}
/* Set up the buffer-local symbol SYMBOL for validity in the current buffer.
- VALCONTENTS is the contents of its value cell.
- Return the value forwarded one step past the buffer-local indicator. */
+ VALCONTENTS is the contents of its value cell,
+ which points to a struct Lisp_Buffer_Local_Value.
+
+ Return the value forwarded one step past the buffer-local stage.
+ This could be another forwarding pointer. */
static Lisp_Object
swap_in_symval_forwarding (symbol, valcontents)
Lisp_Object symbol, valcontents;
{
- /* valcontents is a pointer to a struct resembling the cons
- (REALVALUE BUFFER CURRENT-ALIST-ELEMENT . DEFAULT-VALUE)).
-
- CURRENT-ALIST-ELEMENT is a pointer to an element of BUFFER's
- local_var_alist, that being the element whose car is this
- variable. Or it can be a pointer to the
- (CURRENT-ALIST-ELEMENT . DEFAULT-VALUE), if BUFFER does not have
- an element in its alist for this variable.
-
- If the current buffer is not BUFFER, we store the current
- REALVALUE value into CURRENT-ALIST-ELEMENT, then find the
- appropriate alist element for the buffer now current and set up
- CURRENT-ALIST-ELEMENT. Then we set REALVALUE out of that
- element, and store into BUFFER.
-
- Note that REALVALUE can be a forwarding pointer. */
-
register Lisp_Object tem1;
tem1 = XBUFFER_LOCAL_VALUE (valcontents)->buffer;
- if (NILP (tem1) || current_buffer != XBUFFER (tem1)
- || !EQ (selected_frame, XBUFFER_LOCAL_VALUE (valcontents)->frame))
+ if (NILP (tem1)
+ || current_buffer != XBUFFER (tem1)
+ || (XBUFFER_LOCAL_VALUE (valcontents)->check_frame
+ && ! EQ (selected_frame, XBUFFER_LOCAL_VALUE (valcontents)->frame)))
{
+ /* Unload the previously loaded binding. */
tem1 = XCAR (XBUFFER_LOCAL_VALUE (valcontents)->cdr);
Fsetcdr (tem1,
do_symval_forwarding (XBUFFER_LOCAL_VALUE (valcontents)->realvalue));
+ /* Choose the new binding. */
tem1 = assq_no_quit (symbol, current_buffer->local_var_alist);
XBUFFER_LOCAL_VALUE (valcontents)->found_for_frame = 0;
XBUFFER_LOCAL_VALUE (valcontents)->found_for_buffer = 0;
else
XBUFFER_LOCAL_VALUE (valcontents)->found_for_buffer = 1;
+ /* Load the new binding. */
XCAR (XBUFFER_LOCAL_VALUE (valcontents)->cdr) = tem1;
XSETBUFFER (XBUFFER_LOCAL_VALUE (valcontents)->buffer, current_buffer);
XBUFFER_LOCAL_VALUE (valcontents)->frame = selected_frame;
else if (BUFFER_LOCAL_VALUEP (valcontents)
|| SOME_BUFFER_LOCAL_VALUEP (valcontents))
{
- /* valcontents is actually a pointer to a struct resembling a cons,
- with contents something like:
- (REALVALUE BUFFER CURRENT-ALIST-ELEMENT . DEFAULT-VALUE).
-
- BUFFER is the last buffer for which this symbol's value was
- made up to date.
-
- CURRENT-ALIST-ELEMENT is a pointer to an element of BUFFER's
- local_var_alist, that being the element whose car is this
- variable. Or it can be a pointer to the
- (CURRENT-ALIST-ELEMENT . DEFAULT-VALUE), if BUFFER does not
- have an element in its alist for this variable (that is, if
- BUFFER sees the default value of this variable).
-
- If we want to examine or set the value and BUFFER is current,
- we just examine or set REALVALUE. If BUFFER is not current, we
- store the current REALVALUE value into CURRENT-ALIST-ELEMENT,
- then find the appropriate alist element for the buffer now
- current and set up CURRENT-ALIST-ELEMENT. Then we set
- REALVALUE out of that element, and store into BUFFER.
-
- If we are setting the variable and the current buffer does
- not have an alist entry for this variable, an alist entry is
- created.
