eval.c 111 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* Evaluator for GNU Emacs Lisp interpreter.
2
   Copyright (C) 1985-1987, 1993-1995, 1999-2011  Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
3 4 5

This file is part of GNU Emacs.

6
GNU Emacs is free software: you can redistribute it and/or modify
Jim Blandy's avatar
Jim Blandy committed
7
it under the terms of the GNU General Public License as published by
8 9
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Jim Blandy's avatar
Jim Blandy committed
10 11 12 13 14 15 16

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
17
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
Jim Blandy's avatar
Jim Blandy committed
18 19


20
#include <config.h>
21
#include <limits.h>
22
#include <setjmp.h>
Jim Blandy's avatar
Jim Blandy committed
23
#include "lisp.h"
24
#include "blockinput.h"
Jim Blandy's avatar
Jim Blandy committed
25
#include "commands.h"
Jim Blandy's avatar
Jim Blandy committed
26
#include "keyboard.h"
27
#include "dispextern.h"
28
#include "frame.h"		/* For XFRAME.  */
Jim Blandy's avatar
Jim Blandy committed
29

30 31 32 33
#if HAVE_X_WINDOWS
#include "xterm.h"
#endif

34 35 36 37
#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif

38 39
/* This definition is duplicated in alloc.c and keyboard.c.  */
/* Putting it in lisp.h makes cc bomb out!  */
Jim Blandy's avatar
Jim Blandy committed
40 41

struct backtrace
42 43 44
{
  struct backtrace *next;
  Lisp_Object *function;
45
  Lisp_Object *args;	/* Points to vector of args.  */
46 47 48 49 50 51 52 53 54
#define NARGS_BITS (BITS_PER_INT - 2)
  /* Let's not use size_t because we want to allow negative values (for
     UNEVALLED).  Also let's steal 2 bits so we save a word (or more for
     alignment).  In any case I doubt Emacs would survive a function call with
     more than 500M arguments.  */
  int nargs : NARGS_BITS; /* Length of vector.
			     If nargs is UNEVALLED, args points
			     to slot holding list of unevalled args.  */
  char evalargs : 1;
55
  /* Nonzero means call value of debugger when done with this operation.  */
56
  char debug_on_exit : 1;
57
};
Jim Blandy's avatar
Jim Blandy committed
58 59 60 61

struct backtrace *backtrace_list;
struct catchtag *catchlist;

62 63 64 65 66
#ifdef DEBUG_GCPRO
/* Count levels of GCPRO to detect failure to UNGCPRO.  */
int gcpro_level;
#endif

67
Lisp_Object Qautoload, Qmacro, Qexit, Qinteractive, Qcommandp, Qdefun;
68
Lisp_Object Qinhibit_quit;
Jim Blandy's avatar
Jim Blandy committed
69 70
Lisp_Object Qand_rest, Qand_optional;
Lisp_Object Qdebug_on_error;
71
Lisp_Object Qdeclare;
72 73
Lisp_Object Qinternal_interpreter_environment, Qclosure;

74
Lisp_Object Qdebug;
Jim Blandy's avatar
Jim Blandy committed
75

76 77 78
/* This holds either the symbol `run-hooks' or nil.
   It is nil at an early stage of startup, and when Emacs
   is shutting down.  */
79

Jim Blandy's avatar
Jim Blandy committed
80 81 82 83 84
Lisp_Object Vrun_hooks;

/* Non-nil means record all fset's and provide's, to be undone
   if the file being autoloaded is not fully loaded.
   They are recorded by being consed onto the front of Vautoload_queue:
85
   (FUN . ODEF) for a defun, (0 . OFEATURES) for a provide.  */
Jim Blandy's avatar
Jim Blandy committed
86 87 88 89

Lisp_Object Vautoload_queue;

/* Current number of specbindings allocated in specpdl.  */
90

91
EMACS_INT specpdl_size;
Jim Blandy's avatar
Jim Blandy committed
92 93

/* Pointer to beginning of specpdl.  */
94

Jim Blandy's avatar
Jim Blandy committed
95 96 97
struct specbinding *specpdl;

/* Pointer to first unused element in specpdl.  */
98

99
struct specbinding *specpdl_ptr;
Jim Blandy's avatar
Jim Blandy committed
100 101

/* Depth in Lisp evaluations and function calls.  */
102

103
EMACS_INT lisp_eval_depth;
Jim Blandy's avatar
Jim Blandy committed
104

105
/* The value of num_nonmacro_input_events as of the last time we
106
   started to enter the debugger.  If we decide to enter the debugger
107
   again when this is still equal to num_nonmacro_input_events, then we
108 109 110
   know that the debugger itself has an error, and we should just
   signal the error instead of entering an infinite loop of debugger
   invocations.  */
111

112
int when_entered_debugger;
Jim Blandy's avatar
Jim Blandy committed
113

114 115 116 117 118
/* The function from which the last `signal' was called.  Set in
   Fsignal.  */

Lisp_Object Vsignaling_function;

119 120 121 122 123 124
/* Set to non-zero while processing X events.  Checked in Feval to
   make sure the Lisp interpreter isn't called from a signal handler,
   which is unsafe because the interpreter isn't reentrant.  */

int handling_signal;

