Commit 0f25ecc6 authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

Support print-circle and related features.

(Vprint_gensym_alist): Removed.
(Vprint_circle, Vprint_continuous_numbering, print_number_index
Vprint_number_table): New variables.
(PRINT_NUMBER_OBJECT, PRINT_NUMBER_STATUS): New macros.
(PRINTPREPARE, PRINTFINISH): Don't set Vprint_gensym_alist.
(print, print_preprocess, print_preprocess_string, print_object):
New/modified functions with print-circle feature.  Use
Vprint_number_table instead of Vprint_gensym_alist for print-gensym.
(syms_of_print): Defined new Lisp variables `print-circle',
`print-continuous-numbering', `print-number-table'.
parent 701552dd
......@@ -143,17 +143,33 @@ Lisp_Object Qprint_escape_multibyte, Qprint_escape_nonascii;
int print_quoted;
/* Non-nil means print #: before uninterned symbols.
Neither t nor nil means so that and don't clear Vprint_gensym_alist
on entry to and exit from print functions. */
/* Non-nil means print #: before uninterned symbols. */
Lisp_Object Vprint_gensym;
/* Association list of certain objects that are `eq' in the form being
printed and which should be `eq' when read back in, using the #n=object
and #n# reader forms. Each element has the form (object . n). */
/* Non-nil means print recursive structures using #n= and #n# syntax. */
Lisp_Object Vprint_gensym_alist;
Lisp_Object Vprint_circle;
/* Non-nil means keep continuous number for #n= and #n# syntax
between several print functions. */
Lisp_Object Vprint_continuous_numbering;
/* Vprint_number_table is a vector like [OBJ1 STAT1 OBJ2 STAT2 ...],
where OBJn are objects going to be printed, and STATn are their status,
which may be different meanings during process. See the comments of
the functions print and print_preprocess for details.
print_number_index keeps the last position the next object should be added,
twice of which is the actual vector position in Vprint_number_table. */
int print_number_index;
Lisp_Object Vprint_number_table;
/* PRINT_NUMBER_OBJECT returns the I'th object in Vprint_number_table TABLE.
PRINT_NUMBER_STATUS returns the status of the I'th object in TABLE.
See the comment of the variable Vprint_number_table. */
#define PRINT_NUMBER_OBJECT(table,i) XVECTOR ((table))->contents[(i) * 2]
#define PRINT_NUMBER_STATUS(table,i) XVECTOR ((table))->contents[(i) * 2 + 1]
/* Nonzero means print newline to stdout before next minibuffer message.
Defined in xdisp.c */
......@@ -237,9 +253,7 @@ void print_interval ();
print_buffer_pos_byte = 0; \
} \
if (EQ (printcharfun, Qt)) \
setup_echo_area_for_printing (multibyte); \
if (!CONSP (Vprint_gensym)) \
Vprint_gensym_alist = Qnil
setup_echo_area_for_printing (multibyte);
#define PRINTFINISH \
if (NILP (printcharfun)) \
......@@ -272,9 +286,7 @@ void print_interval ();
old_point_byte + (old_point_byte >= start_point_byte \
? PT_BYTE - start_point_byte : 0)); \
if (old != current_buffer) \
set_buffer_internal (old); \
if (!CONSP (Vprint_gensym)) \
Vprint_gensym_alist = Qnil
set_buffer_internal (old);
#define PRINTCHAR(ch) printchar (ch, printcharfun)
......@@ -664,6 +676,11 @@ buffer and calling the hook. It gets one argument, the buffer to display.")
static void print ();
static void print_preprocess ();
#ifdef USE_TEXT_PROPERTIES
static void print_preprocess_string ();
#endif /* USE_TEXT_PROPERTIES */
static void print_object ();
DEFUN ("terpri", Fterpri, Sterpri, 0, 1, 0,
"Output a newline to stream PRINTCHARFUN.\n\
......@@ -697,7 +714,6 @@ Output stream is PRINTCHARFUN, or value of `standard-output' (which see).")
