eval.c 62.9 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* Evaluator for GNU Emacs Lisp interpreter.
Jim Blandy's avatar
Jim Blandy committed
2
   Copyright (C) 1985, 1986, 1987, 1992 Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.

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
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */


#include "config.h"
#include "lisp.h"
#ifdef HAVE_X_WINDOWS
#include "xterm.h"
#endif

#ifndef standalone
#include "commands.h"
Jim Blandy's avatar
Jim Blandy committed
29
#include "keyboard.h"
Jim Blandy's avatar
Jim Blandy committed
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
#else
#define INTERACTIVE 1
#endif

#include <setjmp.h>

/* This definition is duplicated in alloc.c and keyboard.c */
/* Putting it in lisp.h makes cc bomb out! */

struct backtrace
  {
    struct backtrace *next;
    Lisp_Object *function;
    Lisp_Object *args;	/* Points to vector of args. */
    int nargs;		/* length of vector */
	       /* if nargs is UNEVALLED, args points to slot holding list of unevalled args */
    char evalargs;
    /* Nonzero means call value of debugger when done with this operation. */
    char debug_on_exit;
  };

struct backtrace *backtrace_list;

struct catchtag
  {
    Lisp_Object tag;
    Lisp_Object val;
    struct catchtag *next;
    struct gcpro *gcpro;
    jmp_buf jmp;
    struct backtrace *backlist;
    struct handler *handlerlist;
    int lisp_eval_depth;
    int pdlcount;
    int poll_suppress_count;
  };

struct catchtag *catchlist;

Lisp_Object Qautoload, Qmacro, Qexit, Qinteractive, Qcommandp, Qdefun;
Jim Blandy's avatar
Jim Blandy committed
70
Lisp_Object Qinhibit_quit, Vinhibit_quit, Vquit_flag;
Jim Blandy's avatar
Jim Blandy committed
71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104
Lisp_Object Qmocklisp_arguments, Vmocklisp_arguments, Qmocklisp;
Lisp_Object Qand_rest, Qand_optional;
Lisp_Object Qdebug_on_error;

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:
   (FUN . ODEF) for a defun, (OFEATURES . nil) for a provide.  */

Lisp_Object Vautoload_queue;

/* Current number of specbindings allocated in specpdl.  */
int specpdl_size;

/* Pointer to beginning of specpdl.  */
struct specbinding *specpdl;

/* Pointer to first unused element in specpdl.  */
struct specbinding *specpdl_ptr;

/* Maximum size allowed for specpdl allocation */
int max_specpdl_size;

/* Depth in Lisp evaluations and function calls.  */
int lisp_eval_depth;

/* Maximum allowed depth in Lisp evaluations and function calls.  */
int max_lisp_eval_depth;

/* Nonzero means enter debugger before next function call */
int debug_on_next_call;

Roland McGrath's avatar
Roland McGrath committed
105 106 107
/* List of conditions (non-nil atom means all) which cause a backtrace
   if an error is handled by the command loop's error handler.
Lisp_Object Vstack_trace_on_error;
Jim Blandy's avatar
Jim Blandy committed
108

Roland McGrath's avatar
Roland McGrath committed
109 110 111
/* List of conditions (non-nil atom means all) which enter the debugger
   if an error is handled by the command loop's error handler.
Lisp_Object Vdebug_on_error;
Jim Blandy's avatar
Jim Blandy committed
112 113

/* Nonzero means enter debugger if a quit signal
Roland McGrath's avatar
Roland McGrath committed
114
   is handled by the command loop's error handler. */
Jim Blandy's avatar
Jim Blandy committed
115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183
int debug_on_quit;

/* Nonzero means we are trying to enter the debugger.
   This is to prevent recursive attempts.  */
int entering_debugger;

Lisp_Object Vdebugger;

void specbind (), record_unwind_protect ();

Lisp_Object funcall_lambda ();
extern Lisp_Object ml_apply (); /* Apply a mocklisp function to unevaluated argument list */

init_eval_once ()
{
  specpdl_size = 50;
  specpdl = (struct specbinding *) malloc (specpdl_size * sizeof (struct specbinding));
  max_specpdl_size = 600;
  max_lisp_eval_depth = 200;
}

init_eval ()
{
  specpdl_ptr = specpdl;
  catchlist = 0;
  handlerlist = 0;
  backtrace_list = 0;
  Vquit_flag = Qnil;
  debug_on_next_call = 0;
  lisp_eval_depth = 0;
  entering_debugger = 0;
}

Lisp_Object
call_debugger (arg)
     Lisp_Object arg;
{
  if (lisp_eval_depth + 20 > max_lisp_eval_depth)
    max_lisp_eval_depth = lisp_eval_depth + 20;
  if (specpdl_size + 40 > max_specpdl_size)
    max_specpdl_size = specpdl_size + 40;
  debug_on_next_call = 0;
  entering_debugger = 1;
  return apply1 (Vdebugger, arg);
}

do_debug_on_call (code)
     Lisp_Object code;
{
  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,
  "Eval args until one of them yields non-nil, then return that value.\n\
The remaining args are not evalled at all.\n\
If all args return nil, return nil.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object val;
  Lisp_Object args_left;
  struct gcpro gcpro1;

Jim Blandy's avatar
Jim Blandy committed
184
  if (NILP(args))
Jim Blandy's avatar
Jim Blandy committed
185 186 187 188 189 190 191 192
    return Qnil;

  args_left = args;
  GCPRO1 (args_left);

  do
    {
      val = Feval (Fcar (args_left));
Jim Blandy's avatar
Jim Blandy committed
193
      if (!NILP (val))
Jim Blandy's avatar
Jim Blandy committed
194 195 196
	break;
      args_left = Fcdr (args_left);
    }
Jim Blandy's avatar
Jim Blandy committed
197
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213

  UNGCPRO;
  return val;
}

DEFUN ("and", Fand, Sand, 0, UNEVALLED, 0,
  "Eval args until one of them yields nil, then return nil.\n\
The remaining args are not evalled at all.\n\
If no arg yields nil, return the last arg's value.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object val;
  Lisp_Object args_left;
  struct gcpro gcpro1;

Jim Blandy's avatar
Jim Blandy committed
214
  if (NILP(args))
Jim Blandy's avatar
Jim Blandy committed
215 216 217 218 219 220 221 222
    return Qt;

  args_left = args;
  GCPRO1 (args_left);

  do
    {
      val = Feval (Fcar (args_left));
Jim Blandy's avatar
Jim Blandy committed
223
      if (NILP (val))
Jim Blandy's avatar
Jim Blandy committed
224 225 226
	break;
      args_left = Fcdr (args_left);
    }
Jim Blandy's avatar
Jim Blandy committed
227
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247

  UNGCPRO;
  return val;
}

DEFUN ("if", Fif, Sif, 2, UNEVALLED, 0,
  "(if COND THEN ELSE...): if COND yields non-nil, do THEN, else do ELSE...\n\
Returns the value of THEN or the value of the last of the ELSE's.\n\
THEN must be one expression, but ELSE... can be zero or more expressions.\n\
If COND yields nil, and there are no ELSE's, the value is nil.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object cond;
  struct gcpro gcpro1;

  GCPRO1 (args);
  cond = Feval (Fcar (args));
  UNGCPRO;

Jim Blandy's avatar
Jim Blandy committed
248
  if (!NILP (cond))
Jim Blandy's avatar
Jim Blandy committed
249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269
    return Feval (Fcar (Fcdr (args)));
  return Fprogn (Fcdr (Fcdr (args)));
}