Stefan Monnier's avatar
Stefan Monnier committed
125
static Lisp_Object funcall_lambda (Lisp_Object, size_t, Lisp_Object *);
126
static void unwind_to_catch (struct catchtag *, Lisp_Object) NO_RETURN;
Andreas Schwab's avatar
Andreas Schwab committed
127
static int interactive_p (int);
128
static Lisp_Object apply_lambda (Lisp_Object fun, Lisp_Object args);
129

Andreas Schwab's avatar
Andreas Schwab committed
130
void
131
init_eval_once (void)
Jim Blandy's avatar
Jim Blandy committed
132 133
{
  specpdl_size = 50;
134
  specpdl = (struct specbinding *) xmalloc (specpdl_size * sizeof (struct specbinding));
135
  specpdl_ptr = specpdl;
136
  /* Don't forget to update docs (lispref node "Local Variables").  */
Stefan Monnier's avatar
Stefan Monnier committed
137
  max_specpdl_size = 1300; /* 1000 is not enough for CEDET's c-by.el.  */
138
  max_lisp_eval_depth = 600;
139 140

  Vrun_hooks = Qnil;
Jim Blandy's avatar
Jim Blandy committed
141 142
}

Andreas Schwab's avatar
Andreas Schwab committed
143
void
144
init_eval (void)
Jim Blandy's avatar
Jim Blandy committed
145 146 147 148 149 150 151 152
{
  specpdl_ptr = specpdl;
  catchlist = 0;
  handlerlist = 0;
  backtrace_list = 0;
  Vquit_flag = Qnil;
  debug_on_next_call = 0;
  lisp_eval_depth = 0;
153
#ifdef DEBUG_GCPRO
154
  gcpro_level = 0;
155
#endif
156
  /* This is less than the initial value of num_nonmacro_input_events.  */
157
  when_entered_debugger = -1;
Jim Blandy's avatar
Jim Blandy committed
158 159
}

160
/* Unwind-protect function used by call_debugger.  */
161 162

static Lisp_Object
163
restore_stack_limits (Lisp_Object data)
164 165 166
{
  max_specpdl_size = XINT (XCAR (data));
  max_lisp_eval_depth = XINT (XCDR (data));
167
  return Qnil;
168 169 170 171
}

/* Call the Lisp debugger, giving it argument ARG.  */

172
static Lisp_Object
173
call_debugger (Lisp_Object arg)
Jim Blandy's avatar
Jim Blandy committed
174
{
175
  int debug_while_redisplaying;
Juanma Barranquero's avatar
Juanma Barranquero committed
176
  int count = SPECPDL_INDEX ();
177
  Lisp_Object val;
178
  EMACS_INT old_max = max_specpdl_size;
179

180 181
  /* Temporarily bump up the stack limits,
     so the debugger won't run out of stack.  */
182

183 184 185 186 187 188 189 190 191 192 193
  max_specpdl_size += 1;
  record_unwind_protect (restore_stack_limits,
			 Fcons (make_number (old_max),
				make_number (max_lisp_eval_depth)));
  max_specpdl_size = old_max;

  if (lisp_eval_depth + 40 > max_lisp_eval_depth)
    max_lisp_eval_depth = lisp_eval_depth + 40;

  if (SPECPDL_INDEX () + 100 > max_specpdl_size)
    max_specpdl_size = SPECPDL_INDEX () + 100;
194

195
#ifdef HAVE_WINDOW_SYSTEM
196 197
  if (display_hourglass_p)
    cancel_hourglass ();
198 199
#endif

Jim Blandy's avatar
Jim Blandy committed
200
  debug_on_next_call = 0;
201
  when_entered_debugger = num_nonmacro_input_events;
202 203 204 205 206

  /* Resetting redisplaying_p to 0 makes sure that debug output is
     displayed if the debugger is invoked during redisplay.  */
  debug_while_redisplaying = redisplaying_p;
  redisplaying_p = 0;
207 208
  specbind (intern ("debugger-may-continue"),
	    debug_while_redisplaying ? Qnil : Qt);
209
  specbind (Qinhibit_redisplay, Qnil);
210
  specbind (Qdebug_on_error, Qnil);
211 212 213

#if 0 /* Binding this prevents execution of Lisp code during
	 redisplay, which necessarily leads to display problems.  */
214
  specbind (Qinhibit_eval_during_redisplay, Qt);
215
#endif
216

217 218 219 220
  val = apply1 (Vdebugger, arg);

  /* Interrupting redisplay and resuming it later is not safe under
     all circumstances.  So, when the debugger returns, abort the
221
     interrupted redisplay by going back to the top-level.  */
222 223 224
  if (debug_while_redisplaying)
    Ftop_level ();

225
  return unbind_to (count, val);
Jim Blandy's avatar
Jim Blandy committed
226 227
}

228
static void
229
do_debug_on_call (Lisp_Object code)
Jim Blandy's avatar
Jim Blandy committed
230 231 232 233 234 235 236 237 238 239 240
{
  debug_on_next_call = 0;
  backtrace_list->debug_on_exit = 1;
  call_debugger (Fcons (code, Qnil));
}

