From: npostavs@users.sourceforge.net
To: Eli Zaretskii <eliz@gnu.org>
Cc: 24923@debbugs.gnu.org
Subject: bug#24923: 25.1; Lisp watchpoints
Date: Sat, 19 Nov 2016 21:12:13 -0500 [thread overview]
Message-ID: <874m32lx1e.fsf@users.sourceforge.net> (raw)
In-Reply-To: <83fumvcs99.fsf@gnu.org> (Eli Zaretskii's message of "Sun, 13 Nov 2016 17:29:54 +0200")
[-- Attachment #1: Type: text/plain, Size: 449 bytes --]
Eli Zaretskii <eliz@gnu.org> writes:
>
> Our coding conventions put the logical operators at the beginning of a
> line, not at EOL.
Fixed this, and added documentation. Also, watcher functions are now
listed in describe-variable output.
Does it make sense to mention the use of the `watchers' symbol property
in the manual? Since I've added a `get-variable-watchers' it's now
possible to ignore the symbol property as an implementation detail.
[-- Attachment #2: patch --]
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From c318be2dc401d2f3b958ceb3b48e466a3019091e Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Thu, 19 Nov 2015 19:50:06 -0500
Subject: [PATCH v6 1/6] Add lisp watchpoints
This allows to call a function whenever a symbol-value is changed.
* src/lisp.h (lisp_h_SYMBOL_TRAPPED_WRITE_P):
(SYMBOL_TRAPPED_WRITE_P): New function/macro.
(lisp_h_SYMBOL_CONSTANT_P): Check for SYMBOL_NOWRITE specifically.
(enum symbol_trapped_write): New enumeration.
(struct Lisp_Symbol): Rename field constant to trapped_write.
(make_symbol_constant): New function.
* src/data.c (Fadd_variable_watcher, Fremove_variable_watcher):
(set_symbol_trapped_write, restore_symbol_trapped_write):
(harmonize_variable_watchers, notify_variable_watchers): New functions.
* src/data.c (Fset_default): Call `notify_variable_watchers' for trapped
symbols.
(set_internal): Change bool argument BIND to 3-value enum and call
`notify_variable_watchers' for trapped symbols.
* src/data.c (syms_of_data):
* src/data.c (syms_of_data):
* src/font.c (syms_of_font):
* src/lread.c (intern_sym, init_obarray):
* src/buffer.c (syms_of_buffer): Use make_symbol_constant.
* src/alloc.c (init_symbol):
* src/bytecode.c (exec_byte_code): Use SYMBOL_TRAPPED_WRITE_P.
* src/data.c (Fmake_variable_buffer_local, Fmake_local_variable):
(Fmake_variable_frame_local):
* src/eval.c (Fdefvaralias, specbind): Refer to Lisp_Symbol's
trapped_write instead of constant.
(Ffuncall): Move subr calling code into separate function.
(funcall_subr): New function.
---
src/alloc.c | 2 +-
src/buffer.c | 22 +++++--
src/bytecode.c | 4 +-
src/data.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
src/eval.c | 172 +++++++++++++++++++++++++++++--------------------------
src/font.c | 6 +-
src/lisp.h | 54 +++++++++++++++---
src/lread.c | 6 +-
8 files changed, 324 insertions(+), 119 deletions(-)
diff --git a/src/alloc.c b/src/alloc.c
index a58dc13..f373f6d 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3562,7 +3562,7 @@ 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 3d205bb..cc75cdb 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -984,9 +984,13 @@ 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)))
+ {
+ 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;
@@ -1010,7 +1014,12 @@ reset_buffer_local_variables (struct buffer *b, bool permanent_too)
|| !NILP (Fget (elt, Qpermanent_local_hook)))
newlist = Fcons (elt, newlist);
}
- XSETCDR (XCAR (tmp), Fnreverse (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. */
@@ -1018,6 +1027,11 @@ reset_buffer_local_variables (struct buffer *b, bool permanent_too)
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)
@@ -5682,7 +5696,7 @@ syms_of_buffer (void)
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 e2d8ab7..18eaf9f 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 d221db4..8954b42 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 +1251,31 @@ 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);
else
/* 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;
+
+ default: emacs_abort ();
}
maybe_set_redisplay (symbol);
- sym = XSYMBOL (symbol);
start:
switch (sym->redirect)
@@ -1386,6 +1400,111 @@ 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.