if (NILP (printcharfun))
printcharfun = Vstandard_output;
PRINTPREPARE;
print_depth = 0;
print (object, printcharfun, 1);
PRINTFINISH;
return object;
......@@ -727,7 +743,6 @@ second argument NOESCAPE is non-nil.")
printcharfun = Vprin1_to_string_buffer;
PRINTPREPARE;
print_depth = 0;
print (object, printcharfun, NILP (noescape));
/* Make Vprin1_to_string_buffer be the default buffer after PRINTFINSH */
PRINTFINISH;
......@@ -756,7 +771,6 @@ Output stream is PRINTCHARFUN, or value of standard-output (which see).")
if (NILP (printcharfun))
printcharfun = Vstandard_output;
PRINTPREPARE;
print_depth = 0;
print (object, printcharfun, 0);
PRINTFINISH;
return object;
......@@ -781,7 +795,6 @@ Output stream is PRINTCHARFUN, or value of `standard-output' (which see).")
printcharfun = Vstandard_output;
GCPRO1 (object);
PRINTPREPARE;
print_depth = 0;
PRINTCHAR ('\n');
print (object, printcharfun, 1);
PRINTCHAR ('\n');
......@@ -1048,27 +1061,182 @@ print (obj, printcharfun, escapeflag)
register Lisp_Object printcharfun;
int escapeflag;
{
char buf[30];
print_depth = 0;
QUIT;
/* Reset print_number_index and Vprint_number_table only when
the variable Vprint_continuous_numbering is nil. Otherwise,
the values of these variables will be kept between several
print functions. */
if (NILP (Vprint_continuous_numbering))
{
print_number_index = 0;
Vprint_number_table = Qnil;
}
#if 1 /* I'm not sure this is really worth doing. */
/* Detect circularities and truncate them.
No need to offer any alternative--this is better than an error. */
if (CONSP (obj) || VECTORP (obj) || COMPILEDP (obj))
/* Construct Vprint_number_table for print-gensym and print-circle. */
if (!NILP (Vprint_gensym) || !NILP (Vprint_circle))
{
int i;
for (i = 0; i < print_depth; i++)
if (EQ (obj, being_printed[i]))
int i, index = 0;
/* Construct Vprint_number_table. */
print_preprocess (obj);
/* Remove unnecessary objects, which appear only once in OBJ;
that is, whose status is Qnil. */
for (i = 0; i < print_number_index; i++)
if (!NILP (PRINT_NUMBER_STATUS (Vprint_number_table, i)))
{
PRINT_NUMBER_OBJECT (Vprint_number_table, index)
= PRINT_NUMBER_OBJECT (Vprint_number_table, i);
/* Reset the status field for the next print step. Now this
field means whether the object has already been printed. */
PRINT_NUMBER_STATUS (Vprint_number_table, index) = Qnil;
index++;
}
print_number_index = index;
}
print_object (obj, printcharfun, escapeflag);
}
/* Construct Vprint_number_table according to the structure of OBJ.
OBJ itself and all its elements will be added to Vprint_number_table
recursively if it is a list, vector, compiled function, char-table,
string (its text properties will be traced), or a symbol that has
no obarray (this is for the print-gensym feature).
