Trailing whitespace deleted.

[bpt/emacs.git] / src / lread.c

/* Lisp parsing and input streams.
   Copyright (C) 1985, 86, 87, 88, 89, 93, 94, 95, 97, 98, 99, 2000, 2001
      Free Software Foundation, Inc.

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 2, 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, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <errno.h>
#include "lisp.h"
#include "intervals.h"
#include "buffer.h"
#include "charset.h"
#include <epaths.h>
#include "commands.h"
#include "keyboard.h"
#include "termhooks.h"
#include "coding.h"

#ifdef lint
#include <sys/inode.h>
#endif /* lint */

#ifdef MSDOS
#if __DJGPP__ < 2
#include <unistd.h>     /* to get X_OK */
#endif
#include "msdos.h"
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifndef X_OK
#define X_OK 01
#endif

#include <math.h>

#ifdef HAVE_SETLOCALE
#include <locale.h>
#endif /* HAVE_SETLOCALE */

#ifndef O_RDONLY
#define O_RDONLY 0
#endif

#ifdef HAVE_FSEEKO
#define file_offset off_t
#define file_tell ftello
#else
#define file_offset long
#define file_tell ftell
#endif

#ifndef USE_CRT_DLL
extern int errno;
#endif

Lisp_Object Qread_char, Qget_file_char, Qstandard_input, Qcurrent_load_list;
Lisp_Object Qvariable_documentation, Vvalues, Vstandard_input, Vafter_load_alist;
Lisp_Object Qascii_character, Qload, Qload_file_name;
Lisp_Object Qbackquote, Qcomma, Qcomma_at, Qcomma_dot, Qfunction;
Lisp_Object Qinhibit_file_name_operation;

extern Lisp_Object Qevent_symbol_element_mask;
extern Lisp_Object Qfile_exists_p;

/* non-zero if inside `load' */
int load_in_progress;

/* Directory in which the sources were found.  */
Lisp_Object Vsource_directory;

/* Search path and suffixes for files to be loaded. */
Lisp_Object Vload_path, Vload_suffixes, default_suffixes;

/* File name of user's init file.  */
Lisp_Object Vuser_init_file;

/* This is the user-visible association list that maps features to
   lists of defs in their load files. */
Lisp_Object Vload_history;

/* This is used to build the load history. */
Lisp_Object Vcurrent_load_list;

/* List of files that were preloaded.  */
Lisp_Object Vpreloaded_file_list;

/* Name of file actually being read by `load'.  */
Lisp_Object Vload_file_name;

/* Function to use for reading, in `load' and friends.  */
Lisp_Object Vload_read_function;

/* The association list of objects read with the #n=object form.
   Each member of the list has the form (n . object), and is used to
   look up the object for the corresponding #n# construct.
   It must be set to nil before all top-level calls to read0.  */
Lisp_Object read_objects;

/* Nonzero means load should forcibly load all dynamic doc strings.  */
static int load_force_doc_strings;

/* Nonzero means read should convert strings to unibyte.  */
static int load_convert_to_unibyte;

/* Function to use for loading an Emacs lisp source file (not
   compiled) instead of readevalloop.  */
Lisp_Object Vload_source_file_function;

/* List of all DEFVAR_BOOL variables.  Used by the byte optimizer.  */
Lisp_Object Vbyte_boolean_vars;

/* Whether or not to add a `read-positions' property to symbols
   read. */
Lisp_Object Vread_with_symbol_positions;

/* List of (SYMBOL . POSITION) accumulated so far. */
Lisp_Object Vread_symbol_positions_list;

/* List of descriptors now open for Fload.  */
static Lisp_Object load_descriptor_list;

/* File for get_file_char to read from.  Use by load.  */
static FILE *instream;

/* When nonzero, read conses in pure space */
static int read_pure;

/* For use within read-from-string (this reader is non-reentrant!!)  */
static int read_from_string_index;
static int read_from_string_index_byte;
static int read_from_string_limit;

/* Number of bytes left to read in the buffer character
   that `readchar' has already advanced over.  */
static int readchar_backlog;
/* Number of characters read in the current call to Fread or
   Fread_from_string. */
static int readchar_count;

/* This contains the last string skipped with #@.  */
static char *saved_doc_string;
/* Length of buffer allocated in saved_doc_string.  */
static int saved_doc_string_size;
/* Length of actual data in saved_doc_string.  */
static int saved_doc_string_length;
/* This is the file position that string came from.  */
static file_offset saved_doc_string_position;

/* This contains the previous string skipped with #@.
   We copy it from saved_doc_string when a new string
   is put in saved_doc_string.  */
static char *prev_saved_doc_string;
/* Length of buffer allocated in prev_saved_doc_string.  */
static int prev_saved_doc_string_size;
/* Length of actual data in prev_saved_doc_string.  */
static int prev_saved_doc_string_length;
/* This is the file position that string came from.  */
static file_offset prev_saved_doc_string_position;

/* Nonzero means inside a new-style backquote
   with no surrounding parentheses.
   Fread initializes this to zero, so we need not specbind it
   or worry about what happens to it when there is an error.  */
static int new_backquote_flag;

/* A list of file names for files being loaded in Fload.  Used to
   check for recursive loads.  */

static Lisp_Object Vloads_in_progress;

/* Non-zero means load dangerous compiled Lisp files.  */

int load_dangerous_libraries;

/* A regular expression used to detect files compiled with Emacs.  */

static Lisp_Object Vbytecomp_version_regexp;

static void to_multibyte P_ ((char **, char **, int *));
static void readevalloop P_ ((Lisp_Object, FILE*, Lisp_Object,
                              Lisp_Object (*) (), int,
                              Lisp_Object, Lisp_Object));
static Lisp_Object load_unwind P_ ((Lisp_Object));
static Lisp_Object load_descriptor_unwind P_ ((Lisp_Object));

\f
/* Handle unreading and rereading of characters.
   Write READCHAR to read a character,
   UNREAD(c) to unread c to be read again.