/* NOTE!!! Every function that can call EVAL must protect its args
   and temporaries from garbage collection while it needs them.
   The definition of `For' shows what you have to do.  */

DEFUN ("or", For, Sor, 0, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
241 242 243
       doc: /* Eval args until one of them yields non-nil, then return that value.
The remaining args are not evalled at all.
If all args return nil, return nil.
Juanma Barranquero's avatar
Juanma Barranquero committed
244
usage: (or CONDITIONS...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
245
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
246
{
247
  register Lisp_Object val = Qnil;
Jim Blandy's avatar
Jim Blandy committed
248 249
  struct gcpro gcpro1;

250
  GCPRO1 (args);
Jim Blandy's avatar
Jim Blandy committed
251

252
  while (CONSP (args))
Jim Blandy's avatar
Jim Blandy committed
253
    {
254
      val = eval_sub (XCAR (args));
Jim Blandy's avatar
Jim Blandy committed
255
      if (!NILP (val))
Jim Blandy's avatar
Jim Blandy committed
256
	break;
257
      args = XCDR (args);
Jim Blandy's avatar
Jim Blandy committed
258 259 260 261 262 263 264
    }

  UNGCPRO;
  return val;
}

DEFUN ("and", Fand, Sand, 0, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
265
       doc: /* Eval args until one of them yields nil, then return nil.
Pavel Janík's avatar
Pavel Janík committed
266 267
The remaining args are not evalled at all.
If no arg yields nil, return the last arg's value.
Juanma Barranquero's avatar
Juanma Barranquero committed
268
usage: (and CONDITIONS...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
269
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
270
{
271
  register Lisp_Object val = Qt;
Jim Blandy's avatar
Jim Blandy committed
272 273
  struct gcpro gcpro1;

274
  GCPRO1 (args);
Jim Blandy's avatar
Jim Blandy committed
275

276
  while (CONSP (args))
Jim Blandy's avatar
Jim Blandy committed
277
    {
278
      val = eval_sub (XCAR (args));
Jim Blandy's avatar
Jim Blandy committed
279
      if (NILP (val))
Jim Blandy's avatar
Jim Blandy committed
280
	break;
281
      args = XCDR (args);
Jim Blandy's avatar
Jim Blandy committed
282 283 284 285 286 287 288
    }

  UNGCPRO;
  return val;
}

DEFUN ("if", Fif, Sif, 2, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
289
       doc: /* If COND yields non-nil, do THEN, else do ELSE...
Pavel Janík's avatar
Pavel Janík committed
290 291 292
Returns the value of THEN or the value of the last of the ELSE's.
THEN must be one expression, but ELSE... can be zero or more expressions.
If COND yields nil, and there are no ELSE's, the value is nil.
293
usage: (if COND THEN ELSE...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
294
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
295 296 297 298 299
{
  register Lisp_Object cond;
  struct gcpro gcpro1;

  GCPRO1 (args);
300
  cond = eval_sub (Fcar (args));
Jim Blandy's avatar
Jim Blandy committed
301 302
  UNGCPRO;

Jim Blandy's avatar
Jim Blandy committed
303
  if (!NILP (cond))
304
    return eval_sub (Fcar (Fcdr (args)));
Jim Blandy's avatar
Jim Blandy committed
305 306 307 308
  return Fprogn (Fcdr (Fcdr (args)));
}

DEFUN ("cond", Fcond, Scond, 0, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
309 310 311 312 313 314 315 316
       doc: /* Try each clause until one succeeds.
Each clause looks like (CONDITION BODY...).  CONDITION is evaluated
and, if the value is non-nil, this clause succeeds:
then the expressions in BODY are evaluated and the last one's
value is the value of the cond-form.
If no clause succeeds, cond returns nil.
If a clause has one element, as in (CONDITION),
CONDITION's value if non-nil is returned from the cond-form.
317
usage: (cond CLAUSES...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
318
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
319 320 321 322 323 324
{
  register Lisp_Object clause, val;
  struct gcpro gcpro1;

  val = Qnil;
  GCPRO1 (args);
Jim Blandy's avatar
Jim Blandy committed
325
  while (!NILP (args))
Jim Blandy's avatar
Jim Blandy committed
326 327
    {
      clause = Fcar (args);
328
      val = eval_sub (Fcar (clause));
Jim Blandy's avatar
Jim Blandy committed
329
      if (!NILP (val))
Jim Blandy's avatar
Jim Blandy committed
330
	{
331 332
	  if (!EQ (XCDR (clause), Qnil))
	    val = Fprogn (XCDR (clause));
Jim Blandy's avatar
Jim Blandy committed
333 334
	  break;
	}
335
      args = XCDR (args);
Jim Blandy's avatar
Jim Blandy committed
336 337 338 339 340 341 342
    }
  UNGCPRO;

  return val;
}

DEFUN ("progn", Fprogn, Sprogn, 0, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
343
       doc: /* Eval BODY forms sequentially and return value of last one.
Juanma Barranquero's avatar
Juanma Barranquero committed
344
usage: (progn BODY...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
345
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
346
{
347
  register Lisp_Object val = Qnil;
Jim Blandy's avatar
Jim Blandy committed
348 349
  struct gcpro gcpro1;