+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;
+}
+
+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);
+}
+
+\f
/* Access or set a buffer-local symbol's default value. */
/* Return the default value of SYMBOL, but don't check for voidness.
@@ -1471,16 +1590,27 @@ DEFUN ("set-default", Fset_default, Sset_default, 2, 2, 0,
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)))
+ || !EQ (value, Fsymbol_value (symbol)))
xsignal1 (Qsetting_constant, symbol);
else
/* 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 +1781,7 @@ DEFUN ("make-variable-buffer-local", Fmake_variable_buffer_local,
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 +1856,7 @@ DEFUN ("make-local-variable", Fmake_local_variable, Smake_local_variable,
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 +1968,9 @@ DEFUN ("kill-local-variable", Fkill_local_variable, Skill_local_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 +2053,7 @@ DEFUN ("make-variable-frame-local", Fmake_variable_frame_local, Smake_variable_f
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);
@@ -3471,6 +3604,8 @@ 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");
@@ -3549,6 +3684,10 @@ 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,
@@ -3727,10 +3866,18 @@ 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);
}
diff --git a/src/eval.c b/src/eval.c
index a9bad24..c5c6fa9 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -593,12 +593,12 @@ DEFUN ("defvaralias", Fdefvaralias, Sdefvaralias, 2, 3, 0,
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 @@ DEFUN ("defvaralias", Fdefvaralias, Sdefvaralias, 2, 3, 0,
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 @@ DEFUN ("defvaralias", Fdefvaralias, Sdefvaralias, 2, 3, 0,
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);
@@ -2644,9 +2647,7 @@ DEFUN ("funcall", Ffuncall, Sfuncall, 1, MANY, 0,
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;
@@ -2679,76 +2680,110 @@ DEFUN ("funcall", Ffuncall, Sfuncall, 1, MANY, 0,
fun = indirect_function (fun);
if (SUBRP (fun))
+ val = funcall_subr (XSUBR (fun), numargs, args + 1);
+ else if (COMPILEDP (fun))
+ val = funcall_lambda (fun, numargs, args + 1);
+ else
{
- if (numargs < XSUBR (fun)->min_args
- || (XSUBR (fun)->max_args >= 0 && XSUBR (fun)->max_args < numargs))
+ if (NILP (fun))
+ xsignal1 (Qvoid_function, original_fun);
+ if (!CONSP (fun))
+ xsignal1 (Qinvalid_function, original_fun);
+ funcar = XCAR (fun);
+ if (!SYMBOLP (funcar))
+ xsignal1 (Qinvalid_function, original_fun);
+ if (EQ (funcar, Qlambda)
+ || EQ (funcar, Qclosure))
+ val = funcall_lambda (fun, numargs, args + 1);
+ else if (EQ (funcar, Qautoload))
{
- XSETFASTINT (lisp_numargs, numargs);
- xsignal2 (Qwrong_number_of_arguments, original_fun, lisp_numargs);
+ Fautoload_do_load (fun, original_fun, Qnil);
+ check_cons_list ();
+ goto retry;
}
-
- else if (XSUBR (fun)->max_args == UNEVALLED)
+ else
xsignal1 (Qinvalid_function, original_fun);
+ }
+ check_cons_list ();
+ lisp_eval_depth--;
+ if (backtrace_debug_on_exit (specpdl + count))
+ val = call_debugger (list2 (Qexit, val));
+ specpdl_ptr--;
+ return val;
+}
\f
- else if (XSUBR (fun)->max_args == MANY)
- val = (XSUBR (fun)->function.aMANY) (numargs, args + 1);
+
+/* 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];
- if (XSUBR (fun)->max_args > numargs)
+ Lisp_Object *internal_args;
+ if (subr->max_args > numargs)
{
- eassert (XSUBR (fun)->max_args <= ARRAYELTS (internal_argbuf));
+ eassert (subr->max_args <= ARRAYELTS (internal_argbuf));
internal_args = internal_argbuf;
- memcpy (internal_args, args + 1, numargs * word_size);
+ memcpy (internal_args, args, numargs * word_size);
memclear (internal_args + numargs,
- (XSUBR (fun)->max_args - numargs) * word_size);
+ (subr->max_args - numargs) * word_size);
}
else
- internal_args = args + 1;
- switch (XSUBR (fun)->max_args)
+ internal_args = args;
+ switch (subr->max_args)
{
case 0:
- val = (XSUBR (fun)->function.a0 ());
- break;
+ return (subr->function.a0 ());