The status fields of Vprint_number_table mean whether each object appears
more than once in OBJ: Qnil at the first time, and Qt after that . */
static void
print_preprocess (obj)
Lisp_Object obj;
{
int i, size;
loop:
if (STRINGP (obj) || CONSP (obj) || VECTORP (obj)
|| COMPILEDP (obj) || CHAR_TABLE_P (obj)
|| (! NILP (Vprint_gensym)
&& SYMBOLP (obj) && NILP (XSYMBOL (obj)->obarray)))
{
for (i = 0; i < print_number_index; i++)
if (PRINT_NUMBER_OBJECT (Vprint_number_table, i) == obj)
{
sprintf (buf, "#%d", i);
strout (buf, -1, -1, printcharfun, 0);
/* OBJ appears more than once. Let's remember that. */
PRINT_NUMBER_STATUS (Vprint_number_table, i) = Qt;
return;
}
/* OBJ is not yet recorded. Let's add to the table. */
if (print_number_index == 0)
{
/* Initialize the table. */
Vprint_number_table = Fmake_vector (make_number (40), Qnil);
}
else if (XVECTOR (Vprint_number_table)->size == print_number_index * 2)
{
/* Reallocate the table. */
int i = print_number_index * 4;
Lisp_Object old_table = Vprint_number_table;
Vprint_number_table = Fmake_vector (make_number (i), Qnil);
for (i = 0; i < print_number_index; i++)
{
PRINT_NUMBER_OBJECT (Vprint_number_table, i)
= PRINT_NUMBER_OBJECT (old_table, i);
PRINT_NUMBER_STATUS (Vprint_number_table, i)
= PRINT_NUMBER_STATUS (old_table, i);
}
}
PRINT_NUMBER_OBJECT (Vprint_number_table, print_number_index) = obj;
print_number_index++;
switch (XGCTYPE (obj))
{
case Lisp_String:
#ifdef USE_TEXT_PROPERTIES
/* A string may have text properties, which can be circular. */
traverse_intervals (XSTRING (obj)->intervals, 0, 0,
print_preprocess_string, Qnil);
#endif /* USE_TEXT_PROPERTIES */
break;
case Lisp_Cons:
print_preprocess (XCAR (obj));
obj = XCDR (obj);
goto loop;
case Lisp_Vectorlike:
size = XVECTOR (obj)->size & PSEUDOVECTOR_SIZE_MASK;
for (i = 0; i < size; i++)
print_preprocess (XVECTOR (obj)->contents[i]);
}
}
}
#ifdef USE_TEXT_PROPERTIES
static void
print_preprocess_string (interval, arg)
INTERVAL interval;
Lisp_Object arg;
{
print_preprocess (interval->plist);
}
#endif /* USE_TEXT_PROPERTIES */
static void
print_object (obj, printcharfun, escapeflag)
Lisp_Object obj;
register Lisp_Object printcharfun;
int escapeflag;
{
char buf[30];
QUIT;
/* Detect circularities and truncate them. */
if (STRINGP (obj) || CONSP (obj) || VECTORP (obj)
|| COMPILEDP (obj) || CHAR_TABLE_P (obj)
|| (! NILP (Vprint_gensym)
&& SYMBOLP (obj) && NILP (XSYMBOL (obj)->obarray)))
{
if (NILP (Vprint_circle) && NILP (Vprint_gensym))
{
/* Simple but incomplete way. */
int i;
for (i = 0; i < print_depth; i++)
if (EQ (obj, being_printed[i]))
{
sprintf (buf, "#%d", i);
strout (buf, -1, -1, printcharfun, 0);
return;
}
being_printed[print_depth] = obj;
}
else
{
/* With the print-circle feature. */
int i;
for (i = 0; i < print_number_index; i++)
if (PRINT_NUMBER_OBJECT (Vprint_number_table, i) == obj)
{
if (NILP (PRINT_NUMBER_STATUS (Vprint_number_table, i)))
{
/* Add a prefix #n= if OBJ has not yet been printed;
that is, its status field is nil. */
sprintf (buf, "#%d=", i + 1);
strout (buf, -1, -1, printcharfun, 0);
/* OBJ is going to be printed. Set the status to t. */