DEFUN ("cond", Fcond, Scond, 0, UNEVALLED, 0,
  "(cond CLAUSES...): try each clause until one succeeds.\n\
Each clause looks like (CONDITION BODY...).  CONDITION is evaluated\n\
and, if the value is non-nil, this clause succeeds:\n\
then the expressions in BODY are evaluated and the last one's\n\
value is the value of the cond-form.\n\
If no clause succeeds, cond returns nil.\n\
If a clause has one element, as in (CONDITION),\n\
CONDITION's value if non-nil is returned from the cond-form.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object clause, val;
  struct gcpro gcpro1;

  val = Qnil;
  GCPRO1 (args);
Jim Blandy's avatar
Jim Blandy committed
270
  while (!NILP (args))
Jim Blandy's avatar
Jim Blandy committed
271 272 273
    {
      clause = Fcar (args);
      val = Feval (Fcar (clause));
Jim Blandy's avatar
Jim Blandy committed
274
      if (!NILP (val))
Jim Blandy's avatar
Jim Blandy committed
275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
	{
	  if (!EQ (XCONS (clause)->cdr, Qnil))
	    val = Fprogn (XCONS (clause)->cdr);
	  break;
	}
      args = XCONS (args)->cdr;
    }
  UNGCPRO;

  return val;
}

DEFUN ("progn", Fprogn, Sprogn, 0, UNEVALLED, 0,
  "(progn BODY...): eval BODY forms sequentially and return value of last one.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object val, tem;
  Lisp_Object args_left;
  struct gcpro gcpro1;

  /* In Mocklisp code, symbols at the front of the progn arglist
   are to be bound to zero. */
  if (!EQ (Vmocklisp_arguments, Qt))
    {
      val = make_number (0);
Jim Blandy's avatar
Jim Blandy committed
301
      while (!NILP (args) && (tem = Fcar (args), XTYPE (tem) == Lisp_Symbol))
Jim Blandy's avatar
Jim Blandy committed
302 303 304 305 306 307
	{
	  QUIT;
	  specbind (tem, val), args = Fcdr (args);
	}
    }

Jim Blandy's avatar
Jim Blandy committed
308
  if (NILP(args))
Jim Blandy's avatar
Jim Blandy committed
309 310 311 312 313 314 315 316 317 318
    return Qnil;

  args_left = args;
  GCPRO1 (args_left);

  do
    {
      val = Feval (Fcar (args_left));
      args_left = Fcdr (args_left);
    }
Jim Blandy's avatar
Jim Blandy committed
319
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336

  UNGCPRO;
  return val;
}

DEFUN ("prog1", Fprog1, Sprog1, 1, UNEVALLED, 0,
  "(prog1 FIRST BODY...): eval FIRST and BODY sequentially; value from FIRST.\n\
The value of FIRST is saved during the evaluation of the remaining args,\n\
whose values are discarded.")
  (args)
     Lisp_Object args;
{
  Lisp_Object val;
  register Lisp_Object args_left;
  struct gcpro gcpro1, gcpro2;
  register int argnum = 0;

Jim Blandy's avatar
Jim Blandy committed
337
  if (NILP(args))
Jim Blandy's avatar
Jim Blandy committed
338 339 340 341 342 343 344 345 346 347 348 349 350 351
    return Qnil;

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

  do
    {
      if (!(argnum++))
        val = Feval (Fcar (args_left));
      else
	Feval (Fcar (args_left));
      args_left = Fcdr (args_left);
    }
Jim Blandy's avatar
Jim Blandy committed
352
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371

  UNGCPRO;
  return val;
}

DEFUN ("prog2", Fprog2, Sprog2, 2, UNEVALLED, 0,
  "(prog1 X Y BODY...): eval X, Y and BODY sequentially; value from Y.\n\
The value of Y is saved during the evaluation of the remaining args,\n\
whose values are discarded.")
  (args)
     Lisp_Object args;
{
  Lisp_Object val;
  register Lisp_Object args_left;
  struct gcpro gcpro1, gcpro2;
  register int argnum = -1;

  val = Qnil;

Jim Blandy's avatar
Jim Blandy committed
372
  if (NILP(args))
Jim Blandy's avatar
Jim Blandy committed
373 374 375 376 377 378 379 380 381 382 383 384 385 386
    return Qnil;

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

  do
    {
      if (!(argnum++))
        val = Feval (Fcar (args_left));
      else
	Feval (Fcar (args_left));
      args_left = Fcdr (args_left);
    }
Jim Blandy's avatar
Jim Blandy committed
387
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403

  UNGCPRO;
  return val;
}

DEFUN ("setq", Fsetq, Ssetq, 0, UNEVALLED, 0,
  "(setq SYM VAL SYM VAL ...): set each SYM to the value of its VAL.\n\
The SYMs are not evaluated.  Thus (setq x y) sets x to the value of y.\n\
Each SYM is set before the next VAL is computed.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object args_left;
  register Lisp_Object val, sym;
  struct gcpro gcpro1;

Jim Blandy's avatar
Jim Blandy committed
404
  if (NILP(args))
Jim Blandy's avatar
Jim Blandy committed
405 406 407 408 409 410 411 412 413 414 415 416
    return Qnil;

  args_left = args;
  GCPRO1 (args);

  do
    {
      val = Feval (Fcar (Fcdr (args_left)));
      sym = Fcar (args_left);
      Fset (sym, val);
      args_left = Fcdr (Fcdr (args_left));
    }
Jim Blandy's avatar
Jim Blandy committed
417
  while (!NILP(args_left));
Jim Blandy's avatar
Jim Blandy committed
418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457

  UNGCPRO;
  return val;
}
     
DEFUN ("quote", Fquote, Squote, 1, UNEVALLED, 0,
  "Return the argument, without evaluating it.  `(quote x)' yields `x'.")
  (args)
     Lisp_Object args;
{
  return Fcar (args);
}
     
DEFUN ("function", Ffunction, Sfunction, 1, UNEVALLED, 0,
  "Like `quote', but preferred for objects which are functions.\n\
In byte compilation, `function' causes its argument to be compiled.\n\
`quote' cannot do that.")
  (args)
     Lisp_Object args;
{
  return Fcar (args);
}

DEFUN ("interactive-p", Finteractive_p, Sinteractive_p, 0, 0, 0,
  "Return t if function in which this appears was called interactively.\n\
This means that the function was called with call-interactively (which\n\
includes being called as the binding of a key)\n\
and input is currently coming from the keyboard (not in keyboard macro).")
  ()
{
  register struct backtrace *btp;
  register Lisp_Object fun;

  if (!INTERACTIVE)
    return Qnil;

  /*  Unless the object was compiled, skip the frame of interactive-p itself
      (if interpreted) or the frame of byte-code (if called from
      compiled function).  */
  btp = backtrace_list;
Jim Blandy's avatar
Jim Blandy committed
458
  if (XTYPE (*btp->function) != Lisp_Compiled)
Jim Blandy's avatar
Jim Blandy committed
459
    btp = btp->next;
Jim Blandy's avatar
Jim Blandy committed
460 461 462 463
  while (btp
	 && (btp->nargs == UNEVALLED || EQ (*btp->function, Qbytecode)))
    btp = btp->next;

Jim Blandy's avatar
Jim Blandy committed
464 465 466 467
  /* btp now points at the frame of the innermost function
     that DOES eval its args.
     If it is a built-in function (such as load or eval-region)
     return nil.  */
Jim Blandy's avatar
Jim Blandy committed
468
  fun = Findirect_function (*btp->function);
Jim Blandy's avatar
Jim Blandy committed
469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489
  if (XTYPE (fun) == Lisp_Subr)
    return Qnil;
  /* btp points to the frame of a Lisp function that called interactive-p.
     Return t if that function was called interactively.  */
  if (btp && btp->next && EQ (*btp->next->function, Qcall_interactively))
    return Qt;
  return Qnil;
}