-
- Note that REALVALUE can be a forwarding pointer. Each time
- it is examined or set, forwarding must be done. */
-
- /* What value are we caching right now? */
+ /* valcontents is a struct Lisp_Buffer_Local_Value. */
+
+ /* What binding is loaded right now? */
current_alist_element
= XCAR (XBUFFER_LOCAL_VALUE (valcontents)->cdr);
/* If the current buffer is not the buffer whose binding is
- currently cached, or if it's a Lisp_Buffer_Local_Value and
- we're looking at the default value, the cache is invalid; we
- need to write it out, and find the new CURRENT-ALIST-ELEMENT. */
- if (XBUFFER_LOCAL_VALUE (valcontents)->found_for_frame
- ? !EQ (selected_frame, XBUFFER_LOCAL_VALUE (valcontents)->frame)
- : (buf != XBUFFER (XBUFFER_LOCAL_VALUE (valcontents)->buffer)
- || (BUFFER_LOCAL_VALUEP (valcontents)
- && EQ (XCAR (current_alist_element),
- current_alist_element))))
+ loaded, or if there may be frame-local bindings and the frame
+ isn't the right one, or if it's a Lisp_Buffer_Local_Value and
+ the default binding is loaded, the loaded binding may be the
+ wrong one. */
+ if (buf != XBUFFER (XBUFFER_LOCAL_VALUE (valcontents)->buffer)
+ || (XBUFFER_LOCAL_VALUE (valcontents)->check_frame
+ && !EQ (selected_frame, XBUFFER_LOCAL_VALUE (valcontents)->frame))
+ || (BUFFER_LOCAL_VALUEP (valcontents)
+ && EQ (XCAR (current_alist_element),
+ current_alist_element)))
{
- /* Write out the cached value for the old buffer; copy it
- back to its alist element. This works if the current
- buffer only sees the default value, too. */
+ /* The currently loaded binding is not necessarily valid.
+ We need to unload it, and choose a new binding. */
+
+ /* Write out `realvalue' to the old loaded binding. */
Fsetcdr (current_alist_element,
do_symval_forwarding (XBUFFER_LOCAL_VALUE (valcontents)->realvalue));
- /* Find the new value for CURRENT-ALIST-ELEMENT. */
+ /* Find the new binding. */
tem1 = Fassq (symbol, buf->local_var_alist);
XBUFFER_LOCAL_VALUE (valcontents)->found_for_buffer = 1;
XBUFFER_LOCAL_VALUE (valcontents)->found_for_frame = 0;
and we're not within a let that was made for this buffer,
create a new buffer-local binding for the variable.
That means, give this buffer a new assoc for a local value
- and set CURRENT-ALIST-ELEMENT to point to that. */
+ and load that binding. */
else
{
tem1 = Fcons (symbol, Fcdr (current_alist_element));
}
}
- /* Cache the new buffer's assoc in CURRENT-ALIST-ELEMENT. */
+ /* Record which binding is now loaded. */
XCAR (XBUFFER_LOCAL_VALUE (valcontents)->cdr)
= tem1;
- /* Set BUFFER and FRAME for binding now loaded. */
+ /* Set `buffer' and `frame' slots for thebinding now loaded. */
XSETBUFFER (XBUFFER_LOCAL_VALUE (valcontents)->buffer, buf);
XBUFFER_LOCAL_VALUE (valcontents)->frame = selected_frame;
}
{
/* If var is set up for a buffer that lacks a local value for it,
the current value is nominally the default value.
- But the current value slot may be more up to date, since
+ But the `realvalue' slot may be more up to date, since
ordinary setq stores just that slot. So use that. */
Lisp_Object current_alist_element, alist_element_car;
current_alist_element
&& !SOME_BUFFER_LOCAL_VALUEP (valcontents))
return Fset (symbol, value);
- /* Store new value into the DEFAULT-VALUE slot */
+ /* Store new value into the DEFAULT-VALUE slot. */
XCDR (XBUFFER_LOCAL_VALUE (valcontents)->cdr) = value;
- /* If that slot is current, we must set the REALVALUE slot too */
+ /* If the default binding is now loaded, set the REALVALUE slot too. */
current_alist_element
= XCAR (XBUFFER_LOCAL_VALUE (valcontents)->cdr);
alist_element_buffer = Fcar (current_alist_element);
DEFUN ("make-variable-buffer-local", Fmake_variable_buffer_local, Smake_variable_buffer_local,
1, 1, "vMake Variable Buffer Local: ",
- "Make VARIABLE have a separate value for each buffer.\n\
-At any time, the value for the current buffer is in effect.\n\
-There is also a default value which is seen in any buffer which has not yet\n\
-set its own value.\n\
-Using `set' or `setq' to set the variable causes it to have a separate value\n\
-for the current buffer if it was previously using the default value.\n\
+ "Make VARIABLE become buffer-local whenever it is set.\n\
+At any time, the value for the current buffer is in effect,\n\
+unless the variable has never been set in this buffer,\n\
+in which case the default value is in effect.\n\
+Note that binding the variable with `let', or setting it while\n\
+a `let'-style binding made in this buffer is in effect,\n\
+does not make the variable buffer-local.\n\
+\n\
The function `default-value' gets the default value and `set-default' sets it.")