PRINT_NUMBER_STATUS (Vprint_number_table, i) = Qt;
break;
}
else
{
/* Just print #n# if OBJ has already been printed. */
sprintf (buf, "#%d#", i + 1);
strout (buf, -1, -1, printcharfun, 0);
return;
}
}
}
}
#endif
being_printed[print_depth] = obj;
print_depth++;
if (print_depth > PRINT_CIRCLE)
......@@ -1250,35 +1418,8 @@ print (obj, printcharfun, escapeflag)
else
confusing = 0;
/* If we print an uninterned symbol as part of a complex object and
the flag print-gensym is non-nil, prefix it with #n= to read the
object back with the #n# reader syntax later if needed. */
if (! NILP (Vprint_gensym) && NILP (XSYMBOL (obj)->obarray))
{
if (print_depth > 1)
{
Lisp_Object tem;
tem = Fassq (obj, Vprint_gensym_alist);
if (CONSP (tem))
{
PRINTCHAR ('#');
print (XCDR (tem), printcharfun, escapeflag);
PRINTCHAR ('#');
break;
}
else
{
if (CONSP (Vprint_gensym_alist))
XSETFASTINT (tem, XFASTINT (XCDR (XCAR (Vprint_gensym_alist))) + 1);
else
XSETFASTINT (tem, 1);
Vprint_gensym_alist = Fcons (Fcons (obj, tem), Vprint_gensym_alist);
PRINTCHAR ('#');
print (tem, printcharfun, escapeflag);
PRINTCHAR ('=');
}
}
PRINTCHAR ('#');
PRINTCHAR (':');
}
......@@ -1320,14 +1461,14 @@ print (obj, printcharfun, escapeflag)
&& (EQ (XCAR (obj), Qquote)))
{
PRINTCHAR ('\'');
print (XCAR (XCDR (obj)), printcharfun, escapeflag);
print_object (XCAR (XCDR (obj)), printcharfun, escapeflag);
}
else if (print_quoted && CONSP (XCDR (obj)) && NILP (XCDR (XCDR (obj)))
&& (EQ (XCAR (obj), Qfunction)))
{
PRINTCHAR ('#');
PRINTCHAR ('\'');
print (XCAR (XCDR (obj)), printcharfun, escapeflag);
print_object (XCAR (XCDR (obj)), printcharfun, escapeflag);
}
else if (print_quoted && CONSP (XCDR (obj)) && NILP (XCDR (XCDR (obj)))
&& ((EQ (XCAR (obj), Qbackquote)
......@@ -1335,8 +1476,8 @@ print (obj, printcharfun, escapeflag)
|| EQ (XCAR (obj), Qcomma_at)
|| EQ (XCAR (obj), Qcomma_dot))))
{
print (XCAR (obj), printcharfun, 0);
print (XCAR (XCDR (obj)), printcharfun, escapeflag);
print_object (XCAR (obj), printcharfun, 0);
print_object (XCAR (XCDR (obj)), printcharfun, escapeflag);
}
else
{
......@@ -1351,21 +1492,47 @@ print (obj, printcharfun, escapeflag)
while (CONSP (obj))
{
/* Detect circular list. */
if (i != 0 && EQ (obj, halftail))
if (NILP (Vprint_circle))
{
sprintf (buf, " . #%d", i / 2);
strout (buf, -1, -1, printcharfun, 0);
obj = Qnil;
break;
/* Simple but imcomplete way. */
if (i != 0 && EQ (obj, halftail))
{
sprintf (buf, " . #%d", i / 2);
strout (buf, -1, -1, printcharfun, 0);
goto end_of_list;
}
}
else
{
/* With the print-circle feature. */
if (i != 0)
{
int i;
for (i = 0; i < print_number_index; i++)
if (PRINT_NUMBER_OBJECT (Vprint_number_table, i) == obj)
{
if (NILP (PRINT_NUMBER_STATUS (Vprint_number_table, i)))
{
strout (" . ", 3, 3, printcharfun, 0);
print_object (obj, printcharfun, escapeflag);
}
else
{
sprintf (buf, " . #%d#", i + 1);
strout (buf, -1, -1, printcharfun, 0);
}
goto end_of_list;
}
}
}
if (i++)
PRINTCHAR (' ');
if (print_length && i > print_length)
{
strout ("...", 3, 3, printcharfun, 0);
break;
goto end_of_list;
}
print (XCAR (obj), printcharfun, escapeflag);