350
  GCPRO1 (args);
Jim Blandy's avatar
Jim Blandy committed
351

352
  while (CONSP (args))
Jim Blandy's avatar
Jim Blandy committed
353
    {
354
      val = eval_sub (XCAR (args));
355
      args = XCDR (args);
Jim Blandy's avatar
Jim Blandy committed
356 357 358 359 360 361 362
    }

  UNGCPRO;
  return val;
}

DEFUN ("prog1", Fprog1, Sprog1, 1, UNEVALLED, 0,
363
       doc: /* Eval FIRST and BODY sequentially; return value from FIRST.
Pavel Janík's avatar
Pavel Janík committed
364 365
The value of FIRST is saved during the evaluation of the remaining args,
whose values are discarded.
366
usage: (prog1 FIRST BODY...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
367
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
368 369 370 371 372 373
{
  Lisp_Object val;
  register Lisp_Object args_left;
  struct gcpro gcpro1, gcpro2;
  register int argnum = 0;

374
  if (NILP (args))
Jim Blandy's avatar
Jim Blandy committed
375 376 377 378 379 380 381 382
    return Qnil;

  args_left = args;
  val = Qnil;
  GCPRO2 (args, val);

  do
    {
383
      Lisp_Object tem = eval_sub (XCAR (args_left));
Jim Blandy's avatar
Jim Blandy committed
384
      if (!(argnum++))
385 386
	val = tem;
      args_left = XCDR (args_left);
Jim Blandy's avatar
Jim Blandy committed
387
    }
388
  while (CONSP (args_left));
Jim Blandy's avatar
Jim Blandy committed
389 390 391 392 393 394

  UNGCPRO;
  return val;
}

DEFUN ("prog2", Fprog2, Sprog2, 2, UNEVALLED, 0,
395
       doc: /* Eval FORM1, FORM2 and BODY sequentially; return value from FORM2.
396 397 398
The value of FORM2 is saved during the evaluation of the
remaining args, whose values are discarded.
usage: (prog2 FORM1 FORM2 BODY...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
399
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
400 401 402 403 404 405 406 407
{
  Lisp_Object val;
  register Lisp_Object args_left;
  struct gcpro gcpro1, gcpro2;
  register int argnum = -1;

  val = Qnil;

Richard M. Stallman's avatar
Richard M. Stallman committed
408
  if (NILP (args))
Jim Blandy's avatar
Jim Blandy committed
409 410 411 412 413 414 415 416
    return Qnil;

  args_left = args;
  val = Qnil;
  GCPRO2 (args, val);

  do
    {
417
      Lisp_Object tem = eval_sub (XCAR (args_left));
Jim Blandy's avatar
Jim Blandy committed
418
      if (!(argnum++))
419 420
	val = tem;
      args_left = XCDR (args_left);
Jim Blandy's avatar
Jim Blandy committed
421
    }
422
  while (CONSP (args_left));
Jim Blandy's avatar
Jim Blandy committed
423 424 425 426 427 428

  UNGCPRO;
  return val;
}

DEFUN ("setq", Fsetq, Ssetq, 0, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
429 430 431 432 433 434 435
       doc: /* Set each SYM to the value of its VAL.
The symbols SYM are variables; they are literal (not evaluated).
The values VAL are expressions; they are evaluated.
Thus, (setq x (1+ y)) sets `x' to the value of `(1+ y)'.
The second VAL is not computed until after the first SYM is set, and so on;
each VAL can use the new value of variables set earlier in the `setq'.
The return value of the `setq' form is the value of the last VAL.
Juanma Barranquero's avatar
Juanma Barranquero committed
436
usage: (setq [SYM VAL]...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
437
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
438 439
{
  register Lisp_Object args_left;
440
  register Lisp_Object val, sym, lex_binding;
Jim Blandy's avatar
Jim Blandy committed
441 442
  struct gcpro gcpro1;

443
  if (NILP (args))
Jim Blandy's avatar
Jim Blandy committed
444 445 446 447 448 449 450
    return Qnil;

  args_left = args;
  GCPRO1 (args);

  do
    {
451
      val = eval_sub (Fcar (Fcdr (args_left)));
Jim Blandy's avatar
Jim Blandy committed
452
      sym = Fcar (args_left);
453

454
      /* Like for eval_sub, we do not check declared_special here since
455 456
	 it's been done when let-binding.  */
      if (!NILP (Vinternal_interpreter_environment) /* Mere optimization!  */
457
	  && SYMBOLP (sym)
458 459
	  && !NILP (lex_binding
		    = Fassq (sym, Vinternal_interpreter_environment)))
460 461 462 463
	XSETCDR (lex_binding, val); /* SYM is lexically bound.  */
      else
	Fset (sym, val);	/* SYM is dynamically bound.  */

Jim Blandy's avatar
Jim Blandy committed
464 465
      args_left = Fcdr (Fcdr (args_left));
    }
Jim Blandy's avatar
Jim Blandy committed
466
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
467 468 469 470