DEFUN ("defun", Fdefun, Sdefun, 2, UNEVALLED, 0,
  "(defun NAME ARGLIST [DOCSTRING] BODY...): define NAME as a function.\n\
The definition is (lambda ARGLIST [DOCSTRING] BODY...).\n\
See also the function `interactive'.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object fn_name;
  register Lisp_Object defn;

  fn_name = Fcar (args);
  defn = Fcons (Qlambda, Fcdr (args));
Jim Blandy's avatar
Jim Blandy committed
490
  if (!NILP (Vpurify_flag))
Jim Blandy's avatar
Jim Blandy committed
491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510
    defn = Fpurecopy (defn);
  Ffset (fn_name, defn);
  return fn_name;
}

DEFUN ("defmacro", Fdefmacro, Sdefmacro, 2, UNEVALLED, 0,
  "(defmacro NAME ARGLIST [DOCSTRING] BODY...): define NAME as a macro.\n\
The definition is (macro lambda ARGLIST [DOCSTRING] BODY...).\n\
When the macro is called, as in (NAME ARGS...),\n\
the function (lambda ARGLIST BODY...) is applied to\n\
the list ARGS... as it appears in the expression,\n\
and the result should be a form to be evaluated instead of the original.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object fn_name;
  register Lisp_Object defn;

  fn_name = Fcar (args);
  defn = Fcons (Qmacro, Fcons (Qlambda, Fcdr (args)));
Jim Blandy's avatar
Jim Blandy committed
511
  if (!NILP (Vpurify_flag))
Jim Blandy's avatar
Jim Blandy committed
512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534
    defn = Fpurecopy (defn);
  Ffset (fn_name, defn);
  return fn_name;
}

DEFUN ("defvar", Fdefvar, Sdefvar, 1, UNEVALLED, 0,
  "(defvar SYMBOL INITVALUE DOCSTRING): define SYMBOL as a variable.\n\
You are not required to define a variable in order to use it,\n\
but the definition can supply documentation and an initial value\n\
in a way that tags can recognize.\n\n\
INITVALUE is evaluated, and used to set SYMBOL, only if SYMBOL's value is void.\n\
If SYMBOL is buffer-local, its default value is initialized in this way.\n\
INITVALUE and DOCSTRING are optional.\n\
If DOCSTRING starts with *, this variable is identified as a user option.\n\
 This means that M-x set-variable and M-x edit-options recognize it.\n\
If INITVALUE is missing, SYMBOL's value is not set.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object sym, tem;

  sym = Fcar (args);
  tem = Fcdr (args);
Jim Blandy's avatar
Jim Blandy committed
535
  if (!NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
536 537
    {
      tem = Fdefault_boundp (sym);
Jim Blandy's avatar
Jim Blandy committed
538
      if (NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
539 540 541
	Fset_default (sym, Feval (Fcar (Fcdr (args))));
    }
  tem = Fcar (Fcdr (Fcdr (args)));
Jim Blandy's avatar
Jim Blandy committed
542
  if (!NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
543
    {
Jim Blandy's avatar
Jim Blandy committed
544
      if (!NILP (Vpurify_flag))
Jim Blandy's avatar
Jim Blandy committed
545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571
	tem = Fpurecopy (tem);
      Fput (sym, Qvariable_documentation, tem);
    }
  return sym;
}

DEFUN ("defconst", Fdefconst, Sdefconst, 2, UNEVALLED, 0,
  "(defconst SYMBOL INITVALUE DOCSTRING): define SYMBOL as a constant variable.\n\
The intent is that programs do not change this value, but users may.\n\
Always sets the value of SYMBOL to the result of evalling INITVALUE.\n\
If SYMBOL is buffer-local, its default value is initialized in this way.\n\
DOCSTRING is optional.\n\
If DOCSTRING starts with *, this variable is identified as a user option.\n\
 This means that M-x set-variable and M-x edit-options recognize it.\n\n\
Note: do not use `defconst' for user options in libraries that are not\n\
normally loaded, since it is useful for users to be able to specify\n\
their own values for such variables before loading the library.\n\
Since `defconst' unconditionally assigns the variable,\n\
it would override the user's choice.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object sym, tem;

  sym = Fcar (args);
  Fset_default (sym, Feval (Fcar (Fcdr (args))));
  tem = Fcar (Fcdr (Fcdr (args)));
Jim Blandy's avatar
Jim Blandy committed
572
  if (!NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
573
    {
Jim Blandy's avatar
Jim Blandy committed
574
      if (!NILP (Vpurify_flag))
Jim Blandy's avatar
Jim Blandy committed
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615
	tem = Fpurecopy (tem);
      Fput (sym, Qvariable_documentation, tem);
    }
  return sym;
}

DEFUN ("user-variable-p", Fuser_variable_p, Suser_variable_p, 1, 1, 0,
  "Returns t if VARIABLE is intended to be set and modified by users.\n\
\(The alternative is a variable used internally in a Lisp program.)\n\
Determined by whether the first character of the documentation\n\
for the variable is \"*\"")
  (variable)
     Lisp_Object variable;
{
  Lisp_Object documentation;
  
  documentation = Fget (variable, Qvariable_documentation);
  if (XTYPE (documentation) == Lisp_Int && XINT (documentation) < 0)
    return Qt;
  if ((XTYPE (documentation) == Lisp_String) &&
      ((unsigned char) XSTRING (documentation)->data[0] == '*'))
    return Qt;
  return Qnil;
}  

DEFUN ("let*", FletX, SletX, 1, UNEVALLED, 0,
  "(let* VARLIST BODY...): bind variables according to VARLIST then eval BODY.\n\
The value of the last form in BODY is returned.\n\
Each element of VARLIST is a symbol (which is bound to nil)\n\
or a list (SYMBOL VALUEFORM) (which binds SYMBOL to the value of VALUEFORM).\n\
Each VALUEFORM can refer to the symbols already bound by this VARLIST.")
  (args)
     Lisp_Object args;
{
  Lisp_Object varlist, val, elt;
  int count = specpdl_ptr - specpdl;
  struct gcpro gcpro1, gcpro2, gcpro3;

  GCPRO3 (args, elt, varlist);

  varlist = Fcar (args);
Jim Blandy's avatar
Jim Blandy committed
616
  while (!NILP (varlist))
Jim Blandy's avatar
Jim Blandy committed
617 618 619 620 621
    {
      QUIT;
      elt = Fcar (varlist);
      if (XTYPE (elt) == Lisp_Symbol)
	specbind (elt, Qnil);
Jim Blandy's avatar
Jim Blandy committed
622 623 624 625
      else if (! NILP (Fcdr (Fcdr (elt))))
	Fsignal (Qerror,
		 Fcons (build_string ("`let' bindings can have only one value-form"),
			elt));
Jim Blandy's avatar
Jim Blandy committed
626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663
      else
	{
	  val = Feval (Fcar (Fcdr (elt)));
	  specbind (Fcar (elt), val);
	}
      varlist = Fcdr (varlist);
    }
  UNGCPRO;
  val = Fprogn (Fcdr (args));
  return unbind_to (count, val);
}

DEFUN ("let", Flet, Slet, 1, UNEVALLED, 0,
  "(let VARLIST BODY...): bind variables according to VARLIST then eval BODY.\n\
The value of the last form in BODY is returned.\n\
Each element of VARLIST is a symbol (which is bound to nil)\n\
or a list (SYMBOL VALUEFORM) (which binds SYMBOL to the value of VALUEFORM).\n\
All the VALUEFORMs are evalled before any symbols are bound.")
  (args)
     Lisp_Object args;
{
  Lisp_Object *temps, tem;
  register Lisp_Object elt, varlist;
  int count = specpdl_ptr - specpdl;
  register int argnum;
  struct gcpro gcpro1, gcpro2;

  varlist = Fcar (args);

  /* Make space to hold the values to give the bound variables */
  elt = Flength (varlist);
  temps = (Lisp_Object *) alloca (XFASTINT (elt) * sizeof (Lisp_Object));