case 1:
- val = (XSUBR (fun)->function.a1 (internal_args[0]));
- break;
+ return (subr->function.a1 (internal_args[0]));
case 2:
- val = (XSUBR (fun)->function.a2
+ return (subr->function.a2
(internal_args[0], internal_args[1]));
- break;
case 3:
- val = (XSUBR (fun)->function.a3
+ return (subr->function.a3
(internal_args[0], internal_args[1], internal_args[2]));
- break;
case 4:
- val = (XSUBR (fun)->function.a4
+ return (subr->function.a4
(internal_args[0], internal_args[1], internal_args[2],
internal_args[3]));
- break;
case 5:
- val = (XSUBR (fun)->function.a5
+ return (subr->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
+ return (subr->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
+ 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]));
- break;
-
case 8:
- val = (XSUBR (fun)->function.a8
+ 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]));
- break;
default:
@@ -2759,36 +2794,6 @@ DEFUN ("funcall", Ffuncall, Sfuncall, 1, MANY, 0,
}
}
}
- else if (COMPILEDP (fun))
- val = funcall_lambda (fun, numargs, args + 1);
- else
- {
- if (NILP (fun))
- xsignal1 (Qvoid_function, original_fun);
- if (!CONSP (fun))
- xsignal1 (Qinvalid_function, original_fun);
- funcar = XCAR (fun);
- if (!SYMBOLP (funcar))
- xsignal1 (Qinvalid_function, original_fun);
- if (EQ (funcar, Qlambda)
- || EQ (funcar, Qclosure))
- val = funcall_lambda (fun, numargs, args + 1);
- else if (EQ (funcar, Qautoload))
- {
- Fautoload_do_load (fun, original_fun, Qnil);
- check_cons_list ();
- goto retry;
- }
- else
- xsignal1 (Qinvalid_function, original_fun);
- }
- check_cons_list ();
- lisp_eval_depth--;
- if (backtrace_debug_on_exit (specpdl + count))
- val = call_debugger (list2 (Qexit, val));
- specpdl_ptr--;
- return val;
-}
static Lisp_Object
apply_lambda (Lisp_Object fun, Lisp_Object args, ptrdiff_t count)
@@ -3158,10 +3163,10 @@ 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)
@@ -3201,7 +3206,7 @@ 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 ();
@@ -3328,14 +3333,16 @@ 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
@@ -3358,7 +3365,7 @@ 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;
}
@@ -3583,7 +3590,7 @@ 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;
@@ -3927,6 +3934,7 @@ syms_of_eval (void)
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 ce63233..3b821a4 100644
--- a/src/font.c
+++ b/src/font.c
@@ -5417,19 +5417,19 @@ syms_of_font (void)
[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 2e46592..701ee9c 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -320,7 +320,8 @@ DEFINE_GDB_SYMBOL_END (USE_LSB_TAG)
#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 @@ DEFINE_GDB_SYMBOL_END (USE_LSB_TAG)
# 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)
@@ -602,6 +604,9 @@ INLINE bool (VECTORLIKEP) (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);
+
/* Defined in emacs.c. */
#ifdef DOUG_LEA_MALLOC
@@ -632,6 +637,13 @@ INLINE bool (VECTORLIKEP) (Lisp_Object);
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 @@ INLINE bool (VECTORLIKEP) (Lisp_Object);
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)
@@ -3289,6 +3312,12 @@ 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
@@ -3397,7 +3426,13 @@ set_sub_char_table_contents (Lisp_Object table, ptrdiff_t idx, Lisp_Object val)
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 *);
@@ -3880,6 +3915,7 @@ xsignal (Lisp_Object error_symbol, Lisp_Object data)
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 58d518c..7e74703 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. */
--
2.9.3
[-- Attachment #3: patch --]
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From dda5dc2280e77c664e7f479eb9bd84e2db2024f0 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 19 Nov 2016 16:50:34 -0500
Subject: [PATCH v6 2/6] Show watchpoints when describing variables
* src/data.c (Fget_variable_watchers): New function.
* lisp/help-fns.el (describe-variable): Use it to detect watching
functions.
