 1;
+ make_symbol_constant (intern_c_string ("font-slant-table"));
DEFVAR_LISP_NOPRO ("font-width-table", Vfont_width_table,
doc: /* Alist of font width symbols vs the corresponding
numeric values.
See `font-weight-table' for the format of the vector. */);
Vfont_width_table = BUILD_STYLE_TABLE (width_table);
- XSYMBOL (intern_c_string ("font-width-table"))->constant = 1;
+ make_symbol_constant (intern_c_string ("font-width-table"));
staticpro (&font_style_table);
font_style_table = make_uninit_vector (3);
diff --git a/src/lisp.h b/src/lisp.h
index b6c4668..94f1152 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -320,7 +320,8 @@ error !;
#define lisp_h_NILP(x) EQ (x, Qnil)
#define lisp_h_SET_SYMBOL_VAL(sym, v) \
(eassert ((sym)->redirect == SYMBOL_PLAINVAL), (sym)->val.value = (v))
-#define lisp_h_SYMBOL_CONSTANT_P(sym) (XSYMBOL (sym)->constant)
+#define lisp_h_SYMBOL_CONSTANT_P(sym) (XSYMBOL (sym)->trapped_write ==
SYMBOL_NOWRITE)
+#define lisp_h_SYMBOL_TRAPPED_WRITE_P(sym) (XSYMBOL (sym)->trapped_write)
#define lisp_h_SYMBOL_VAL(sym) \
(eassert ((sym)->redirect == SYMBOL_PLAINVAL), (sym)->val.value)
#define lisp_h_SYMBOLP(x) (XTYPE (x) == Lisp_Symbol)
@@ -375,6 +376,7 @@ error !;
# define NILP(x) lisp_h_NILP (x)
# define SET_SYMBOL_VAL(sym, v) lisp_h_SET_SYMBOL_VAL (sym, v)
# define SYMBOL_CONSTANT_P(sym) lisp_h_SYMBOL_CONSTANT_P (sym)
+# define SYMBOL_TRAPPED_WRITE_P(sym) lisp_h_SYMBOL_TRAPPED_WRITE_P (sym)
# define SYMBOL_VAL(sym) lisp_h_SYMBOL_VAL (sym)
# define SYMBOLP(x) lisp_h_SYMBOLP (x)
# define VECTORLIKEP(x) lisp_h_VECTORLIKEP (x)
@@ -600,6 +602,9 @@ extern void char_table_set (Lisp_Object, int, Lisp_Object);
/* Defined in data.c. */
extern _Noreturn Lisp_Object wrong_type_argument (Lisp_Object, Lisp_Object);
extern _Noreturn void wrong_choice (Lisp_Object, Lisp_Object);
+extern void notify_variable_watchers (Lisp_Object symbol, Lisp_Object newval,
+ Lisp_Object operation, Lisp_Object
where);
+
#ifdef CANNOT_DUMP
enum { might_dump = false };
@@ -632,6 +637,13 @@ enum symbol_redirect
SYMBOL_FORWARDED = 3
};
+enum symbol_trapped_write
+{
+ SYMBOL_UNTRAPPED_WRITE = 0,
+ SYMBOL_NOWRITE = 1,
+ SYMBOL_TRAPPED_WRITE = 2
+};
+
struct Lisp_Symbol
{
bool_bf gcmarkbit : 1;
@@ -643,10 +655,10 @@ struct Lisp_Symbol
3 : it's a forwarding variable, the value is in `forward'. */
ENUM_BF (symbol_redirect) redirect : 3;
- /* Non-zero means symbol is constant, i.e. changing its value
- should signal an error. If the value is 3, then the var
- can be changed, but only by `defconst'. */
- unsigned constant : 2;
+ /* 0 : normal case, just set the value
+ 1 : constant, cannot set, e.g. nil, t, :keywords.