  /* Compute the values and store them in `temps' */

  GCPRO2 (args, *temps);
  gcpro2.nvars = 0;

Jim Blandy's avatar
Jim Blandy committed
664
  for (argnum = 0; !NILP (varlist); varlist = Fcdr (varlist))
Jim Blandy's avatar
Jim Blandy committed
665 666 667 668 669
    {
      QUIT;
      elt = Fcar (varlist);
      if (XTYPE (elt) == Lisp_Symbol)
	temps [argnum++] = Qnil;
Jim Blandy's avatar
Jim Blandy committed
670 671 672 673
      else if (! NILP (Fcdr (Fcdr (elt))))
	Fsignal (Qerror,
		 Fcons (build_string ("`let' bindings can have only one value-form"),
			elt));
Jim Blandy's avatar
Jim Blandy committed
674 675 676 677 678 679 680
      else
	temps [argnum++] = Feval (Fcar (Fcdr (elt)));
      gcpro2.nvars = argnum;
    }
  UNGCPRO;

  varlist = Fcar (args);
Jim Blandy's avatar
Jim Blandy committed
681
  for (argnum = 0; !NILP (varlist); varlist = Fcdr (varlist))
Jim Blandy's avatar
Jim Blandy committed
682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708
    {
      elt = Fcar (varlist);
      tem = temps[argnum++];
      if (XTYPE (elt) == Lisp_Symbol)
	specbind (elt, tem);
      else
	specbind (Fcar (elt), tem);
    }

  elt = Fprogn (Fcdr (args));
  return unbind_to (count, elt);
}

DEFUN ("while", Fwhile, Swhile, 1, UNEVALLED, 0,
  "(while TEST BODY...): if TEST yields non-nil, eval BODY... and repeat.\n\
The order of execution is thus TEST, BODY, TEST, BODY and so on\n\
until TEST returns nil.")
  (args)
     Lisp_Object args;
{
  Lisp_Object test, body, tem;
  struct gcpro gcpro1, gcpro2;

  GCPRO2 (test, body);

  test = Fcar (args);
  body = Fcdr (args);
Jim Blandy's avatar
Jim Blandy committed
709
  while (tem = Feval (test), !NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753
    {
      QUIT;
      Fprogn (body);
    }

  UNGCPRO;
  return Qnil;
}

DEFUN ("macroexpand", Fmacroexpand, Smacroexpand, 1, 2, 0,
  "Return result of expanding macros at top level of FORM.\n\
If FORM is not a macro call, it is returned unchanged.\n\
Otherwise, the macro is expanded and the expansion is considered\n\
in place of FORM.  When a non-macro-call results, it is returned.\n\n\
The second optional arg ENVIRONMENT species an environment of macro\n\
definitions to shadow the loaded ones for use in file byte-compilation.")
  (form, env)
     register Lisp_Object form;
     Lisp_Object env;
{
  register Lisp_Object expander, sym, def, tem;

  while (1)
    {
      /* Come back here each time we expand a macro call,
	 in case it expands into another macro call.  */
      if (XTYPE (form) != Lisp_Cons)
	break;
      sym = XCONS (form)->car;
      /* Detect  ((macro lambda ...) ...)  */
      if (XTYPE (sym) == Lisp_Cons
	  && EQ (XCONS (sym)->car, Qmacro))
	{
	  expander = XCONS (sym)->cdr;
	  goto explicit;
	}
      if (XTYPE (sym) != Lisp_Symbol)
	break;
      /* Trace symbols aliases to other symbols
	 until we get a symbol that is not an alias.  */
      while (1)
	{
	  QUIT;
	  tem = Fassq (sym, env);
Jim Blandy's avatar
Jim Blandy committed
754
	  if (NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
	    {
	      def = XSYMBOL (sym)->function;
	      if (XTYPE (def) == Lisp_Symbol && !EQ (def, Qunbound))
		sym = def;
	      else
		break;
	    }
	  else
	    {
#if 0  /* This is turned off because it caused an element (foo . bar)
	  to have the effect of defining foo as an alias for the macro bar.
	  That is inconsistent; bar should be a function to expand foo.  */
	      if (XTYPE (tem) == Lisp_Cons
		  && XTYPE (XCONS (tem)->cdr) == Lisp_Symbol)
		sym = XCONS (tem)->cdr;
	      else
#endif
		break;
	    }
	}
      /* Right now TEM is the result from SYM in ENV,
	 and if TEM is nil then DEF is SYM's function definition.  */
Jim Blandy's avatar
Jim Blandy committed
777
      if (NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
778 779 780 781 782 783 784 785 786 787 788
	{
	  /* SYM is not mentioned in ENV.
	     Look at its function definition.  */
	  if (EQ (def, Qunbound)
	      || XTYPE (def) != Lisp_Cons)
	    /* Not defined or definition not suitable */
	    break;
	  if (EQ (XCONS (def)->car, Qautoload))
	    {
	      /* Autoloading function: will it be a macro when loaded?  */
	      tem = Fcar (Fnthcdr (make_number (4), def));
Jim Blandy's avatar
Jim Blandy committed
789
	      if (NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
790 791 792 793 794 795 796 797 798 799 800 801
		break;
	      /* Yes, load it and try again.  */
	      do_autoload (def, sym);
	      continue;
	    }
	  else if (!EQ (XCONS (def)->car, Qmacro))
	    break;
	  else expander = XCONS (def)->cdr;
	}
      else
	{
	  expander = XCONS (tem)->cdr;
Jim Blandy's avatar
Jim Blandy committed
802
	  if (NILP (expander))
Jim Blandy's avatar
Jim Blandy committed
803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903
	    break;
	}
    explicit:
      form = apply1 (expander, XCONS (form)->cdr);
    }
  return form;
}

DEFUN ("catch", Fcatch, Scatch, 1, UNEVALLED, 0,
  "(catch TAG BODY...): eval BODY allowing nonlocal exits using `throw'.\n\
TAG is evalled to get the tag to use.  Then the BODY is executed.\n\
Within BODY, (throw TAG) with same tag exits BODY and exits this `catch'.\n\
If no throw happens, `catch' returns the value of the last BODY form.\n\
If a throw happens, it specifies the value to return from `catch'.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object tag;
  struct gcpro gcpro1;

  GCPRO1 (args);
  tag = Feval (Fcar (args));
  UNGCPRO;
  return internal_catch (tag, Fprogn, Fcdr (args));
}

/* Set up a catch, then call C function FUNC on argument ARG.
   FUNC should return a Lisp_Object.
   This is how catches are done from within C code. */

Lisp_Object
internal_catch (tag, func, arg)
     Lisp_Object tag;
     Lisp_Object (*func) ();
     Lisp_Object arg;
{
  /* This structure is made part of the chain `catchlist'.  */
  struct catchtag c;

  /* Fill in the components of c, and put it on the list.  */
  c.next = catchlist;
  c.tag = tag;
  c.val = Qnil;
  c.backlist = backtrace_list;
  c.handlerlist = handlerlist;
  c.lisp_eval_depth = lisp_eval_depth;
  c.pdlcount = specpdl_ptr - specpdl;
  c.poll_suppress_count = poll_suppress_count;
  c.gcpro = gcprolist;
  catchlist = &c;

  /* Call FUNC.  */
  if (! _setjmp (c.jmp))
    c.val = (*func) (arg);

  /* Throw works by a longjmp that comes right here.  */
  catchlist = c.next;
  return c.val;
}

/* Discard from the catchlist all catch tags back through CATCH.
   Before each catch is discarded, unbind all special bindings
   made within that catch.  Also, when discarding a catch that
   corresponds to a condition handler, discard that handler.

   At the end, restore some static info saved in CATCH.