  UNGCPRO;
  return val;
}
471

Jim Blandy's avatar
Jim Blandy committed
472
DEFUN ("quote", Fquote, Squote, 1, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
473 474
       doc: /* Return the argument, without evaluating it.  `(quote x)' yields `x'.
usage: (quote ARG)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
475
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
476
{
477 478
  if (!NILP (Fcdr (args)))
    xsignal2 (Qwrong_number_of_arguments, Qquote, Flength (args));
Jim Blandy's avatar
Jim Blandy committed
479 480
  return Fcar (args);
}
481

Jim Blandy's avatar
Jim Blandy committed
482
DEFUN ("function", Ffunction, Sfunction, 1, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
483 484 485 486
       doc: /* Like `quote', but preferred for objects which are functions.
In byte compilation, `function' causes its argument to be compiled.
`quote' cannot do that.
usage: (function ARG)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
487
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
488
{
489 490
  Lisp_Object quoted = XCAR (args);

491 492
  if (!NILP (Fcdr (args)))
    xsignal2 (Qwrong_number_of_arguments, Qfunction, Flength (args));
493 494 495 496 497 498

  if (!NILP (Vinternal_interpreter_environment)
      && CONSP (quoted)
      && EQ (XCAR (quoted), Qlambda))
    /* This is a lambda expression within a lexical environment;
       return an interpreted closure instead of a simple lambda.  */
499 500
    return Fcons (Qclosure, Fcons (Vinternal_interpreter_environment,
				   XCDR (quoted)));
501 502 503
  else
    /* Simply quote the argument.  */
    return quoted;
Jim Blandy's avatar
Jim Blandy committed
504 505
}

506

Jim Blandy's avatar
Jim Blandy committed
507
DEFUN ("interactive-p", Finteractive_p, Sinteractive_p, 0, 0, 0,
508
       doc: /* Return t if the containing function was run directly by user input.
509 510
This means that the function was called with `call-interactively'
\(which includes being called as the binding of a key)
511
and input is currently coming from the keyboard (not a keyboard macro),
512 513 514 515 516 517 518 519
and Emacs is not running in batch mode (`noninteractive' is nil).

The only known proper use of `interactive-p' is in deciding whether to
display a helpful message, or how to display it.  If you're thinking
of using it for any other purpose, it is quite likely that you're
making a mistake.  Think: what do you want to do when the command is
called from a keyboard macro?

520 521 522 523
To test whether your function was called with `call-interactively',
either (i) add an extra optional argument and give it an `interactive'
spec that specifies non-nil unconditionally (such as \"p\"); or (ii)
use `called-interactively-p'.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
524
  (void)
Jim Blandy's avatar
Jim Blandy committed
525
{
526
  return interactive_p (1) ? Qt : Qnil;
527 528 529
}


530
DEFUN ("called-interactively-p", Fcalled_interactively_p, Scalled_interactively_p, 0, 1, 0,
531
       doc: /* Return t if the containing function was called by `call-interactively'.
532 533 534 535 536 537 538 539 540 541 542 543
If KIND is `interactive', then only return t if the call was made
interactively by the user, i.e. not in `noninteractive' mode nor
when `executing-kbd-macro'.
If KIND is `any', on the other hand, it will return t for any kind of
interactive call, including being called as the binding of a key, or
from a keyboard macro, or in `noninteractive' mode.

The only known proper use of `interactive' for KIND is in deciding
whether to display a helpful message, or how to display it.  If you're
thinking of using it for any other purpose, it is quite likely that
you're making a mistake.  Think: what do you want to do when the
command is called from a keyboard macro?
544 545 546 547 548

This function is meant for implementing advice and other
function-modifying features.  Instead of using this, it is sometimes
cleaner to give your function an extra optional argument whose
`interactive' spec specifies non-nil unconditionally (\"p\" is a good
549
way to do this), or via (not (or executing-kbd-macro noninteractive)).  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
550
  (Lisp_Object kind)
551
{
552 553
  return ((INTERACTIVE || !EQ (kind, intern ("interactive")))
	  && interactive_p (1)) ? Qt : Qnil;
554 555 556 557 558
}


/*  Return 1 if function in which this appears was called using
    call-interactively.
559 560 561 562

    EXCLUDE_SUBRS_P non-zero means always return 0 if the function
    called is a built-in.  */

Andreas Schwab's avatar
Andreas Schwab committed
563
static int
564
interactive_p (int exclude_subrs_p)
565 566 567
{
  struct backtrace *btp;
  Lisp_Object fun;
Jim Blandy's avatar
Jim Blandy committed
568 569

  btp = backtrace_list;
Jim Blandy's avatar
Jim Blandy committed
570 571

  /* If this isn't a byte-compiled function, there may be a frame at
572
     the top for Finteractive_p.  If so, skip it.  */
573
  fun = Findirect_function (*btp->function, Qnil);
574 575
  if (SUBRP (fun) && (XSUBR (fun) == &Sinteractive_p
		      || XSUBR (fun) == &Scalled_interactively_p))
Jim Blandy's avatar
Jim Blandy committed
576
    btp = btp->next;
Jim Blandy's avatar
Jim Blandy committed
577 578