---
lisp/help-fns.el | 7 +++++++
src/data.c | 11 +++++++++++
2 files changed, 18 insertions(+)
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 @@ describe-variable
(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 @@ describe-variable
(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/data.c b/src/data.c
index 8954b42..911789f 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1463,6 +1463,16 @@ SYMBOL (or its aliases) are set. */)
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,
@@ -3880,4 +3890,5 @@ syms_of_data (void)
DEFSYM (Qset_default, "set-default");
defsubr (&Sadd_variable_watcher);
defsubr (&Sremove_variable_watcher);
+ defsubr (&Sget_variable_watchers);
}
--
2.9.3
[-- Attachment #4: patch --]
[-- Type: text/plain, Size: 4926 bytes --]
From 68b3861097e1b6ea8e353e89aa339a59645d6a37 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 21 Nov 2015 16:03:06 -0500
Subject: [PATCH v6 3/6] Add function to trigger debugger on variable write
* lisp/emacs-lisp/debug.el (debug-on-variable-change):
(debug--variable-list):
(cancel-debug-on-variable-change): New functions.
(debugger-setup-buffer): Add watchpoint clause.
---
lisp/emacs-lisp/debug.el | 91 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 91 insertions(+)
diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 7d27380..0fefc54 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -306,6 +306,24 @@ debugger-setup-buffer
(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 @@ debugger-list-functions
(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-entry] 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
--
2.9.3
[-- Attachment #5: patch --]
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From 5d87668684319bb165ed0f31f637c44cda5716a6 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 21 Nov 2015 17:02:42 -0500
Subject: [PATCH v6 4/6] Ensure redisplay using variable watcher
Instead of looking up the variable name in redisplay--variables when
setting.
* lisp/frame.el: Replace redisplay--variables with add-variable-watcher
calls.
* src/xdisp.c (Fset_buffer_redisplay): Rename from maybe_set_redisplay,
set the redisplay flag unconditionally.
(Vredisplay__variables): Remove it.
* src/data.c (set_internal): Remove maybe_set_redisplay call.
---
lisp/frame.el | 3 +--
src/data.c | 2 --
src/window.h | 1 -
src/xdisp.c | 17 +++++++----------
4 files changed, 8 insertions(+), 15 deletions(-)
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 @@ 'automatic-hscrolling
'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/src/data.c b/src/data.c
index 911789f..ff35315 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1275,8 +1275,6 @@ set_internal (Lisp_Object symbol, Lisp_Object newval, Lisp_Object where,
default: emacs_abort ();
}
- maybe_set_redisplay (symbol);
-
start:
switch (sym->redirect)
{
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 @@ void set_window_buffer (Lisp_Object window, Lisp_Object buffer,
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 6e8af8a..9d36ab6 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)
+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
@@ -31319,6 +31319,7 @@ syms_of_xdisp (void)
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);
@@ -31988,10 +31989,6 @@ or t (meaning all windows). */);
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
--
2.9.3
[-- Attachment #6: patch --]
[-- Type: text/plain, Size: 6296 bytes --]
From 10d324a797981a3f89e890ed3806a9f470f3b7bf Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 12 Dec 2015 23:10:15 -0500
Subject: [PATCH v6 5/6] Add tests for watchpoints
* test/src/data-tests.el (data-tests-variable-watchers):
(data-tests-local-variable-watchers): New tests.
---
test/src/data-tests.el | 115 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 115 insertions(+)
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 @@ test-bool-vector-binop
(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)))))
--
2.9.3
[-- Attachment #7: patch --]
[-- Type: text/plain, Size: 7764 bytes --]
From 984109b9b204c82ce2e6482210425a70b7b7e867 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sun, 13 Dec 2015 14:47:58 -0500
Subject: [PATCH v6 6/6] Document watchpoints
* doc/lispref/debugging.texi (Variable Debugging):
* doc/lispref/variables.texi (Watching Variables): New section.
* etc/NEWS: Add entry for watchpoints
---
doc/lispref/debugging.texi | 32 +++++++++++++++++++++++
doc/lispref/variables.texi | 63 ++++++++++++++++++++++++++++++++++++++++++++++
etc/NEWS | 5 ++++
src/data.c | 9 +++++++
4 files changed, 109 insertions(+)
diff --git a/doc/lispref/debugging.texi b/doc/lispref/debugging.texi
index 6c0908a..8cae203 100644
--- a/doc/lispref/debugging.texi
+++ b/doc/lispref/debugging.texi
@@ -69,6 +69,7 @@ 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.