   This is used for correct unwinding in Fthrow and Fsignal,
   before doing the longjmp that actually destroys the stack frames
   in which these handlers and catches reside.  */

static void
unbind_catch (catch)
     struct catchtag *catch;
{
  register int last_time;

  do
    {
      last_time = catchlist == catch;
      unbind_to (catchlist->pdlcount, Qnil);
      handlerlist = catchlist->handlerlist;
      catchlist = catchlist->next;
    }
  while (! last_time);

  gcprolist = catch->gcpro;
  backtrace_list = catch->backlist;
  lisp_eval_depth = catch->lisp_eval_depth;
}

DEFUN ("throw", Fthrow, Sthrow, 2, 2, 0,
  "(throw TAG VALUE): throw to the catch for TAG and return VALUE from it.\n\
Both TAG and VALUE are evalled.")
  (tag, val)
     register Lisp_Object tag, val;
{
  register struct catchtag *c;

  while (1)
    {
Jim Blandy's avatar
Jim Blandy committed
904
      if (!NILP (tag))
Jim Blandy's avatar
Jim Blandy committed
905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986
	for (c = catchlist; c; c = c->next)
	  {
	    if (EQ (c->tag, tag))
	      {
		/* Restore the polling-suppression count.  */
		if (c->poll_suppress_count > poll_suppress_count)
		  abort ();
		while (c->poll_suppress_count < poll_suppress_count)
		  start_polling ();
		c->val = val;
		unbind_catch (c);
		_longjmp (c->jmp, 1);
	      }
	  }
      tag = Fsignal (Qno_catch, Fcons (tag, Fcons (val, Qnil)));
    }
}


DEFUN ("unwind-protect", Funwind_protect, Sunwind_protect, 1, UNEVALLED, 0,
  "Do BODYFORM, protecting with UNWINDFORMS.\n\
Usage looks like (unwind-protect BODYFORM UNWINDFORMS...).\n\
If BODYFORM completes normally, its value is returned\n\
after executing the UNWINDFORMS.\n\
If BODYFORM exits nonlocally, the UNWINDFORMS are executed anyway.")
  (args)
     Lisp_Object args;
{
  Lisp_Object val;
  int count = specpdl_ptr - specpdl;

  record_unwind_protect (0, Fcdr (args));
  val = Feval (Fcar (args));
  return unbind_to (count, val);  
}

/* Chain of condition handlers currently in effect.
   The elements of this chain are contained in the stack frames
   of Fcondition_case and internal_condition_case.
   When an error is signaled (by calling Fsignal, below),
   this chain is searched for an element that applies.  */

struct handler *handlerlist;

DEFUN ("condition-case", Fcondition_case, Scondition_case, 2, UNEVALLED, 0,
  "Regain control when an error is signaled.\n\
Usage looks like (condition-case VAR BODYFORM HANDLERS...).\n\
executes BODYFORM and returns its value if no error happens.\n\
Each element of HANDLERS looks like (CONDITION-NAME BODY...)\n\
where the BODY is made of Lisp expressions.\n\n\
A handler is applicable to an error\n\
if CONDITION-NAME is one of the error's condition names.\n\
If an error happens, the first applicable handler is run.\n\
\n\
When a handler handles an error,\n\
control returns to the condition-case and the handler BODY... is executed\n\
with VAR bound to (SIGNALED-CONDITIONS . SIGNAL-DATA).\n\
VAR may be nil; then you do not get access to the signal information.\n\
\n\
The value of the last BODY form is returned from the condition-case.\n\
See also the function `signal' for more info.")
  (args)
     Lisp_Object args;
{
  Lisp_Object val;
  struct catchtag c;
  struct handler h;
  register Lisp_Object tem;

  tem = Fcar (args);
  CHECK_SYMBOL (tem, 0);

  c.tag = Qnil;
  c.val = Qnil;
  c.backlist = backtrace_list;
  c.handlerlist = handlerlist;
  c.lisp_eval_depth = lisp_eval_depth;
  c.pdlcount = specpdl_ptr - specpdl;
  c.poll_suppress_count = poll_suppress_count;
  c.gcpro = gcprolist;
  if (_setjmp (c.jmp))
    {
Jim Blandy's avatar
Jim Blandy committed
987
      if (!NILP (h.var))
Jim Blandy's avatar
Jim Blandy committed
988 989 990 991 992 993 994 995 996 997
        specbind (h.var, Fcdr (c.val));
      val = Fprogn (Fcdr (Fcar (c.val)));
      unbind_to (c.pdlcount, Qnil);
      return val;
    }
  c.next = catchlist;
  catchlist = &c;
  h.var = Fcar (args);
  h.handler = Fcdr (Fcdr (args));
  
Jim Blandy's avatar
Jim Blandy committed
998
  for (val = h.handler; ! NILP (val); val = Fcdr (val))
Jim Blandy's avatar
Jim Blandy committed
999 1000
    {
      tem = Fcar (val);
Jim Blandy's avatar
Jim Blandy committed
1001
      if ((!NILP (tem)) &&
Jim Blandy's avatar
Jim Blandy committed
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101
	  (!CONSP (tem) || (XTYPE (XCONS (tem)->car) != Lisp_Symbol)))
	error ("Invalid condition handler", tem);
    }
  
  h.next = handlerlist;
  h.poll_suppress_count = poll_suppress_count;
  h.tag = &c;
  handlerlist = &h;

  val = Feval (Fcar (Fcdr (args)));
  catchlist = c.next;
  handlerlist = h.next;
  return val;
}

Lisp_Object
internal_condition_case (bfun, handlers, hfun)
     Lisp_Object (*bfun) ();
     Lisp_Object handlers;
     Lisp_Object (*hfun) ();
{
  Lisp_Object val;
  struct catchtag c;
  struct handler h;

  c.tag = Qnil;
  c.val = Qnil;
  c.backlist = backtrace_list;
  c.handlerlist = handlerlist;
  c.lisp_eval_depth = lisp_eval_depth;
  c.pdlcount = specpdl_ptr - specpdl;
  c.poll_suppress_count = poll_suppress_count;
  c.gcpro = gcprolist;
  if (_setjmp (c.jmp))
    {
      return (*hfun) (Fcdr (c.val));
    }
  c.next = catchlist;
  catchlist = &c;
  h.handler = handlers;
  h.var = Qnil;
  h.poll_suppress_count = poll_suppress_count;
  h.next = handlerlist;
  h.tag = &c;
  handlerlist = &h;

  val = (*bfun) ();
  catchlist = c.next;
  handlerlist = h.next;
  return val;
}

static Lisp_Object find_handler_clause ();

DEFUN ("signal", Fsignal, Ssignal, 2, 2, 0,
  "Signal an error.  Args are SIGNAL-NAME, and associated DATA.\n\
This function does not return.\n\n\
A signal name is a symbol with an `error-conditions' property\n\
that is a list of condition names.\n\
A handler for any of those names will get to handle this signal.\n\
The symbol `error' should normally be one of them.\n\
\n\
DATA should be a list.  Its elements are printed as part of the error message.\n\
If the signal is handled, DATA is made available to the handler.\n\
See also the function `condition-case'.")
  (sig, data)
     Lisp_Object sig, data;
{
  register struct handler *allhandlers = handlerlist;
  Lisp_Object conditions;
  extern int gc_in_progress;
  extern int waiting_for_input;
  Lisp_Object debugger_value;

  quit_error_check ();
  immediate_quit = 0;
  if (gc_in_progress || waiting_for_input)
    abort ();

  TOTALLY_UNBLOCK_INPUT;

  conditions = Fget (sig, Qerror_conditions);

  for (; handlerlist; handlerlist = handlerlist->next)
    {
      register Lisp_Object clause;
      clause = find_handler_clause (handlerlist->handler, conditions,
				    sig, data, &debugger_value);