(variable)
register Lisp_Object variable;
XBUFFER_LOCAL_VALUE (newval)->realvalue = XSYMBOL (variable)->value;
XBUFFER_LOCAL_VALUE (newval)->buffer = Fcurrent_buffer ();
XBUFFER_LOCAL_VALUE (newval)->frame = Qnil;
- XBUFFER_LOCAL_VALUE (newval)->found_for_buffer = 1;
+ XBUFFER_LOCAL_VALUE (newval)->found_for_buffer = 0;
XBUFFER_LOCAL_VALUE (newval)->found_for_frame = 0;
XBUFFER_LOCAL_VALUE (newval)->check_frame = 0;
XBUFFER_LOCAL_VALUE (newval)->cdr = tem;
Fset (variable, (EQ (tem, Qt) ? Fsymbol_value (variable) : Qunbound));
return variable;
}
- /* Make sure symbol is set up to hold per-buffer values */
+ /* Make sure symbol is set up to hold per-buffer values. */
if (!SOME_BUFFER_LOCAL_VALUEP (valcontents))
{
Lisp_Object newval;
XBUFFER_LOCAL_VALUE (newval)->cdr = tem;
XSYMBOL (variable)->value = newval;
}
- /* Make sure this buffer has its own value of symbol */
+ /* Make sure this buffer has its own value of symbol. */
tem = Fassq (variable, current_buffer->local_var_alist);
if (NILP (tem))
{
current_buffer->local_var_alist);
/* Make sure symbol does not think it is set up for this buffer;
- force it to look once again for this buffer's value */
+ force it to look once again for this buffer's value. */
{
Lisp_Object *pvalbuf;
}
}
- /* If the symbol forwards into a C variable, then swap in the
- variable for this buffer immediately. If C code modifies the
- variable before we swap in, then that new value will clobber the
- default value the next time we swap. */
+ /* If the symbol forwards into a C variable, then load the binding
+ for this buffer now. If C code modifies the variable before we
+ load the binding in, then that new value will clobber the default
+ binding the next time we unload it. */
valcontents = XBUFFER_LOCAL_VALUE (XSYMBOL (variable)->value)->realvalue;
if (INTFWDP (valcontents) || BOOLFWDP (valcontents) || OBJFWDP (valcontents))
swap_in_symval_forwarding (variable, XSYMBOL (variable)->value);
&& !SOME_BUFFER_LOCAL_VALUEP (valcontents))
return variable;
- /* Get rid of this buffer's alist element, if any */
+ /* Get rid of this buffer's alist element, if any. */
tem = Fassq (variable, current_buffer->local_var_alist);
if (!NILP (tem))
current_buffer->local_var_alist
= Fdelq (tem, current_buffer->local_var_alist);
- /* If the symbol is set up for the current buffer, recompute its
- value. We have to do it now, or else forwarded objects won't
- work right. */
+ /* If the symbol is set up with the current buffer's binding
+ loaded, recompute its value. We have to do it now, or else
+ forwarded objects won't work right. */
{
Lisp_Object *pvalbuf;
valcontents = XSYMBOL (variable)->value;
if (BUFFER_LOCAL_VALUEP (valcontents)
|| SOME_BUFFER_LOCAL_VALUEP (valcontents))
- return variable;
+ {
+ XBUFFER_LOCAL_VALUE (valcontents)->check_frame = 1;
+ return variable;
+ }
if (EQ (valcontents, Qunbound))
XSYMBOL (variable)->value = Qnil;
projects / emacs.git / commitdiff