print_object (XCAR (obj), printcharfun, escapeflag);
obj = XCDR (obj);
if (!(i & 1))
halftail = XCDR (halftail);
......@@ -1374,8 +1541,9 @@ print (obj, printcharfun, escapeflag)
if (!NILP (obj))
{
strout (" . ", 3, 3, printcharfun, 0);
print (obj, printcharfun, escapeflag);
print_object (obj, printcharfun, escapeflag);
}
end_of_list:
PRINTCHAR (')');
}
break;
......@@ -1539,7 +1707,7 @@ print (obj, printcharfun, escapeflag)
{
if (i) PRINTCHAR (' ');
tem = XVECTOR (obj)->contents[i];
print (tem, printcharfun, escapeflag);
print_object (tem, printcharfun, escapeflag);
}
}
PRINTCHAR (']');
......@@ -1601,22 +1769,22 @@ print (obj, printcharfun, escapeflag)
case Lisp_Misc_Objfwd:
strout ("#<objfwd to ", -1, -1, printcharfun, 0);
print (*XOBJFWD (obj)->objvar, printcharfun, escapeflag);
print_object (*XOBJFWD (obj)->objvar, printcharfun, escapeflag);
PRINTCHAR ('>');
break;
case Lisp_Misc_Buffer_Objfwd:
strout ("#<buffer_objfwd to ", -1, -1, printcharfun, 0);
print (*(Lisp_Object *)((char *)current_buffer
+ XBUFFER_OBJFWD (obj)->offset),
print_object (*(Lisp_Object *)((char *)current_buffer
+ XBUFFER_OBJFWD (obj)->offset),
printcharfun, escapeflag);
PRINTCHAR ('>');
break;
case Lisp_Misc_Kboard_Objfwd:
strout ("#<kboard_objfwd to ", -1, -1, printcharfun, 0);
print (*(Lisp_Object *)((char *) current_kboard
+ XKBOARD_OBJFWD (obj)->offset),
print_object (*(Lisp_Object *)((char *) current_kboard
+ XKBOARD_OBJFWD (obj)->offset),
printcharfun, escapeflag);
PRINTCHAR ('>');
break;
......@@ -1628,28 +1796,29 @@ print (obj, printcharfun, escapeflag)
strout ("#<some_buffer_local_value ", -1, -1, printcharfun, 0);
do_buffer_local:
strout ("[realvalue] ", -1, -1, printcharfun, 0);
print (XBUFFER_LOCAL_VALUE (obj)->realvalue, printcharfun, escapeflag);
print_object (XBUFFER_LOCAL_VALUE (obj)->realvalue,
printcharfun, escapeflag);
if (XBUFFER_LOCAL_VALUE (obj)->found_for_buffer)
strout ("[local in buffer] ", -1, -1, printcharfun, 0);
else
strout ("[buffer] ", -1, -1, printcharfun, 0);
print (XBUFFER_LOCAL_VALUE (obj)->buffer,
printcharfun, escapeflag);
print_object (XBUFFER_LOCAL_VALUE (obj)->buffer,
printcharfun, escapeflag);
if (XBUFFER_LOCAL_VALUE (obj)->check_frame)
{
if (XBUFFER_LOCAL_VALUE (obj)->found_for_frame)
strout ("[local in frame] ", -1, -1, printcharfun, 0);
else
strout ("[frame] ", -1, -1, printcharfun, 0);
print (XBUFFER_LOCAL_VALUE (obj)->frame,
printcharfun, escapeflag);
print_object (XBUFFER_LOCAL_VALUE (obj)->frame,
printcharfun, escapeflag);
}
strout ("[alist-elt] ", -1, -1, printcharfun, 0);
print (XCONS (XBUFFER_LOCAL_VALUE (obj)->cdr)->car,
printcharfun, escapeflag);
print_object (XCONS (XBUFFER_LOCAL_VALUE (obj)->cdr)->car,
printcharfun, escapeflag);
strout ("[default-value] ", -1, -1, printcharfun, 0);
print (XCONS (XBUFFER_LOCAL_VALUE (obj)->cdr)->cdr,
printcharfun, escapeflag);
print_object (XCONS (XBUFFER_LOCAL_VALUE (obj)->cdr)->cdr,
printcharfun, escapeflag);
PRINTCHAR ('>');
break;
......@@ -1690,12 +1859,12 @@ print_interval (interval, printcharfun)
Lisp_Object printcharfun;
{
PRINTCHAR (' ');
print (make_number (interval->position), printcharfun, 1);