   The READCHAR and UNREAD macros are meant for reading/unreading a
   byte code; they do not handle multibyte characters.  The caller
   should manage them if necessary.
   
   [ Actually that seems to be a lie; READCHAR will definitely read
     multibyte characters from buffer sources, at least.  Is the
     comment just out of date?
     -- Colin Walters <walters@gnu.org>, 22 May 2002 16:36:50 -0400 ]
 */

#define READCHAR readchar (readcharfun)
#define UNREAD(c) unreadchar (readcharfun, c)

static int
readchar (readcharfun)
     Lisp_Object readcharfun;
{
  Lisp_Object tem;
  register int c;

  readchar_count++;
  
  if (BUFFERP (readcharfun))
    {
      register struct buffer *inbuffer = XBUFFER (readcharfun);

      int pt_byte = BUF_PT_BYTE (inbuffer);
      int orig_pt_byte = pt_byte;

      if (readchar_backlog > 0)
        /* We get the address of the byte just passed,
           which is the last byte of the character.
           The other bytes in this character are consecutive with it,
           because the gap can't be in the middle of a character.  */
        return *(BUF_BYTE_ADDRESS (inbuffer, BUF_PT_BYTE (inbuffer) - 1)
                 - --readchar_backlog);

      if (pt_byte >= BUF_ZV_BYTE (inbuffer))
        return -1;

      readchar_backlog = -1;

      if (! NILP (inbuffer->enable_multibyte_characters))
        {
          /* Fetch the character code from the buffer.  */
          unsigned char *p = BUF_BYTE_ADDRESS (inbuffer, pt_byte);
          BUF_INC_POS (inbuffer, pt_byte);
          c = STRING_CHAR (p, pt_byte - orig_pt_byte);
        }
      else
        {
          c = BUF_FETCH_BYTE (inbuffer, pt_byte);
          pt_byte++;
        }
      SET_BUF_PT_BOTH (inbuffer, BUF_PT (inbuffer) + 1, pt_byte);

      return c;
    }
  if (MARKERP (readcharfun))
    {
      register struct buffer *inbuffer = XMARKER (readcharfun)->buffer;

      int bytepos = marker_byte_position (readcharfun);
      int orig_bytepos = bytepos;

      if (readchar_backlog > 0)
        /* We get the address of the byte just passed,
           which is the last byte of the character.
           The other bytes in this character are consecutive with it,
           because the gap can't be in the middle of a character.  */
        return *(BUF_BYTE_ADDRESS (inbuffer, XMARKER (readcharfun)->bytepos - 1)
                 - --readchar_backlog);

      if (bytepos >= BUF_ZV_BYTE (inbuffer))
        return -1;

      readchar_backlog = -1;

      if (! NILP (inbuffer->enable_multibyte_characters))
        {
          /* Fetch the character code from the buffer.  */
          unsigned char *p = BUF_BYTE_ADDRESS (inbuffer, bytepos);
          BUF_INC_POS (inbuffer, bytepos);
          c = STRING_CHAR (p, bytepos - orig_bytepos);
        }
      else
        {
          c = BUF_FETCH_BYTE (inbuffer, bytepos);
          bytepos++;
        }

      XMARKER (readcharfun)->bytepos = bytepos;
      XMARKER (readcharfun)->charpos++;

      return c;
    }

  if (EQ (readcharfun, Qlambda))
    return read_bytecode_char (0);

  if (EQ (readcharfun, Qget_file_char))
    {
      c = getc (instream);
#ifdef EINTR
      /* Interrupted reads have been observed while reading over the network */
      while (c == EOF && ferror (instream) && errno == EINTR)
        {
          clearerr (instream);
          c = getc (instream);
        }
#endif
      return c;
    }

  if (STRINGP (readcharfun))
    {
      if (read_from_string_index >= read_from_string_limit)
        c = -1;
      else
        FETCH_STRING_CHAR_ADVANCE (c, readcharfun,
                                   read_from_string_index,
                                   read_from_string_index_byte);

      return c;
    }

  tem = call0 (readcharfun);

  if (NILP (tem))
    return -1;
  return XINT (tem);
}

/* Unread the character C in the way appropriate for the stream READCHARFUN.
   If the stream is a user function, call it with the char as argument.  */

static void
unreadchar (readcharfun, c)
     Lisp_Object readcharfun;
     int c;
{
  readchar_count--;
  if (c == -1)
    /* Don't back up the pointer if we're unreading the end-of-input mark,
       since readchar didn't advance it when we read it.  */
    ;
  else if (BUFFERP (readcharfun))
    {
      struct buffer *b = XBUFFER (readcharfun);
      int bytepos = BUF_PT_BYTE (b);

      if (readchar_backlog >= 0)
        readchar_backlog++;
      else
        {
          BUF_PT (b)--;
          if (! NILP (b->enable_multibyte_characters))
            BUF_DEC_POS (b, bytepos);
          else
            bytepos--;