  /* If we're running an Emacs 18-style byte-compiled function, there
579 580 581
     may be a frame for Fbytecode at the top level.  In any version of
     Emacs there can be Fbytecode frames for subexpressions evaluated
     inside catch and condition-case.  Skip past them.
Jim Blandy's avatar
Jim Blandy committed
582

583
     If this isn't a byte-compiled function, then we may now be
Jim Blandy's avatar
Jim Blandy committed
584
     looking at several frames for special forms.  Skip past them.  */
585 586
  while (btp
	 && (EQ (*btp->function, Qbytecode)
587
	     || btp->nargs == UNEVALLED))
Jim Blandy's avatar
Jim Blandy committed
588 589
    btp = btp->next;

590
  /* `btp' now points at the frame of the innermost function that isn't
Jim Blandy's avatar
Jim Blandy committed
591 592 593
     a special form, ignoring frames for Finteractive_p and/or
     Fbytecode at the top.  If this frame is for a built-in function
     (such as load or eval-region) return nil.  */
594
  fun = Findirect_function (*btp->function, Qnil);
595 596
  if (exclude_subrs_p && SUBRP (fun))
    return 0;
597

598
  /* `btp' points to the frame of a Lisp function that called interactive-p.
Jim Blandy's avatar
Jim Blandy committed
599 600
     Return t if that function was called interactively.  */
  if (btp && btp->next && EQ (*btp->next->function, Qcall_interactively))
601 602
    return 1;
  return 0;
Jim Blandy's avatar
Jim Blandy committed
603 604
}

605

Jim Blandy's avatar
Jim Blandy committed
606
DEFUN ("defun", Fdefun, Sdefun, 2, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
607 608 609
       doc: /* Define NAME as a function.
The definition is (lambda ARGLIST [DOCSTRING] BODY...).
See also the function `interactive'.
610
usage: (defun NAME ARGLIST [DOCSTRING] BODY...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
611
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
612 613 614 615 616
{
  register Lisp_Object fn_name;
  register Lisp_Object defn;

  fn_name = Fcar (args);
617
  CHECK_SYMBOL (fn_name);
Jim Blandy's avatar
Jim Blandy committed
618
  defn = Fcons (Qlambda, Fcdr (args));
619 620
  if (!NILP (Vinternal_interpreter_environment)) /* Mere optimization!  */
    defn = Ffunction (Fcons (defn, Qnil));
Jim Blandy's avatar
Jim Blandy committed
621
  if (!NILP (Vpurify_flag))
Jim Blandy's avatar
Jim Blandy committed
622
    defn = Fpurecopy (defn);
623 624 625
  if (CONSP (XSYMBOL (fn_name)->function)
      && EQ (XCAR (XSYMBOL (fn_name)->function), Qautoload))
    LOADHIST_ATTACH (Fcons (Qt, fn_name));
Jim Blandy's avatar
Jim Blandy committed
626
  Ffset (fn_name, defn);
627
  LOADHIST_ATTACH (Fcons (Qdefun, fn_name));
Jim Blandy's avatar
Jim Blandy committed
628 629 630 631
  return fn_name;
}

DEFUN ("defmacro", Fdefmacro, Sdefmacro, 2, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
632
       doc: /* Define NAME as a macro.
Richard M. Stallman's avatar
Richard M. Stallman committed
633 634
The actual definition looks like
 (macro lambda ARGLIST [DOCSTRING] [DECL] BODY...).
Pavel Janík's avatar
Pavel Janík committed
635 636 637 638
When the macro is called, as in (NAME ARGS...),
the function (lambda ARGLIST BODY...) is applied to
the list ARGS... as it appears in the expression,
and the result should be a form to be evaluated instead of the original.
Richard M. Stallman's avatar
Richard M. Stallman committed
639 640

DECL is a declaration, optional, which can specify how to indent
John Paul Wallington's avatar
John Paul Wallington committed
641 642
calls to this macro, how Edebug should handle it, and which argument
should be treated as documentation.  It looks like this:
Richard M. Stallman's avatar
Richard M. Stallman committed
643 644 645 646 647
  (declare SPECS...)
The elements can look like this:
  (indent INDENT)
	Set NAME's `lisp-indent-function' property to INDENT.

648
  (debug DEBUG)
Richard M. Stallman's avatar
Richard M. Stallman committed
649
	Set NAME's `edebug-form-spec' property to DEBUG.  (This is
Juanma Barranquero's avatar
Juanma Barranquero committed
650
	equivalent to writing a `def-edebug-spec' for the macro.)
John Paul Wallington's avatar
John Paul Wallington committed
651 652 653 654

  (doc-string ELT)
	Set NAME's `doc-string-elt' property to ELT.