#if 0 /* Most callers are not prepared to handle gc if this returns.
	 So, since this feature is not very useful, take it out.  */
      /* If have called debugger and user wants to continue,
	 just return nil.  */
      if (EQ (clause, Qlambda))
	return debugger_value;
#else
      if (EQ (clause, Qlambda))
	error ("Returning a value from an error is no longer supported");
#endif

Jim Blandy's avatar
Jim Blandy committed
1102
      if (!NILP (clause))
Jim Blandy's avatar
Jim Blandy committed
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123
	{
	  struct handler *h = handlerlist;
	  /* Restore the polling-suppression count.  */
	  if (h->poll_suppress_count > poll_suppress_count)
	    abort ();
	  while (h->poll_suppress_count < poll_suppress_count)
	    start_polling ();
	  handlerlist = allhandlers;
	  unbind_catch (h->tag);
	  h->tag->val = Fcons (clause, Fcons (sig, data));
	  _longjmp (h->tag->jmp, 1);
	}
    }

  handlerlist = allhandlers;
  /* If no handler is present now, try to run the debugger,
     and if that fails, throw to top level.  */
  find_handler_clause (Qerror, conditions, sig, data, &debugger_value);
  Fthrow (Qtop_level, Qt);
}

Roland McGrath's avatar
Roland McGrath committed
1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
/* Return nonzero iff LIST is a non-nil atom or
   a list containing one of CONDITIONS.  */

static int
wants_debugger (list, conditions)
     Lisp_Object list, conditions;
{
  static int looking = 0;

  if (looking)
    {
      /* We got an error while looking in LIST.  */
      looking = 0;
      return 1;
    }

  if (NULL (list))
    return 0;
  if (! CONSP (list))
    return 1;

  looking = 1;
  while (!NULL (conditions))
    {
      Lisp_Object tem;
      tem = Fmemq (XCONS (conditions)->car, list);
      if (! NULL (tem))
	{
	  looking = 0;
	  return 1;
	}
      conditions = XCONS (conditions)->cdr;
    }
}

/* Value of Qlambda means we have called debugger and user has continued.
   Store value returned from debugger into *DEBUGGER_VALUE_PTR.  */
Jim Blandy's avatar
Jim Blandy committed
1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174

static Lisp_Object
find_handler_clause (handlers, conditions, sig, data, debugger_value_ptr)
     Lisp_Object handlers, conditions, sig, data;
     Lisp_Object *debugger_value_ptr;
{
  register Lisp_Object h;
  register Lisp_Object tem;
  register Lisp_Object tem1;

  if (EQ (handlers, Qt))  /* t is used by handlers for all conditions, set up by C code.  */
    return Qt;
  if (EQ (handlers, Qerror))  /* error is used similarly, but means display a backtrace too */
    {
Roland McGrath's avatar
Roland McGrath committed
1175
      if (wants_debugger (Vstack_trace_on_error, conditions))
Jim Blandy's avatar
Jim Blandy committed
1176 1177
	internal_with_output_to_temp_buffer ("*Backtrace*", Fbacktrace, Qnil);
      if (!entering_debugger
Roland McGrath's avatar
Roland McGrath committed
1178 1179
	  && ((EQ (sig, Qquit) && debug_on_quit)
	      || wants_debugger (Vdebug_on_error, conditions)))
Jim Blandy's avatar
Jim Blandy committed
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196
	{
	  int count = specpdl_ptr - specpdl;
	  specbind (Qdebug_on_error, Qnil);
	  *debugger_value_ptr =
	    call_debugger (Fcons (Qerror,
				  Fcons (Fcons (sig, data),
					 Qnil)));
	  return unbind_to (count, Qlambda);
	}
      return Qt;
    }
  for (h = handlers; CONSP (h); h = Fcdr (h))
    {
      tem1 = Fcar (h);
      if (!CONSP (tem1))
	continue;
      tem = Fmemq (Fcar (tem1), conditions);
Jim Blandy's avatar
Jim Blandy committed
1197
      if (!NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238
        return tem1;
    }
  return Qnil;
}

/* dump an error message; called like printf */

/* VARARGS 1 */
void
error (m, a1, a2, a3)
     char *m;
{
  char buf[200];
  sprintf (buf, m, a1, a2, a3);

  while (1)
    Fsignal (Qerror, Fcons (build_string (buf), Qnil));
}

DEFUN ("commandp", Fcommandp, Scommandp, 1, 1, 0,
  "T if FUNCTION makes provisions for interactive calling.\n\
This means it contains a description for how to read arguments to give it.\n\
The value is nil for an invalid function or a symbol with no function\n\
definition.\n\
\n\
Interactively callable functions include strings and vectors (treated\n\
as keyboard macros), lambda-expressions that contain a top-level call\n\
to `interactive', autoload definitions made by `autoload' with non-nil\n\
fourth argument, and some of the built-in functions of Lisp.\n\
\n\
Also, a symbol satisfies `commandp' if its function definition does so.")
  (function)
     Lisp_Object function;
{
  register Lisp_Object fun;
  register Lisp_Object funcar;
  register Lisp_Object tem;
  register int i = 0;

  fun = function;

Jim Blandy's avatar
Jim Blandy committed
1239 1240 1241
  fun = indirect_function (fun);
  if (EQ (fun, Qunbound))
    return Qnil;
Jim Blandy's avatar
Jim Blandy committed
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360

  /* Emacs primitives are interactive if their DEFUN specifies an
     interactive spec.  */
  if (XTYPE (fun) == Lisp_Subr)
    {
      if (XSUBR (fun)->prompt)
	return Qt;
      else
	return Qnil;
    }

  /* Bytecode objects are interactive if they are long enough to
     have an element whose index is COMPILED_INTERACTIVE, which is
     where the interactive spec is stored.  */
  else if (XTYPE (fun) == Lisp_Compiled)
    return (XVECTOR (fun)->size > COMPILED_INTERACTIVE
	    ? Qt : Qnil);

  /* Strings and vectors are keyboard macros.  */
  if (XTYPE (fun) == Lisp_String
      || XTYPE (fun) == Lisp_Vector)
    return Qt;

  /* Lists may represent commands.  */
  if (!CONSP (fun))
    return Qnil;
  funcar = Fcar (fun);
  if (XTYPE (funcar) != Lisp_Symbol)
    return Fsignal (Qinvalid_function, Fcons (fun, Qnil));
  if (EQ (funcar, Qlambda))
    return Fassq (Qinteractive, Fcdr (Fcdr (fun)));
  if (EQ (funcar, Qmocklisp))
    return Qt;  /* All mocklisp functions can be called interactively */
  if (EQ (funcar, Qautoload))
    return Fcar (Fcdr (Fcdr (Fcdr (fun))));
  else
    return Qnil;
}

/* ARGSUSED */
DEFUN ("autoload", Fautoload, Sautoload, 2, 5, 0,
  "Define FUNCTION to autoload from FILE.\n\
FUNCTION is a symbol; FILE is a file name string to pass to `load'.\n\
Third arg DOCSTRING is documentation for the function.\n\
Fourth arg INTERACTIVE if non-nil says function can be called interactively.\n\
Fifth arg MACRO if non-nil says the function is really a macro.\n\
Third through fifth args give info about the real definition.\n\
They default to nil.\n\
If FUNCTION is already defined other than as an autoload,\n\
this does nothing and returns nil.")
  (function, file, docstring, interactive, macro)
     Lisp_Object function, file, docstring, interactive, macro;
{
#ifdef NO_ARG_ARRAY
  Lisp_Object args[4];
#endif

  CHECK_SYMBOL (function, 0);
  CHECK_STRING (file, 1);

  /* If function is defined and not as an autoload, don't override */
  if (!EQ (XSYMBOL (function)->function, Qunbound)
      && !(XTYPE (XSYMBOL (function)->function) == Lisp_Cons
	   && EQ (XCONS (XSYMBOL (function)->function)->car, Qautoload)))
    return Qnil;