          BUF_PT_BYTE (b) = bytepos;
        }
    }
  else if (MARKERP (readcharfun))
    {
      struct buffer *b = XMARKER (readcharfun)->buffer;
      int bytepos = XMARKER (readcharfun)->bytepos;

      if (readchar_backlog >= 0)
        readchar_backlog++;
      else
        {
          XMARKER (readcharfun)->charpos--;
          if (! NILP (b->enable_multibyte_characters))
            BUF_DEC_POS (b, bytepos);
          else
            bytepos--;

          XMARKER (readcharfun)->bytepos = bytepos;
        }
    }
  else if (STRINGP (readcharfun))
    {
      read_from_string_index--;
      read_from_string_index_byte
        = string_char_to_byte (readcharfun, read_from_string_index);
    }
  else if (EQ (readcharfun, Qlambda))
    read_bytecode_char (1);
  else if (EQ (readcharfun, Qget_file_char))
    ungetc (c, instream);
  else
    call1 (readcharfun, make_number (c));
}

static Lisp_Object read_internal_start P_ ((Lisp_Object, Lisp_Object,
                                            Lisp_Object));
static Lisp_Object read0 P_ ((Lisp_Object));
static Lisp_Object read1 P_ ((Lisp_Object, int *, int)); 

static Lisp_Object read_list P_ ((int, Lisp_Object));
static Lisp_Object read_vector P_ ((Lisp_Object, int));
static int read_multibyte P_ ((int, Lisp_Object));

static Lisp_Object substitute_object_recurse P_ ((Lisp_Object, Lisp_Object,
                                                  Lisp_Object));
static void substitute_object_in_subtree P_ ((Lisp_Object,
                                              Lisp_Object));
static void substitute_in_interval P_ ((INTERVAL, Lisp_Object));

\f
/* Get a character from the tty.  */

extern Lisp_Object read_char ();

/* Read input events until we get one that's acceptable for our purposes.

   If NO_SWITCH_FRAME is non-zero, switch-frame events are stashed
   until we get a character we like, and then stuffed into
   unread_switch_frame.

   If ASCII_REQUIRED is non-zero, we check function key events to see
   if the unmodified version of the symbol has a Qascii_character
   property, and use that character, if present.

   If ERROR_NONASCII is non-zero, we signal an error if the input we
   get isn't an ASCII character with modifiers.  If it's zero but
   ASCII_REQUIRED is non-zero, we just re-read until we get an ASCII
   character.

   If INPUT_METHOD is nonzero, we invoke the current input method
   if the character warrants that.  */

Lisp_Object
read_filtered_event (no_switch_frame, ascii_required, error_nonascii,
                     input_method)
     int no_switch_frame, ascii_required, error_nonascii, input_method;
{
  register Lisp_Object val, delayed_switch_frame;

#ifdef HAVE_WINDOW_SYSTEM
  if (display_hourglass_p)
    cancel_hourglass ();
#endif
  
  delayed_switch_frame = Qnil;

  /* Read until we get an acceptable event.  */
 retry:
  val = read_char (0, 0, 0,
                   (input_method ? Qnil : Qt),
                   0);

  if (BUFFERP (val))
    goto retry;

  /* switch-frame events are put off until after the next ASCII
     character.  This is better than signaling an error just because
     the last characters were typed to a separate minibuffer frame,
     for example.  Eventually, some code which can deal with
     switch-frame events will read it and process it.  */
  if (no_switch_frame
      && EVENT_HAS_PARAMETERS (val)
      && EQ (EVENT_HEAD (val), Qswitch_frame))
    {
      delayed_switch_frame = val;
      goto retry;
    }

  if (ascii_required)
    {
      /* Convert certain symbols to their ASCII equivalents.  */
      if (SYMBOLP (val))
        {
          Lisp_Object tem, tem1;
          tem = Fget (val, Qevent_symbol_element_mask);
          if (!NILP (tem))
            {
              tem1 = Fget (Fcar (tem), Qascii_character);
              /* Merge this symbol's modifier bits
                 with the ASCII equivalent of its basic code.  */
              if (!NILP (tem1))
                XSETFASTINT (val, XINT (tem1) | XINT (Fcar (Fcdr (tem))));
            }
        }
          
      /* If we don't have a character now, deal with it appropriately.  */
      if (!INTEGERP (val))
        {
          if (error_nonascii)
            {
              Vunread_command_events = Fcons (val, Qnil);
              error ("Non-character input-event");
            }
          else
            goto retry;
        }
    }

  if (! NILP (delayed_switch_frame))
    unread_switch_frame = delayed_switch_frame;

#if 0

#ifdef HAVE_WINDOW_SYSTEM
  if (display_hourglass_p)
    start_hourglass ();
#endif

#endif

  return val;
}

DEFUN ("read-char", Fread_char, Sread_char, 0, 2, 0,
       doc: /* Read a character from the command input (keyboard or macro).
It is returned as a number.
If the user generates an event which is not a character (i.e. a mouse
click or function key event), `read-char' signals an error.  As an
exception, switch-frame events are put off until non-ASCII events can
be read.
If you want to read non-character events, or ignore them, call
`read-event' or `read-char-exclusive' instead.