+ 2 : trap the write, call watcher functions. */
+ ENUM_BF (symbol_trapped_write) trapped_write : 2;
/* Interned state of the symbol. This is an enumerator from
enum symbol_interned. */
@@ -1850,9 +1862,20 @@ SYMBOL_INTERNED_IN_INITIAL_OBARRAY_P (Lisp_Object sym)
return XSYMBOL (sym)->interned == SYMBOL_INTERNED_IN_INITIAL_OBARRAY;
}
-/* Value is non-zero if symbol is considered a constant, i.e. its
- value cannot be changed (there is an exception for keyword symbols,
- whose value can be set to the keyword symbol itself). */
+/* Value is non-zero if symbol cannot be changed through a simple set,
+ i.e. it's a constant (e.g. nil, t, :keywords), or it has some
+ watching functions. */
+
+INLINE int
+(SYMBOL_TRAPPED_WRITE_P) (Lisp_Object sym)
+{
+ return lisp_h_SYMBOL_TRAPPED_WRITE_P (sym);
+}
+
+/* Value is non-zero if symbol cannot be changed at all, i.e. it's a
+ constant (e.g. nil, t, :keywords). Code that actually wants to
+ write to SYM, should also check whether there are any watching
+ functions. */
INLINE int
(SYMBOL_CONSTANT_P) (Lisp_Object sym)
@@ -3286,6 +3309,12 @@ set_symbol_next (Lisp_Object sym, struct Lisp_Symbol
*next)
XSYMBOL (sym)->next = next;
}
+INLINE void
+make_symbol_constant (Lisp_Object sym)
+{
+ XSYMBOL (sym)->trapped_write = SYMBOL_NOWRITE;
+}
+
/* Buffer-local (also frame-local) variable access functions. */
INLINE int
@@ -3394,7 +3423,13 @@ extern _Noreturn void args_out_of_range (Lisp_Object,
Lisp_Object);
extern _Noreturn void args_out_of_range_3 (Lisp_Object, Lisp_Object,
Lisp_Object);
extern Lisp_Object do_symval_forwarding (union Lisp_Fwd *);
-extern void set_internal (Lisp_Object, Lisp_Object, Lisp_Object, bool);
+enum Set_Internal_Bind {
+ SET_INTERNAL_SET,
+ SET_INTERNAL_BIND,
+ SET_INTERNAL_UNBIND
+};
+extern void set_internal (Lisp_Object, Lisp_Object, Lisp_Object,
+ enum Set_Internal_Bind);
extern void syms_of_data (void);
extern void swap_in_global_binding (struct Lisp_Symbol *);
@@ -3877,6 +3912,7 @@ extern _Noreturn void xsignal2 (Lisp_Object, Lisp_Object,
Lisp_Object);
extern _Noreturn void xsignal3 (Lisp_Object, Lisp_Object, Lisp_Object,
Lisp_Object);
extern _Noreturn void signal_error (const char *, Lisp_Object);
+extern Lisp_Object funcall_subr (struct Lisp_Subr *subr, ptrdiff_t numargs,
Lisp_Object *arg_vector);
extern Lisp_Object eval_sub (Lisp_Object form);
extern Lisp_Object apply1 (Lisp_Object, Lisp_Object);
extern Lisp_Object call0 (Lisp_Object);
diff --git a/src/lread.c b/src/lread.c
index eab9b8b..14f9393 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -3833,7 +3833,7 @@ intern_sym (Lisp_Object sym, Lisp_Object obarray,
Lisp_Object index)
if (SREF (SYMBOL_NAME (sym), 0) == ':' && EQ (obarray, initial_obarray))
{
- XSYMBOL (sym)->constant = 1;
+ make_symbol_constant (sym);
XSYMBOL (sym)->redirect = SYMBOL_PLAINVAL;
SET_SYMBOL_VAL (XSYMBOL (sym), sym);
}
@@ -4120,12 +4120,12 @@ init_obarray (void)
DEFSYM (Qnil, "nil");
SET_SYMBOL_VAL (XSYMBOL (Qnil), Qnil);
- XSYMBOL (Qnil)->constant = 1;
+ make_symbol_constant (Qnil);
XSYMBOL (Qnil)->declared_special = true;
DEFSYM (Qt, "t");
SET_SYMBOL_VAL (XSYMBOL (Qt), Qt);
- XSYMBOL (Qt)->constant = 1;
+ make_symbol_constant (Qt);
XSYMBOL (Qt)->declared_special = true;
/* Qt is correct even if CANNOT_DUMP. loadup.el will set to nil at end. */
diff --git a/src/window.h b/src/window.h
index a124b33..4a102f2 100644
--- a/src/window.h
+++ b/src/window.h
@@ -1063,7 +1063,6 @@ extern void wset_redisplay (struct window *w);
extern void fset_redisplay (struct frame *f);
extern void bset_redisplay (struct buffer *b);
extern void bset_update_mode_line (struct buffer *b);
-extern void maybe_set_redisplay (Lisp_Object);
/* Call this to tell redisplay to look for other windows than selected-window
that need to be redisplayed. Calling one of the *set_redisplay functions
above already does it, so it's only needed in unusual cases. */
diff --git a/src/xdisp.c b/src/xdisp.c
index 2acdfa9..ad0b968 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -622,15 +622,15 @@ bset_update_mode_line (struct buffer *b)
b->text->redisplay = true;
}
-void
-maybe_set_redisplay (Lisp_Object symbol)
-{
- if (HASH_TABLE_P (Vredisplay__variables)
- && hash_lookup (XHASH_TABLE (Vredisplay__variables), symbol, NULL) >= 0)
- {
- bset_update_mode_line (current_buffer);
- current_buffer->prevent_redisplay_optimizations_p = true;
- }
+DEFUN ("set-buffer-redisplay", Fset_buffer_redisplay,
+ Sset_buffer_redisplay, 4, 4, 0,
+ doc: /* Mark the current buffer for redisplay.