#ifdef NO_ARG_ARRAY
  args[0] = file;
  args[1] = docstring;
  args[2] = interactive;
  args[3] = macro;

  return Ffset (function, Fcons (Qautoload, Flist (4, &args[0])));
#else /* NO_ARG_ARRAY */
  return Ffset (function, Fcons (Qautoload, Flist (4, &file)));
#endif /* not NO_ARG_ARRAY */
}

Lisp_Object
un_autoload (oldqueue)
     Lisp_Object oldqueue;
{
  register Lisp_Object queue, first, second;

  /* Queue to unwind is current value of Vautoload_queue.
     oldqueue is the shadowed value to leave in Vautoload_queue.  */
  queue = Vautoload_queue;
  Vautoload_queue = oldqueue;
  while (CONSP (queue))
    {
      first = Fcar (queue);
      second = Fcdr (first);
      first = Fcar (first);
      if (EQ (second, Qnil))
	Vfeatures = first;
      else
	Ffset (first, second);
      queue = Fcdr (queue);
    }
  return Qnil;
}

do_autoload (fundef, funname)
     Lisp_Object fundef, funname;
{
  int count = specpdl_ptr - specpdl;
  Lisp_Object fun, val;

  fun = funname;
  CHECK_SYMBOL (funname, 0);

  /* Value saved here is to be restored into Vautoload_queue */
  record_unwind_protect (un_autoload, Vautoload_queue);
  Vautoload_queue = Qt;
  Fload (Fcar (Fcdr (fundef)), Qnil, noninteractive ? Qt : Qnil, Qnil);
  /* Once loading finishes, don't undo it.  */
  Vautoload_queue = Qt;
  unbind_to (count, Qnil);

Jim Blandy's avatar
Jim Blandy committed
1361 1362
  fun = Findirect_function (fun);

Jim Blandy's avatar
Jim Blandy committed
1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383
  if (XTYPE (fun) == Lisp_Cons
      && EQ (XCONS (fun)->car, Qautoload))
    error ("Autoloading failed to define function %s",
	   XSYMBOL (funname)->name->data);
}

DEFUN ("eval", Feval, Seval, 1, 1, 0,
  "Evaluate FORM and return its value.")
  (form)
     Lisp_Object form;
{
  Lisp_Object fun, val, original_fun, original_args;
  Lisp_Object funcar;
  struct backtrace backtrace;
  struct gcpro gcpro1, gcpro2, gcpro3;

  if (XTYPE (form) == Lisp_Symbol)
    {
      if (EQ (Vmocklisp_arguments, Qt))
        return Fsymbol_value (form);
      val = Fsymbol_value (form);
Jim Blandy's avatar
Jim Blandy committed
1384
      if (NILP (val))
Jim Blandy's avatar
Jim Blandy committed
1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
	XFASTINT (val) = 0;
      else if (EQ (val, Qt))
	XFASTINT (val) = 1;
      return val;
    }
  if (!CONSP (form))
    return form;

  QUIT;
  if (consing_since_gc > gc_cons_threshold)
    {
      GCPRO1 (form);
      Fgarbage_collect ();
      UNGCPRO;
    }

  if (++lisp_eval_depth > max_lisp_eval_depth)
    {
      if (max_lisp_eval_depth < 100)
	max_lisp_eval_depth = 100;
      if (lisp_eval_depth > max_lisp_eval_depth)
	error ("Lisp nesting exceeds max-lisp-eval-depth");
    }

  original_fun = Fcar (form);
  original_args = Fcdr (form);

  backtrace.next = backtrace_list;
  backtrace_list = &backtrace;
  backtrace.function = &original_fun; /* This also protects them from gc */
  backtrace.args = &original_args;
  backtrace.nargs = UNEVALLED;
  backtrace.evalargs = 1;
  backtrace.debug_on_exit = 0;

  if (debug_on_next_call)
    do_debug_on_call (Qt);

  /* At this point, only original_fun and original_args
     have values that will be used below */
 retry:
Jim Blandy's avatar
Jim Blandy committed
1426
  fun = Findirect_function (original_fun);
Jim Blandy's avatar
Jim Blandy committed
1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460

  if (XTYPE (fun) == Lisp_Subr)
    {
      Lisp_Object numargs;
      Lisp_Object argvals[7];
      Lisp_Object args_left;
      register int i, maxargs;

      args_left = original_args;
      numargs = Flength (args_left);

      if (XINT (numargs) < XSUBR (fun)->min_args ||
	  (XSUBR (fun)->max_args >= 0 && XSUBR (fun)->max_args < XINT (numargs)))
	return Fsignal (Qwrong_number_of_arguments, Fcons (fun, Fcons (numargs, Qnil)));

      if (XSUBR (fun)->max_args == UNEVALLED)
	{
	  backtrace.evalargs = 0;
	  val = (*XSUBR (fun)->function) (args_left);
	  goto done;
	}

      if (XSUBR (fun)->max_args == MANY)
	{
	  /* Pass a vector of evaluated arguments */
	  Lisp_Object *vals;
	  register int argnum = 0;

	  vals = (Lisp_Object *) alloca (XINT (numargs) * sizeof (Lisp_Object));

	  GCPRO3 (args_left, fun, fun);
	  gcpro3.var = vals;
	  gcpro3.nvars = 0;

Jim Blandy's avatar
Jim Blandy committed
1461
	  while (!NILP (args_left))
Jim Blandy's avatar
Jim Blandy committed
1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
	    {
	      vals[argnum++] = Feval (Fcar (args_left));
	      args_left = Fcdr (args_left);
	      gcpro3.nvars = argnum;
	    }

	  backtrace.args = vals;
	  backtrace.nargs = XINT (numargs);

	  val = (*XSUBR (fun)->function) (XINT (numargs), vals);
Jim Blandy's avatar
Jim Blandy committed
1472
	  UNGCPRO;
Jim Blandy's avatar
Jim Blandy committed
1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520
	  goto done;
	}

      GCPRO3 (args_left, fun, fun);
      gcpro3.var = argvals;
      gcpro3.nvars = 0;

      maxargs = XSUBR (fun)->max_args;
      for (i = 0; i < maxargs; args_left = Fcdr (args_left))
	{
	  argvals[i] = Feval (Fcar (args_left));
	  gcpro3.nvars = ++i;
	}

      UNGCPRO;

      backtrace.args = argvals;
      backtrace.nargs = XINT (numargs);

      switch (i)
	{
	case 0:
	  val = (*XSUBR (fun)->function) ();
	  goto done;
	case 1:
	  val = (*XSUBR (fun)->function) (argvals[0]);
	  goto done;
	case 2:
	  val = (*XSUBR (fun)->function) (argvals[0], argvals[1]);
	  goto done;
	case 3:
	  val = (*XSUBR (fun)->function) (argvals[0], argvals[1],
					  argvals[2]);
	  goto done;
	case 4:
	  val = (*XSUBR (fun)->function) (argvals[0], argvals[1],
					  argvals[2], argvals[3]);
	  goto done;
	case 5:
	  val = (*XSUBR (fun)->function) (argvals[0], argvals[1], argvals[2],
					  argvals[3], argvals[4]);
	  goto done;
	case 6:
	  val = (*XSUBR (fun)->function) (argvals[0], argvals[1], argvals[2],
					  argvals[3], argvals[4], argvals[5]);
	  goto done;