Richard M. Stallman's avatar
Richard M. Stallman committed
655
usage: (defmacro NAME ARGLIST [DOCSTRING] [DECL] BODY...)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
656
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
657 658 659
{
  register Lisp_Object fn_name;
  register Lisp_Object defn;
660
  Lisp_Object lambda_list, doc, tail;
Jim Blandy's avatar
Jim Blandy committed
661 662

  fn_name = Fcar (args);
663
  CHECK_SYMBOL (fn_name);
664 665 666 667 668 669
  lambda_list = Fcar (Fcdr (args));
  tail = Fcdr (Fcdr (args));

  doc = Qnil;
  if (STRINGP (Fcar (tail)))
    {
670 671
      doc = XCAR (tail);
      tail = XCDR (tail);
672 673
    }

674 675
  if (CONSP (Fcar (tail))
      && EQ (Fcar (Fcar (tail)), Qdeclare))
676 677 678 679 680 681 682 683
    {
      if (!NILP (Vmacro_declaration_function))
	{
	  struct gcpro gcpro1;
	  GCPRO1 (args);
	  call2 (Vmacro_declaration_function, fn_name, Fcar (tail));
	  UNGCPRO;
	}
684

685 686 687 688 689 690 691
      tail = Fcdr (tail);
    }

  if (NILP (doc))
    tail = Fcons (lambda_list, tail);
  else
    tail = Fcons (lambda_list, Fcons (doc, tail));
692

693
  defn = Fcons (Qlambda, tail);
694 695
  if (!NILP (Vinternal_interpreter_environment)) /* Mere optimization!  */
    defn = Ffunction (Fcons (defn, Qnil));
696
  defn = Fcons (Qmacro, defn);
697

Jim Blandy's avatar
Jim Blandy committed
698
  if (!NILP (Vpurify_flag))
Jim Blandy's avatar
Jim Blandy committed
699
    defn = Fpurecopy (defn);
700 701 702
  if (CONSP (XSYMBOL (fn_name)->function)
      && EQ (XCAR (XSYMBOL (fn_name)->function), Qautoload))
    LOADHIST_ATTACH (Fcons (Qt, fn_name));
Jim Blandy's avatar
Jim Blandy committed
703
  Ffset (fn_name, defn);
704
  LOADHIST_ATTACH (Fcons (Qdefun, fn_name));
Jim Blandy's avatar
Jim Blandy committed
705 706 707
  return fn_name;
}

Gerd Moellmann's avatar
Gerd Moellmann committed
708

709
DEFUN ("defvaralias", Fdefvaralias, Sdefvaralias, 2, 3, 0,
710
       doc: /* Make NEW-ALIAS a variable alias for symbol BASE-VARIABLE.
Richard M. Stallman's avatar
Richard M. Stallman committed
711
Aliased variables always have the same value; setting one sets the other.
712
Third arg DOCSTRING, if non-nil, is documentation for NEW-ALIAS.  If it is
713 714 715 716
omitted or nil, NEW-ALIAS gets the documentation string of BASE-VARIABLE,
or of the variable at the end of the chain of aliases, if BASE-VARIABLE is
itself an alias.  If NEW-ALIAS is bound, and BASE-VARIABLE is not,
then the value of BASE-VARIABLE is set to that of NEW-ALIAS.
717
The return value is BASE-VARIABLE.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
718
  (Lisp_Object new_alias, Lisp_Object base_variable, Lisp_Object docstring)
Gerd Moellmann's avatar
Gerd Moellmann committed
719 720
{
  struct Lisp_Symbol *sym;
721

722 723
  CHECK_SYMBOL (new_alias);
  CHECK_SYMBOL (base_variable);
Gerd Moellmann's avatar
Gerd Moellmann committed
724

725
  sym = XSYMBOL (new_alias);
726 727

  if (sym->constant)
Stefan Monnier's avatar
Stefan Monnier committed
728 729
    /* Not sure why, but why not?  */
    error ("Cannot make a constant an alias");
730 731 732 733 734 735 736 737 738

  switch (sym->redirect)
    {
    case SYMBOL_FORWARDED:
      error ("Cannot make an internal variable an alias");
    case SYMBOL_LOCALIZED:
      error ("Don't know how to make a localized variable an alias");
    }

739
  /* http://lists.gnu.org/archive/html/emacs-devel/2008-04/msg00834.html
740 741 742 743
     If n_a is bound, but b_v is not, set the value of b_v to n_a,
     so that old-code that affects n_a before the aliasing is setup
     still works.  */
  if (NILP (Fboundp (base_variable)))
744
    set_internal (base_variable, find_symbol_value (new_alias), Qnil, 1);
745 746 747 748 749 750 751 752 753 754 755

  {
    struct specbinding *p;

    for (p = specpdl_ptr - 1; p >= specpdl; p--)
      if (p->func == NULL
	  && (EQ (new_alias,
		  CONSP (p->symbol) ? XCAR (p->symbol) : p->symbol)))
	error ("Don't know how to make a let-bound variable an alias");
  }

756
  sym->declared_special = 1;
757 758
  sym->redirect = SYMBOL_VARALIAS;
  SET_SYMBOL_ALIAS (sym, XSYMBOL (base_variable));
759 760
  sym->constant = SYMBOL_CONSTANT_P (base_variable);
  LOADHIST_ATTACH (new_alias);
761 762
  /* Even if docstring is nil: remove old docstring.  */
  Fput (new_alias, Qvariable_documentation, docstring);
763

764
  return base_variable;
Gerd Moellmann's avatar
Gerd Moellmann committed
765 766 767
}


Jim Blandy's avatar
Jim Blandy committed
768
DEFUN ("defvar", Fdefvar, Sdefvar, 1, UNEVALLED, 0,
Juanma Barranquero's avatar
Juanma Barranquero committed
769
       doc: /* Define SYMBOL as a variable, and return SYMBOL.
Pavel Janík's avatar
Pavel Janík committed
770 771 772 773 774 775 776 777 778 779 780 781
You are not required to define a variable in order to use it,
but the definition can supply documentation and an initial value
in a way that tags can recognize.