+This function may be passed to `add-variable-watcher'. */)
+ (Lisp_Object symbol, Lisp_Object newval, Lisp_Object op, Lisp_Object where)
+{
+ bset_update_mode_line (current_buffer);
+ current_buffer->prevent_redisplay_optimizations_p = true;
+ return Qnil;
}
#ifdef GLYPH_DEBUG
@@ -31322,6 +31322,7 @@ They are still logged to the *Messages* buffer. */);
message_dolog_marker3 = Fmake_marker ();
staticpro (&message_dolog_marker3);
+ defsubr (&Sset_buffer_redisplay);
#ifdef GLYPH_DEBUG
defsubr (&Sdump_frame_glyph_matrix);
defsubr (&Sdump_glyph_matrix);
@@ -31991,10 +31992,6 @@ display table takes effect; in this case, Emacs does
not consult
doc: /* */);
Vredisplay__mode_lines_cause = Fmake_hash_table (0, NULL);
- DEFVAR_LISP ("redisplay--variables", Vredisplay__variables,
- doc: /* A hash-table of variables changing which triggers a thorough
redisplay. */);
- Vredisplay__variables = Qnil;
-
DEFVAR_BOOL ("redisplay--inhibit-bidi", redisplay__inhibit_bidi,
doc: /* Non-nil means it is not safe to attempt bidi reordering for
display. */);
/* Initialize to t, since we need to disable reordering until
diff --git a/test/src/data-tests.el b/test/src/data-tests.el
index 0a29233..4c2ea54 100644
--- a/test/src/data-tests.el
+++ b/test/src/data-tests.el
@@ -255,3 +255,118 @@ comparing the subr with a much slower lisp
implementation."
(v2 (test-bool-vector-bv-from-hex-string "0000C"))
(v3 (bool-vector-not v1)))
(should (equal v2 v3))))
+
+(ert-deftest data-tests-variable-watchers ()
+ (defvar data-tests-var 0)
+ (let* ((watch-data nil)
+ (collect-watch-data
+ (lambda (&rest args) (push args watch-data))))
+ (cl-flet ((should-have-watch-data (data)
+ (should (equal (pop watch-data) data))
+ (should (null watch-data))))
+ (add-variable-watcher 'data-tests-var collect-watch-data)
+ (setq data-tests-var 1)
+ (should-have-watch-data '(data-tests-var 1 set nil))
+ (let ((data-tests-var 2))
+ (should-have-watch-data '(data-tests-var 2 let nil))
+ (setq data-tests-var 3)
+ (should-have-watch-data '(data-tests-var 3 set nil)))
+ (should-have-watch-data '(data-tests-var 1 unlet nil))
+ ;; `setq-default' on non-local variable is same as `setq'.
+ (setq-default data-tests-var 4)
+ (should-have-watch-data '(data-tests-var 4 set nil))
+ (makunbound 'data-tests-var)
+ (should-have-watch-data '(data-tests-var nil makunbound nil))
+ (setq data-tests-var 5)
+ (should-have-watch-data '(data-tests-var 5 set nil))
+ (remove-variable-watcher 'data-tests-var collect-watch-data)
+ (setq data-tests-var 6)
+ (should (null watch-data)))))
+
+(ert-deftest data-tests-varalias-watchers ()
+ (defvar data-tests-var0 0)
+ (defvar data-tests-var1 0)
+ (defvar data-tests-var2 0)
+ (defvar data-tests-var3 0)
+ (let* ((watch-data nil)
+ (collect-watch-data
+ (lambda (&rest args) (push args watch-data))))
+ (cl-flet ((should-have-watch-data (data)
+ (should (equal (pop watch-data) data))
+ (should (null watch-data))))
+ ;; Watch var0, then alias it.
+ (add-variable-watcher 'data-tests-var0 collect-watch-data)
+ (defvaralias 'data-tests-var0-alias 'data-tests-var0)
+ (setq data-tests-var0 1)
+ (should-have-watch-data '(data-tests-var0 1 set nil))
+ (setq data-tests-var0-alias 2)
+ (should-have-watch-data '(data-tests-var0 2 set nil))
+ ;; Alias var1, then watch var1-alias.