	default:
Jim Blandy's avatar
Jim Blandy committed
1521 1522 1523 1524 1525
	  /* Someone has created a subr that takes more arguments than
	     is supported by this code.  We need to either rewrite the
	     subr to use a different argument protocol, or add more
	     cases to this switch.  */
	  abort ();
Jim Blandy's avatar
Jim Blandy committed
1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553
	}
    }
  if (XTYPE (fun) == Lisp_Compiled)
    val = apply_lambda (fun, original_args, 1);
  else
    {
      if (!CONSP (fun))
	return Fsignal (Qinvalid_function, Fcons (fun, Qnil));
      funcar = Fcar (fun);
      if (XTYPE (funcar) != Lisp_Symbol)
	return Fsignal (Qinvalid_function, Fcons (fun, Qnil));
      if (EQ (funcar, Qautoload))
	{
	  do_autoload (fun, original_fun);
	  goto retry;
	}
      if (EQ (funcar, Qmacro))
	val = Feval (apply1 (Fcdr (fun), original_args));
      else if (EQ (funcar, Qlambda))
	val = apply_lambda (fun, original_args, 1);
      else if (EQ (funcar, Qmocklisp))
	val = ml_apply (fun, original_args);
      else
	return Fsignal (Qinvalid_function, Fcons (fun, Qnil));
    }
 done:
  if (!EQ (Vmocklisp_arguments, Qt))
    {
Jim Blandy's avatar
Jim Blandy committed
1554
      if (NILP (val))
Jim Blandy's avatar
Jim Blandy committed
1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	XFASTINT (val) = 0;
      else if (EQ (val, Qt))
	XFASTINT (val) = 1;
    }
  lisp_eval_depth--;
  if (backtrace.debug_on_exit)
    val = call_debugger (Fcons (Qexit, Fcons (val, Qnil)));
  backtrace_list = backtrace.next;
  return val;
}

DEFUN ("apply", Fapply, Sapply, 2, MANY, 0,
  "Call FUNCTION with our remaining args, using our last arg as list of args.\n\
Thus, (apply '+ 1 2 '(3 4)) returns 10.")
  (nargs, args)
     int nargs;
     Lisp_Object *args;
{
  register int i, numargs;
  register Lisp_Object spread_arg;
  register Lisp_Object *funcall_args;
  Lisp_Object fun;
Jim Blandy's avatar
Jim Blandy committed
1577
  struct gcpro gcpro1;
Jim Blandy's avatar
Jim Blandy committed
1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593

  fun = args [0];
  funcall_args = 0;
  spread_arg = args [nargs - 1];
  CHECK_LIST (spread_arg, nargs);
  
  numargs = XINT (Flength (spread_arg));

  if (numargs == 0)
    return Ffuncall (nargs - 1, args);
  else if (numargs == 1)
    {
      args [nargs - 1] = XCONS (spread_arg)->car;
      return Ffuncall (nargs, args);
    }

Jim Blandy's avatar
Jim Blandy committed
1594
  numargs += nargs - 2;
Jim Blandy's avatar
Jim Blandy committed
1595

Jim Blandy's avatar
Jim Blandy committed
1596 1597
  fun = indirect_function (fun);
  if (EQ (fun, Qunbound))
Jim Blandy's avatar
Jim Blandy committed
1598
    {
Jim Blandy's avatar
Jim Blandy committed
1599 1600 1601
      /* Let funcall get the error */
      fun = args[0];
      goto funcall;
Jim Blandy's avatar
Jim Blandy committed
1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616
    }

  if (XTYPE (fun) == Lisp_Subr)
    {
      if (numargs < XSUBR (fun)->min_args
	  || (XSUBR (fun)->max_args >= 0 && XSUBR (fun)->max_args < numargs))
	goto funcall;		/* Let funcall get the error */
      else if (XSUBR (fun)->max_args > numargs)
	{
	  /* Avoid making funcall cons up a yet another new vector of arguments
	     by explicitly supplying nil's for optional values */
	  funcall_args = (Lisp_Object *) alloca ((1 + XSUBR (fun)->max_args)
						 * sizeof (Lisp_Object));
	  for (i = numargs; i < XSUBR (fun)->max_args;)
	    funcall_args[++i] = Qnil;
Jim Blandy's avatar
Jim Blandy committed
1617 1618
	  GCPRO1 (*funcall_args);
	  gcpro1.nvars = 1 + XSUBR (fun)->max_args;
Jim Blandy's avatar
Jim Blandy committed
1619 1620 1621 1622 1623 1624
	}
    }
 funcall:
  /* We add 1 to numargs because funcall_args includes the
     function itself as well as its arguments.  */
  if (!funcall_args)
Jim Blandy's avatar
Jim Blandy committed
1625 1626 1627 1628 1629 1630 1631
    {
      funcall_args = (Lisp_Object *) alloca ((1 + numargs)
					     * sizeof (Lisp_Object));
      GCPRO1 (*funcall_args);
      gcpro1.nvars = 1 + numargs;
    }

Jim Blandy's avatar
Jim Blandy committed
1632 1633 1634 1635
  bcopy (args, funcall_args, nargs * sizeof (Lisp_Object));
  /* Spread the last arg we got.  Its first element goes in
     the slot that it used to occupy, hence this value of I.  */
  i = nargs - 1;
Jim Blandy's avatar
Jim Blandy committed
1636
  while (!NILP (spread_arg))
Jim Blandy's avatar
Jim Blandy committed
1637 1638 1639 1640
    {
      funcall_args [i++] = XCONS (spread_arg)->car;
      spread_arg = XCONS (spread_arg)->cdr;
    }
Jim Blandy's avatar
Jim Blandy committed
1641 1642

  RETURN_UNGCPRO (Ffuncall (gcpro1.nvars, funcall_args));
Jim Blandy's avatar
Jim Blandy committed
1643 1644 1645 1646 1647 1648 1649
}

/* Apply fn to arg */
Lisp_Object
apply1 (fn, arg)
     Lisp_Object fn, arg;
{
Jim Blandy's avatar
Jim Blandy committed
1650 1651 1652
  struct gcpro gcpro1;

  GCPRO1 (fn);
Jim Blandy's avatar
Jim Blandy committed
1653
  if (NILP (arg))
Jim Blandy's avatar
Jim Blandy committed
1654 1655
    RETURN_UNGCPRO (Ffuncall (1, &fn));
  gcpro1.nvars = 2;
Jim Blandy's avatar
Jim Blandy committed
1656 1657 1658 1659 1660
#ifdef NO_ARG_ARRAY
  {
    Lisp_Object args[2];
    args[0] = fn;
    args[1] = arg;
Jim Blandy's avatar
Jim Blandy committed
1661 1662
    gcpro1.var = args;
    RETURN_UNGCPRO (Fapply (2, args));
Jim Blandy's avatar
Jim Blandy committed
1663 1664
  }
#else /* not NO_ARG_ARRAY */
Jim Blandy's avatar
Jim Blandy committed
1665
  RETURN_UNGCPRO (Fapply (2, &fn));
Jim Blandy's avatar
Jim Blandy committed
1666 1667 1668 1669 1670 1671 1672 1673
#endif /* not NO_ARG_ARRAY */
}

/* Call function fn on no arguments */
Lisp_Object
call0 (fn)
     Lisp_Object fn;
{
Jim Blandy's avatar
Jim Blandy committed
1674 1675 1676 1677
  struct gcpro gcpro1;

  GCPRO1 (fn);
  RETURN_UNGCPRO (Ffuncall (1, &fn));
Jim Blandy's avatar
Jim Blandy committed
1678 1679 1680 1681 1682 1683 1684 1685
}

/* Call function fn with argument arg */
/* ARGSUSED */
Lisp_Object
call1 (fn, arg)
     Lisp_Object fn, arg;
{
Jim Blandy's avatar
Jim Blandy committed
1686
  struct gcpro gcpro1;
Jim Blandy's avatar
Jim Blandy committed
1687
#ifdef NO_ARG_ARRAY
Jim Blandy's avatar
Jim Blandy committed
1688 1689
  Lisp_Object args[2];  

Jim Blandy's avatar
Jim Blandy committed
1690 1691
  args[0] = fn;
  args[1] =