INITVALUE is evaluated, and used to set SYMBOL, only if SYMBOL's value is void.
If SYMBOL is buffer-local, its default value is what is set;
 buffer-local values are not affected.
INITVALUE and DOCSTRING are optional.
If DOCSTRING starts with *, this variable is identified as a user option.
 This means that M-x set-variable recognizes it.
 See also `user-variable-p'.
If INITVALUE is missing, SYMBOL's value is not set.
782 783 784 785 786 787 788

If SYMBOL has a local binding, then this form affects the local
binding.  This is usually not what you want.  Thus, if you need to
load a file defining variables, with this form or with `defconst' or
`defcustom', you should always load that file _outside_ any bindings
for these variables.  \(`defconst' and `defcustom' behave similarly in
this respect.)
789
usage: (defvar SYMBOL &optional INITVALUE DOCSTRING)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
790
  (Lisp_Object args)
Jim Blandy's avatar
Jim Blandy committed
791
{
792
  register Lisp_Object sym, tem, tail;
Jim Blandy's avatar
Jim Blandy committed
793 794

  sym = Fcar (args);
795 796
  tail = Fcdr (args);
  if (!NILP (Fcdr (Fcdr (tail))))
797
    error ("Too many arguments");
798

799
  tem = Fdefault_boundp (sym);
800
  if (!NILP (tail))
Jim Blandy's avatar
Jim Blandy committed
801
    {
802 803
      /* Do it before evaluating the initial value, for self-references.  */
      XSYMBOL (sym)->declared_special = 1;
804

805 806 807
      if (SYMBOL_CONSTANT_P (sym))
	{
	  /* For upward compatibility, allow (defvar :foo (quote :foo)).  */
808 809 810 811 812
	  Lisp_Object tem1 = Fcar (tail);
	  if (! (CONSP (tem1)
		 && EQ (XCAR (tem1), Qquote)
		 && CONSP (XCDR (tem1))
		 && EQ (XCAR (XCDR (tem1)), sym)))
813 814 815 816
	    error ("Constant symbol `%s' specified in defvar",
		   SDATA (SYMBOL_NAME (sym)));
	}

Jim Blandy's avatar
Jim Blandy committed
817
      if (NILP (tem))
818
	Fset_default (sym, eval_sub (Fcar (tail)));
819 820 821
      else
	{ /* Check if there is really a global binding rather than just a let
	     binding that shadows the global unboundness of the var.  */
822
	  volatile struct specbinding *pdl = specpdl_ptr;
823 824 825 826 827 828 829 830 831 832 833
	  while (--pdl >= specpdl)
	    {
	      if (EQ (pdl->symbol, sym) && !pdl->func
		  && EQ (pdl->old_value, Qunbound))
		{
		  message_with_string ("Warning: defvar ignored because %s is let-bound",
				       SYMBOL_NAME (sym), 1);
		  break;
		}
	    }
	}
834
      tail = Fcdr (tail);
835 836
      tem = Fcar (tail);
      if (!NILP (tem))
837 838 839 840 841
	{
	  if (!NILP (Vpurify_flag))
	    tem = Fpurecopy (tem);
	  Fput (sym, Qvariable_documentation, tem);
	}
842
      LOADHIST_ATTACH (sym);
Jim Blandy's avatar
Jim Blandy committed
843
    }
844 845 846 847 848 849 850
  else if (!NILP (Vinternal_interpreter_environment)
	   && !XSYMBOL (sym)->declared_special)
    /* A simple (defvar foo) with lexical scoping does "nothing" except
       declare that var to be dynamically scoped *locally* (i.e. within
       the current file or let-block).  */
    Vinternal_interpreter_environment =
      Fcons (sym, Vinternal_interpreter_environment);
851
  else
852 853 854 855 856
    {
      /* Simple (defvar <var>) should not count as a definition at all.
	 It could get in the way of other definitions, and unloading this
	 package could try to make the variable unbound.  */
    }
Andreas Schwab's avatar
Andreas Schwab committed
857

Jim Blandy's avatar
Jim Blandy committed
858 859 860 861
  return sym;
}

DEFUN ("defconst", Fdefconst, Sdefconst, 2, UNEVALLED, 0,
Pavel Janík's avatar
Pavel Janík committed
862 863 864 865 866 867
       doc: /* Define SYMBOL as a constant variable.
The intent is that neither programs nor users should ever change this value.
Always sets the value of SYMBOL to the result of evalling INITVALUE.
If SYMBOL is buffer-local, its default value is what is set;
 buffer-local values are not affected.
DOCSTRING is optional.
Luc Teirlinck's avatar