+ (defvaralias 'data-tests-var1-alias 'data-tests-var1)
+ (add-variable-watcher 'data-tests-var1-alias collect-watch-data)
+ (setq data-tests-var1 1)
+ (should-have-watch-data '(data-tests-var1 1 set nil))
+ (setq data-tests-var1-alias 2)
+ (should-have-watch-data '(data-tests-var1 2 set nil))
+ ;; Alias var2, then watch it.
+ (defvaralias 'data-tests-var2-alias 'data-tests-var2)
+ (add-variable-watcher 'data-tests-var2 collect-watch-data)
+ (setq data-tests-var2 1)
+ (should-have-watch-data '(data-tests-var2 1 set nil))
+ (setq data-tests-var2-alias 2)
+ (should-have-watch-data '(data-tests-var2 2 set nil))
+ ;; Watch var3-alias, then make it alias var3 (this removes the
+ ;; watcher flag).
+ (defvar data-tests-var3-alias 0)
+ (add-variable-watcher 'data-tests-var3-alias collect-watch-data)
+ (defvaralias 'data-tests-var3-alias 'data-tests-var3)
+ (should-have-watch-data '(data-tests-var3-alias
+ data-tests-var3 defvaralias nil))
+ (setq data-tests-var3 1)
+ (setq data-tests-var3-alias 2)
+ (should (null watch-data)))))
+
+(ert-deftest data-tests-local-variable-watchers ()
+ (defvar-local data-tests-lvar 0)
+ (let* ((buf1 (current-buffer))
+ (buf2 nil)
+ (watch-data nil)
+ (collect-watch-data
+ (lambda (&rest args) (push args watch-data))))
+ (cl-flet ((should-have-watch-data (data)
+ (should (equal (pop watch-data) data))
+ (should (null watch-data))))
+ (add-variable-watcher 'data-tests-lvar collect-watch-data)
+ (setq data-tests-lvar 1)
+ (should-have-watch-data `(data-tests-lvar 1 set ,buf1))
+ (let ((data-tests-lvar 2))
+ (should-have-watch-data `(data-tests-lvar 2 let ,buf1))
+ (setq data-tests-lvar 3)
+ (should-have-watch-data `(data-tests-lvar 3 set ,buf1)))
+ (should-have-watch-data `(data-tests-lvar 1 unlet ,buf1))
+ (setq-default data-tests-lvar 4)
+ (should-have-watch-data `(data-tests-lvar 4 set nil))
+ (with-temp-buffer
+ (setq buf2 (current-buffer))
+ (setq data-tests-lvar 1)
+ (should-have-watch-data `(data-tests-lvar 1 set ,buf2))
+ (let ((data-tests-lvar 2))
+ (should-have-watch-data `(data-tests-lvar 2 let ,buf2))
+ (setq data-tests-lvar 3)
+ (should-have-watch-data `(data-tests-lvar 3 set ,buf2)))
+ (should-have-watch-data `(data-tests-lvar 1 unlet ,buf2))
+ (kill-local-variable 'data-tests-lvar)
+ (should-have-watch-data `(data-tests-lvar nil makunbound ,buf2))
+ (setq data-tests-lvar 3.5)
+ (should-have-watch-data `(data-tests-lvar 3.5 set ,buf2))
+ (kill-all-local-variables)
+ (should-have-watch-data `(data-tests-lvar nil makunbound ,buf2)))
+ (setq-default data-tests-lvar 4)
+ (should-have-watch-data `(data-tests-lvar 4 set nil))
+ (makunbound 'data-tests-lvar)
+ (should-have-watch-data '(data-tests-lvar nil makunbound nil))
+ (setq data-tests-lvar 5)
+ (should-have-watch-data `(data-tests-lvar 5 set ,buf1))
+ (remove-variable-watcher 'data-tests-lvar collect-watch-data)
+ (setq data-tests-lvar 6)
+ (should (null watch-data)))))
- [Emacs-diffs] master updated (0fc4761 -> 88fefc3), Noam Postavsky, 2016/12/02
- [Emacs-diffs] master 459a234 2/7: Show watchpoints when describing variables, Noam Postavsky, 2016/12/02
- [Emacs-diffs] master cfd2b9e 3/7: Add function to trigger debugger on variable write, Noam Postavsky, 2016/12/02
- [Emacs-diffs] master d3faef9 4/7: Ensure redisplay using variable watcher, Noam Postavsky, 2016/12/02
- [Emacs-diffs] master e7cd98b 5/7: Add tests for watchpoints, Noam Postavsky, 2016/12/02
- [Emacs-diffs] master 56c8178 6/7: Document watchpoints, Noam Postavsky, 2016/12/02
- [Emacs-diffs] master 2272131 1/7: Add lisp watchpoints, Noam Postavsky, 2016/12/02
- [Emacs-diffs] master 88fefc3 7/7: ; Merge: Lisp watchpoints (Bug#24923),
Noam Postavsky <=