If the optional argument PROMPT is non-nil, display that as a prompt.
If the optional argument INHERIT-INPUT-METHOD is non-nil and some
input method is turned on in the current buffer, that input method
is used for reading a character.  */)
     (prompt, inherit_input_method)
     Lisp_Object prompt, inherit_input_method;
{
  if (! NILP (prompt))
    message_with_string ("%s", prompt, 0);
  return read_filtered_event (1, 1, 1, ! NILP (inherit_input_method));
}

DEFUN ("read-event", Fread_event, Sread_event, 0, 2, 0,
       doc: /* Read an event object from the input stream.
If the optional argument PROMPT is non-nil, display that as a prompt.
If the optional argument INHERIT-INPUT-METHOD is non-nil and some
input method is turned on in the current buffer, that input method
is used for reading a character.  */)
     (prompt, inherit_input_method)
     Lisp_Object prompt, inherit_input_method;
{
  if (! NILP (prompt))
    message_with_string ("%s", prompt, 0);
  return read_filtered_event (0, 0, 0, ! NILP (inherit_input_method));
}

DEFUN ("read-char-exclusive", Fread_char_exclusive, Sread_char_exclusive, 0, 2, 0,
       doc: /* Read a character from the command input (keyboard or macro).
It is returned as a number.  Non-character events are ignored.

If the optional argument PROMPT is non-nil, display that as a prompt.
If the optional argument INHERIT-INPUT-METHOD is non-nil and some
input method is turned on in the current buffer, that input method
is used for reading a character.  */)
     (prompt, inherit_input_method)
     Lisp_Object prompt, inherit_input_method;
{
  if (! NILP (prompt))
    message_with_string ("%s", prompt, 0);
  return read_filtered_event (1, 1, 0, ! NILP (inherit_input_method));
}

DEFUN ("get-file-char", Fget_file_char, Sget_file_char, 0, 0, 0,
       doc: /* Don't use this yourself.  */)
     ()
{
  register Lisp_Object val;
  XSETINT (val, getc (instream));
  return val;
}


\f
/* Value is non-zero if the file asswociated with file descriptor FD
   is a compiled Lisp file that's safe to load.  Only files compiled
   with Emacs are safe to load.  Files compiled with XEmacs can lead
   to a crash in Fbyte_code because of an incompatible change in the
   byte compiler.  */

static int
safe_to_load_p (fd)
     int fd;
{
  char buf[512];
  int nbytes, i;
  int safe_p = 1;

  /* Read the first few bytes from the file, and look for a line
     specifying the byte compiler version used.  */
  nbytes = emacs_read (fd, buf, sizeof buf - 1);
  if (nbytes > 0)
    {
      buf[nbytes] = '\0';

      /* Skip to the next newline, skipping over the initial `ELC'
         with NUL bytes following it.  */
      for (i = 0; i < nbytes && buf[i] != '\n'; ++i)
        ;

      if (i < nbytes
          && fast_c_string_match_ignore_case (Vbytecomp_version_regexp,
                                              buf + i) < 0)
        safe_p = 0;
    }

  lseek (fd, 0, SEEK_SET);
  return safe_p;
}


/* Callback for record_unwind_protect.  Restore the old load list OLD,
   after loading a file successfully.  */

static Lisp_Object
record_load_unwind (old)
     Lisp_Object old;
{
  return Vloads_in_progress = old;
}

/* This handler function is used via internal_condition_case_1.  */

static Lisp_Object
load_error_handler (data)
     Lisp_Object data;
{
  return Qnil;
}

DEFUN ("load", Fload, Sload, 1, 5, 0,
       doc: /* Execute a file of Lisp code named FILE.
First try FILE with `.elc' appended, then try with `.el',
 then try FILE unmodified (the exact suffixes are determined by
`load-suffixes').  Environment variable references in FILE
 are replaced with their values by calling `substitute-in-file-name'.
This function searches the directories in `load-path'.
If optional second arg NOERROR is non-nil,
 report no error if FILE doesn't exist.
Print messages at start and end of loading unless
 optional third arg NOMESSAGE is non-nil.
If optional fourth arg NOSUFFIX is non-nil, don't try adding
 suffixes `.elc' or `.el' to the specified name FILE.
If optional fifth arg MUST-SUFFIX is non-nil, insist on
 the suffix `.elc' or `.el'; don't accept just FILE unless
 it ends in one of those suffixes or includes a directory name.
Return t if file exists.  */)
     (file, noerror, nomessage, nosuffix, must_suffix)
     Lisp_Object file, noerror, nomessage, nosuffix, must_suffix;
{
  register FILE *stream;
  register int fd = -1;
  register Lisp_Object lispstream;
  int count = SPECPDL_INDEX ();
  Lisp_Object temp;
  struct gcpro gcpro1;
  Lisp_Object found, efound;
  /* 1 means we printed the ".el is newer" message.  */
  int newer = 0;
  /* 1 means we are loading a compiled file.  */
  int compiled = 0;
  Lisp_Object handler;
  int safe_p = 1;
  char *fmode = "r";
#ifdef DOS_NT
  fmode = "rt";
#endif /* DOS_NT */