@@ -290,6 +291,37 @@ Function Debugging
not currently set up to break on entry.
@end deffn
+@node Variable Debugging
+@subsection Entering the debugger when a variable is modified
+@cindex variable write debugging
+@cindex 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 quick way to find the origin of the setting.
+
+@deffn Command debug-on-variable-change variable
+This function arranges causes the debugger to be called whenever
+@var{variable} 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 @xref{Watching Variables}.
+
+@end deffn
+
+@deffn Command cancel-debug-on-variable-change &optional variable
+This function undoes the effect of @code{debug-on-variable-change} on
+@var{variable}. When called interactively, it prompts for
+@var{variable} in the minibuffer. If @var{variable} is omitted or
+@code{nil}, it cancels break-on-change for all variables. Calling
+@code{cancel-debug-on-variable-change} does nothing to a variable
+which is not currently set up to break on change.
+@end deffn
+
+
@node Explicit Debug
@subsection Explicit Entry to the Debugger
@cindex debugger, explicit entry
diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi
index 418a416..07f787c 100644
--- a/doc/lispref/variables.texi
+++ b/doc/lispref/variables.texi
@@ -34,6 +34,7 @@ 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.
@@ -765,6 +766,68 @@ Setting Variables
@end example
@end defun
+@node Watching Variables
+@section Running a function when a variable is changed.
+@cindex variable watchpoints
+
+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}.
+
+Each variable has a list of watch functions stored in its
+@code{watchers} symbol property, @xref{Symbol Properties}. However,
+for efficiency reasons, the list is only consulted if symbol is marked
+as watched. Therefore, the watch function list should only be
+manipulated by the following functions, which take care of the
+symbol's watched status in addition to the property value.
+
+@defun add-variable-watcher symbol watch-function
+This function arranges for @var{watch-function} to be called whenever
+@var{symbol} (or any of its aliases @pxref{Variable Aliases}) are
+modified.
+
+It will be called with 4 arguments: (@var{symbol} @var{newval}
+@var{operation} @var{where}).
+
+@var{symbol} is the variable being changed.
+@var{newval} is the value it will be changed to.
+@var{operation} is a symbol representing the kind of change, one of:
+`set', `let', `unlet', `makunbound', and `defvaralias'.
+@var{where} is a buffer if the buffer-local value of the variable
+being changed, nil otherwise.
+@end defun
+
+@defun remove-variable-watch symbol watch-function
+This function removes @var{watch-function} from @var{symbol}'s list of
+watchers.
+@end defun
+
+@defun get-variable-watchers symbol
+This function returns the list of active watcher functions.
+@end defun
+
+@subsection 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 the watchpoint 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 e29dfe2..fcbbb44 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -627,6 +627,11 @@ 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/src/data.c b/src/data.c
index ff35315..ef6b48b 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1428,6 +1428,15 @@ harmonize_variable_watchers (Lisp_Object alias, Lisp_Object base_variable)
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)
{
--
2.9.3
next prev parent reply other threads:[~2016-11-20 2:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-11 3:10 bug#24923: 25.1; Lisp watchpoints npostavs
2016-11-11 10:02 ` Eli Zaretskii
2016-11-12 4:34 ` npostavs
2016-11-12 7:19 ` Eli Zaretskii
2016-11-13 0:54 ` npostavs
2016-11-13 15:29 ` Eli Zaretskii
2016-11-20 2:12 ` npostavs [this message]
2016-11-20 10:49 ` Stephen Berman
2016-11-20 14:14 ` npostavs
2016-11-20 16:11 ` Eli Zaretskii
2016-11-20 19:26 ` npostavs
2016-11-20 19:36 ` Eli Zaretskii
2016-11-20 20:16 ` npostavs
2016-11-21 17:31 ` Eli Zaretskii
2016-12-03 1:47 ` npostavs
2016-12-03 3:49 ` Clément Pit--Claudel
2016-12-03 3:50 ` Clément Pit--Claudel
2016-12-03 5:01 ` Daniel Colascione
2016-12-03 14:11 ` npostavs
2016-11-20 15:58 ` Eli Zaretskii
2016-11-20 17:00 ` npostavs
2016-11-20 17:25 ` Eli Zaretskii
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