print_object (make_number (interval->position), printcharfun, 1);
PRINTCHAR (' ');
print (make_number (interval->position + LENGTH (interval)),
print_object (make_number (interval->position + LENGTH (interval)),
printcharfun, 1);
PRINTCHAR (' ');
print (interval->plist, printcharfun, 1);
print_object (interval->plist, printcharfun, 1);
}
#endif /* USE_TEXT_PROPERTIES */
......@@ -1773,22 +1942,35 @@ forms print in the new syntax.");
DEFVAR_LISP ("print-gensym", &Vprint_gensym,
"Non-nil means print uninterned symbols so they will read as uninterned.\n\
I.e., the value of (make-symbol \"foobar\") prints as #:foobar.\n\
When the uninterned symbol appears within a larger data structure,\n\
in addition use the #...# and #...= constructs as needed,\n\
so that multiple references to the same symbol are shared once again\n\
when the text is read back.\n\
\n\
If the value of `print-gensym' is a cons cell, then in addition refrain from\n\
clearing `print-gensym-alist' on entry to and exit from printing functions,\n\
so that the use of #...# and #...= can carry over for several separately\n\
printed objects.");
When the uninterned symbol appears within a recursive data structure\n\
and the symbol appears more than once, in addition use the #N# and #N=\n\
constructs as needed, so that multiple references to the same symbol are\n\
shared once again when the text is read back.");
Vprint_gensym = Qnil;
DEFVAR_LISP ("print-gensym-alist", &Vprint_gensym_alist,
"Association list of elements (GENSYM . N) to guide use of #N# and #N=.\n\
In each element, GENSYM is an uninterned symbol that has been associated\n\
with #N= for the specified value of N.");
Vprint_gensym_alist = Qnil;
DEFVAR_LISP ("print-circle", &Vprint_circle,
"*Non-nil means print recursive structures using #N= and #N# syntax.\n\
If nil, printing proceeds recursively and may lead to\n\
`max-lisp-eval-depth' being exceeded or an error may occur:\n\
\"Apparently circular structure being printed.\" Also see\n\
`print-length' and `print-level'.\n\
If non-nil, shared substructures anywhere in the structure are printed\n\
with `#N=' before the first occurrence (in the order of the print\n\
representation) and `#N#' in place of each subsequent occurrence,\n\
where N is a positive decimal integer.");
Vprint_circle = Qnil;
DEFVAR_LISP ("print-continuous-numbering", &Vprint_continuous_numbering,
"*Non-nil means keep numbering between several print functions.\n\
See `print-gensym' nad `print-circle'. See also `print-number-table'.");
Vprint_continuous_numbering = Qnil;
DEFVAR_LISP ("print-number-table", &Vprint_number_table,
"A vector keeping the information of the current printed object.\n\
This variable shouldn't be modified in Lisp level, but should be binded\n\
with nil using let at the same position with `print-continuous-numbering',\n\
so that the value of this variable can be freed after printing.");
Vprint_number_table = Qnil;
/* prin1_to_string_buffer initialized in init_buffer_once in buffer.c */
staticpro (&Vprin1_to_string_buffer);
......
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