  CHECK_STRING (file);

  /* If file name is magic, call the handler.  */
  /* This shouldn't be necessary any more now that `openp' handles it right.
    handler = Ffind_file_name_handler (file, Qload);
    if (!NILP (handler))
      return call5 (handler, Qload, file, noerror, nomessage, nosuffix); */

  /* Do this after the handler to avoid
     the need to gcpro noerror, nomessage and nosuffix.
     (Below here, we care only whether they are nil or not.)
     The presence of this call is the result of a historical accident:
     it used to be in every file-operations and when it got removed
     everywhere, it accidentally stayed here.  Since then, enough people
     supposedly have things like (load "$PROJECT/foo.el") in their .emacs
     that it seemed risky to remove.  */
  if (! NILP (noerror))
    {
      file = internal_condition_case_1 (Fsubstitute_in_file_name, file,
                                        Qt, load_error_handler);
      if (NILP (file))
        return Qnil;
    }
  else
    file = Fsubstitute_in_file_name (file);
    

  /* Avoid weird lossage with null string as arg,
     since it would try to load a directory as a Lisp file */
  if (SCHARS (file) > 0)
    {
      int size = SBYTES (file);
      Lisp_Object tmp[2];

      GCPRO1 (file);

      if (! NILP (must_suffix))
        {
          /* Don't insist on adding a suffix if FILE already ends with one.  */
          if (size > 3
              && !strcmp (SDATA (file) + size - 3, ".el"))
            must_suffix = Qnil;
          else if (size > 4
                   && !strcmp (SDATA (file) + size - 4, ".elc"))
            must_suffix = Qnil;
          /* Don't insist on adding a suffix
             if the argument includes a directory name.  */
          else if (! NILP (Ffile_name_directory (file)))
            must_suffix = Qnil;
        }

      fd = openp (Vload_path, file,
                  (!NILP (nosuffix) ? Qnil
                   : !NILP (must_suffix) ? Vload_suffixes
                   : Fappend (2, (tmp[0] = Vload_suffixes,
                                  tmp[1] = default_suffixes,
                                  tmp))),
                  &found, Qnil);
      UNGCPRO;
    }

  if (fd == -1)
    {
      if (NILP (noerror))
        Fsignal (Qfile_error, Fcons (build_string ("Cannot open load file"),
                                     Fcons (file, Qnil)));
      else
        return Qnil;
    }

  /* Tell startup.el whether or not we found the user's init file.  */
  if (EQ (Qt, Vuser_init_file))
    Vuser_init_file = found;

  /* If FD is -2, that means openp found a magic file.  */
  if (fd == -2)
    {
      if (NILP (Fequal (found, file)))
        /* If FOUND is a different file name from FILE,
           find its handler even if we have already inhibited
           the `load' operation on FILE.  */
        handler = Ffind_file_name_handler (found, Qt);
      else
        handler = Ffind_file_name_handler (found, Qload);
      if (! NILP (handler))
        return call5 (handler, Qload, found, noerror, nomessage, Qt);
    }

  /* Check if we're stuck in a recursive load cycle.

     2000-09-21: It's not possible to just check for the file loaded
     being a member of Vloads_in_progress.  This fails because of the
     way the byte compiler currently works; `provide's are not
     evaluted, see font-lock.el/jit-lock.el as an example.  This
     leads to a certain amount of ``normal'' recursion.

     Also, just loading a file recursively is not always an error in
     the general case; the second load may do something different.  */
  {
    int count = 0;
    Lisp_Object tem;
    for (tem = Vloads_in_progress; CONSP (tem); tem = XCDR (tem))
      if (!NILP (Fequal (found, XCAR (tem))))
        count++;
    if (count > 3)
      Fsignal (Qerror, Fcons (build_string ("Recursive load"),
                              Fcons (found, Vloads_in_progress)));
    record_unwind_protect (record_load_unwind, Vloads_in_progress);
    Vloads_in_progress = Fcons (found, Vloads_in_progress);
  }

  if (!bcmp (SDATA (found) + SBYTES (found) - 4,
             ".elc", 4))
    /* Load .elc files directly, but not when they are
       remote and have no handler!  */
    {
      if (fd != -2)
        {
          struct stat s1, s2;
          int result;

          if (!safe_to_load_p (fd))
            {
              safe_p = 0;
              if (!load_dangerous_libraries)
                {
                  if (fd >= 0)
                    emacs_close (fd);
                  error ("File `%s' was not compiled in Emacs",
                         SDATA (found));
                }
              else if (!NILP (nomessage))
                message_with_string ("File `%s' not compiled in Emacs", found, 1);
            }

          compiled = 1;

          GCPRO1 (efound);
          efound = ENCODE_FILE (found);

#ifdef DOS_NT
          fmode = "rb";
#endif /* DOS_NT */
          stat ((char *)SDATA (efound), &s1);
          SSET (efound, SBYTES (efound) - 1, 0);
          result = stat ((char *)SDATA (efound), &s2);
          SSET (efound, SBYTES (efound) - 1, 'c');
          UNGCPRO;

          if (result >= 0 && (unsigned) s1.st_mtime < (unsigned) s2.st_mtime)
            {
              /* Make the progress messages mention that source is newer.  */
              newer = 1;

              /* If we won't print another message, mention this anyway.  */
              if (!NILP (nomessage))
                {
                  Lisp_Object file;
                  file = Fsubstring (found, make_number (0), make_number (-1));
                  message_with_string ("Source file `%s' newer than byte-compiled file",
                                       file, STRING_MULTIBYTE (file));
                }
            }
        }
    }
  else
    {
      /* We are loading a source file (*.el).  */
      if (!NILP (Vload_source_file_function))
        {
          Lisp_Object val;

          if (fd >= 0)
            emacs_close (fd);
          val = call4 (Vload_source_file_function, found, file,
                       NILP (noerror) ? Qnil : Qt,
                       NILP (nomessage) ? Qnil : Qt);
          return unbind_to (count, val);
        }
    }

#ifdef WINDOWSNT
  emacs_close (fd);
  GCPRO1 (efound);
  efound = ENCODE_FILE (found);
  stream = fopen ((char *) SDATA (efound), fmode);
  UNGCPRO;
#else  /* not WINDOWSNT */
  stream = fdopen (fd, fmode);
#endif /* not WINDOWSNT */
  if (stream == 0)
    {
      emacs_close (fd);
      error ("Failure to create stdio stream for %s", SDATA (file));
    }

  if (! NILP (Vpurify_flag))
    Vpreloaded_file_list = Fcons (file, Vpreloaded_file_list);

  if (NILP (nomessage))
    {
      if (!safe_p)
        message_with_string ("Loading %s (compiled; note unsafe, not compiled in Emacs)...",
                 file, 1);
      else if (!compiled)
        message_with_string ("Loading %s (source)...", file, 1);
      else if (newer)
        message_with_string ("Loading %s (compiled; note, source file is newer)...",
                 file, 1);
      else /* The typical case; compiled file newer than source file.  */
        message_with_string ("Loading %s...", file, 1);
    }

  GCPRO1 (file);
  lispstream = Fcons (Qnil, Qnil);
  XSETCARFASTINT (lispstream, (EMACS_UINT)stream >> 16);
  XSETCDRFASTINT (lispstream, (EMACS_UINT)stream & 0xffff);
  record_unwind_protect (load_unwind, lispstream);
  record_unwind_protect (load_descriptor_unwind, load_descriptor_list);
  specbind (Qload_file_name, found);
  specbind (Qinhibit_file_name_operation, Qnil);
  load_descriptor_list
    = Fcons (make_number (fileno (stream)), load_descriptor_list);
  load_in_progress++;
  readevalloop (Qget_file_char, stream, file, Feval, 0, Qnil, Qnil);
  unbind_to (count, Qnil);

  /* Run any load-hooks for this file.  */
  temp = Fassoc (file, Vafter_load_alist);
  if (!NILP (temp))
    Fprogn (Fcdr (temp));
  UNGCPRO;

  if (saved_doc_string)
    free (saved_doc_string);
  saved_doc_string = 0;
  saved_doc_string_size = 0;

  if (prev_saved_doc_string)
    xfree (prev_saved_doc_string);
  prev_saved_doc_string = 0;
  prev_saved_doc_string_size = 0;

  if (!noninteractive && NILP (nomessage))
    {
      if (!safe_p)
        message_with_string ("Loading %s (compiled; note unsafe, not compiled in Emacs)...done",
                 file, 1);
      else if (!compiled)
        message_with_string ("Loading %s (source)...done", file, 1);
      else if (newer)
        message_with_string ("Loading %s (compiled; note, source file is newer)...done",
                 file, 1);
      else /* The typical case; compiled file newer than source file.  */
        message_with_string ("Loading %s...done", file, 1);
    }

  return Qt;
}

static Lisp_Object
load_unwind (stream)  /* used as unwind-protect function in load */
     Lisp_Object stream;
{
  fclose ((FILE *) (XFASTINT (XCAR (stream)) << 16
                    | XFASTINT (XCDR (stream))));
  if (--load_in_progress < 0) load_in_progress = 0;
  return Qnil;
}

static Lisp_Object
load_descriptor_unwind (oldlist)
     Lisp_Object oldlist;
{
  load_descriptor_list = oldlist;
  return Qnil;
}

/* Close all descriptors in use for Floads.
   This is used when starting a subprocess.  */

void
close_load_descs ()
{
#ifndef WINDOWSNT
  Lisp_Object tail;
  for (tail = load_descriptor_list; !NILP (tail); tail = XCDR (tail))
    emacs_close (XFASTINT (XCAR (tail)));
#endif
}
\f
static int
complete_filename_p (pathname)
     Lisp_Object pathname;
{
  register const unsigned char *s = SDATA (pathname);
  return (IS_DIRECTORY_SEP (s[0])
          || (SCHARS (pathname) > 2
              && IS_DEVICE_SEP (s[1]) && IS_DIRECTORY_SEP (s[2]))
#ifdef ALTOS
          || *s == '@'
#endif
#ifdef VMS
          || index (s, ':')
#endif /* VMS */
          );
}

DEFUN ("locate-file-internal", Flocate_file_internal, Slocate_file_internal, 2, 4, 0,
       doc: /* Search for FILENAME through PATH.
If SUFFIXES is non-nil, it should be a list of suffixes to append to
file name when searching.
If non-nil, PREDICATE is used instead of `file-readable-p'.
PREDICATE can also be an integer to pass to the access(2) function,
in which case file-name-handlers are ignored.  */)
     (filename, path, suffixes, predicate)
     Lisp_Object filename, path, suffixes, predicate;
{
  Lisp_Object file;
  int fd = openp (path, filename, suffixes, &file, predicate);
  if (NILP (predicate) && fd > 0)
    close (fd);
  return file;
}


/* Search for a file whose name is STR, looking in directories
   in the Lisp list PATH, and trying suffixes from SUFFIX.
   On success, returns a file descriptor.  On failure, returns -1.

   SUFFIXES is a list of strings containing possible suffixes.
   The empty suffix is automatically added iff the list is empty.

   PREDICATE non-nil means don't open the files,
   just look for one that satisfies the predicate.  In this case,
   returns 1 on success.  The predicate can be a lisp function or
   an integer to pass to `access' (in which case file-name-handlers
   are ignored).

   If STOREPTR is nonzero, it points to a slot where the name of
   the file actually found should be stored as a Lisp string.
   nil is stored there on failure.

   If the file we find is remote, return -2
   but store the found remote file name in *STOREPTR.  */

int
openp (path, str, suffixes, storeptr, predicate)
     Lisp_Object path, str;
     Lisp_Object suffixes;
     Lisp_Object *storeptr;
     Lisp_Object predicate;
{
  register int fd;
  int fn_size = 100;
  char buf[100];
  register char *fn = buf;
  int absolute = 0;
  int want_size;
  Lisp_Object filename;
  struct stat st;
  struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5, gcpro6;
  Lisp_Object string, tail, encoded_fn;
  int max_suffix_len = 0;

  for (tail = suffixes; CONSP (tail); tail = XCDR (tail))
    {
      CHECK_STRING_CAR (tail);
      max_suffix_len = max (max_suffix_len,
                            SBYTES (XCAR (tail)));
    }

  string = filename = Qnil;
  GCPRO6 (str, string, filename, path, suffixes, encoded_fn);

  if (storeptr)
    *storeptr = Qnil;

  if (complete_filename_p (str))
    absolute = 1;

  for (; CONSP (path); path = XCDR (path))
    {
      filename = Fexpand_file_name (str, XCAR (path));
      if (!complete_filename_p (filename))
        /* If there are non-absolute elts in PATH (eg ".") */
        /* Of course, this could conceivably lose if luser sets
           default-directory to be something non-absolute... */
        {
          filename = Fexpand_file_name (filename, current_buffer->directory);
          if (!complete_filename_p (filename))
            /* Give up on this path element! */
            continue;
        }

      /* Calculate maximum size of any filename made from
         this path element/specified file name and any possible suffix.  */
      want_size = max_suffix_len + SBYTES (filename) + 1;
      if (fn_size < want_size)
        fn = (char *) alloca (fn_size = 100 + want_size);

      /* Loop over suffixes.  */
      for (tail = NILP (suffixes) ? default_suffixes : suffixes;
           CONSP (tail); tail = XCDR (tail))
        {
          int lsuffix = SBYTES (XCAR (tail));
          Lisp_Object handler;
          int exists;

          /* Concatenate path element/specified name with the suffix.
             If the directory starts with /:, remove that.  */
          if (SCHARS (filename) > 2
              && SREF (filename, 0) == '/'
              && SREF (filename, 1) == ':')
            {
              strncpy (fn, SDATA (filename) + 2,
                       SBYTES (filename) - 2);
              fn[SBYTES (filename) - 2] = 0;
            }
          else
            {
              strncpy (fn, SDATA (filename),
                       SBYTES (filename));
              fn[SBYTES (filename)] = 0;
            }

          if (lsuffix != 0)  /* Bug happens on CCI if lsuffix is 0.  */
            strncat (fn, SDATA (XCAR (tail)), lsuffix);

          /* Check that the file exists and is not a directory.  */
          /* We used to only check for handlers on non-absolute file names:
                if (absolute)
                  handler = Qnil;
                else
                  handler = Ffind_file_name_handler (filename, Qfile_exists_p);
             It's not clear why that was the case and it breaks things like
             (load "/bar.el") where the file is actually "/bar.el.gz".  */
          handler = Ffind_file_name_handler (filename, Qfile_exists_p);
          string = build_string (fn);
          if ((!NILP (handler) || !NILP (predicate)) && !NATNUMP (predicate))
            {
              if (NILP (predicate))
                exists = !NILP (Ffile_readable_p (string));
              else
                exists = !NILP (call1 (predicate, string));
              if (exists && !NILP (Ffile_directory_p (string)))
                exists = 0;

              if (exists)
                {
                  /* We succeeded; return this descriptor and filename.  */
                  if (storeptr)
                    *storeptr = string;
                  UNGCPRO;
                  return -2;
                }
            }
          else
            {
              const char *pfn;

              encoded_fn = ENCODE_FILE (string);
              pfn = SDATA (encoded_fn);
              exists = (stat (pfn, &st) >= 0
                        && (st.st_mode & S_IFMT) != S_IFDIR);
              if (exists)
                {
                  /* Check that we can access or open it.  */
                  if (NATNUMP (predicate))
                    fd = (access (pfn, XFASTINT (predicate)) == 0) ? 1 : -1;
                  else
                    fd = emacs_open (pfn, O_RDONLY, 0);

                  if (fd >= 0)
                    {
                      /* We succeeded; return this descriptor and filename.  */
                      if (storeptr)
                        *storeptr = string;
                      UNGCPRO;
                      return fd;
                    }
                }
            }
        }
      if (absolute)
        break;
    }

  UNGCPRO;
  return -1;
}

\f
/* Merge the list we've accumulated of globals from the current input source
   into the load_history variable.  The details depend on whether
   the source has an associated file name or not. */

static void
build_load_history (stream, source)
     FILE *stream;
     Lisp_Object source;
{
  register Lisp_Object tail, prev, newelt;
  register Lisp_Object tem, tem2;
  register int foundit, loading;

  loading = stream || !NARROWED;

  tail = Vload_history;
  prev = Qnil;
  foundit = 0;
  while (CONSP (tail))
    {
      tem = XCAR (tail);

      /* Find the feature's previous assoc list... */
      if (!NILP (Fequal (source, Fcar (tem))))
        {
          foundit = 1;

          /*  If we're loading, remove it. */
          if (loading)
            {
              if (NILP (prev))
                Vload_history = XCDR (tail);
              else
                Fsetcdr (prev, XCDR (tail));
            }

          /*  Otherwise, cons on new symbols that are not already members.  */
          else
            {
              tem2 = Vcurrent_load_list;

              while (CONSP (tem2))
                {
                  newelt = XCAR (tem2);

                  if (NILP (Fmember (newelt, tem)))
                    Fsetcar (tail, Fcons (XCAR (tem),
                                          Fcons (newelt, XCDR (tem))));

                  tem2 = XCDR (tem2);
                  QUIT;
                }
            }
        }
      else
        prev = tail;
      tail = XCDR (tail);
      QUIT;
    }

  /* If we're loading, cons the new assoc onto the front of load-history,
     the most-recently-loaded position.  Also do this if we didn't find
     an existing member for the current source.  */
  if (loading || !foundit)
    Vload_history = Fcons (Fnreverse (Vcurrent_load_list),
                           Vload_history);
}

Lisp_Object
unreadpure (junk) /* Used as unwind-protect function in readevalloop */
     Lisp_Object junk;
{
  read_pure = 0;
  return Qnil;
}

static Lisp_Object
readevalloop_1 (old)
     Lisp_Object old;
{
  load_convert_to_unibyte = ! NILP (old);
  return Qnil;
}

/* Signal an `end-of-file' error, if possible with file name
   information.  */

static void
end_of_file_error ()
{
  Lisp_Object data;

  if (STRINGP (Vload_file_name))
    data = Fcons (Vload_file_name, Qnil);
  else
    data = Qnil;

  Fsignal (Qend_of_file, data);
}

/* UNIBYTE specifies how to set load_convert_to_unibyte
   for this invocation.
   READFUN, if non-nil, is used instead of `read'.  */

static void
readevalloop (readcharfun, stream, sourcename, evalfun, printflag, unibyte, readfun)
     Lisp_Object readcharfun;
     FILE *stream;
     Lisp_Object sourcename;
     Lisp_Object (*evalfun) ();
     int printflag;
     Lisp_Object unibyte, readfun;
{
  register int c;
  register Lisp_Object val;
  int count = SPECPDL_INDEX ();
  struct gcpro gcpro1;
  struct buffer *b = 0;
  int continue_reading_p;

  if (BUFFERP (readcharfun))
    b = XBUFFER (readcharfun);
  else if (MARKERP (readcharfun))
    b = XMARKER (readcharfun)->buffer;

  specbind (Qstandard_input, readcharfun);
  specbind (Qcurrent_load_list, Qnil);
  record_unwind_protect (readevalloop_1, load_convert_to_unibyte ? Qt : Qnil);
  load_convert_to_unibyte = !NILP (unibyte);

  readchar_backlog = -1;

  GCPRO1 (sourcename);

  LOADHIST_ATTACH (sourcename);

  continue_reading_p = 1;
  while (continue_reading_p)
    {
      if (b != 0 && NILP (b->name))
        error ("Reading from killed buffer");

      instream = stream;
      c = READCHAR;
      if (c == ';')
        {
          while ((c = READCHAR) != '\n' && c != -1);
          continue;
        }
      if (c < 0) break;

      /* Ignore whitespace here, so we can detect eof.  */
      if (c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r')
        continue;

      if (!NILP (Vpurify_flag) && c == '(')
        {
          int count1 = SPECPDL_INDEX ();
          record_unwind_protect (unreadpure, Qnil);
          val = read_list (-1, readcharfun);
          unbind_to (count1, Qnil);
        }
      else
        {
          UNREAD (c);
          read_objects = Qnil;
          if (!NILP (readfun))
            {
              val = call1 (readfun, readcharfun);

              /* If READCHARFUN has set point to ZV, we should
                 stop reading, even if the form read sets point
                 to a different value when evaluated.  */
              if (BUFFERP (readcharfun))
                {
                  struct buffer *b = XBUFFER (readcharfun);
                  if (BUF_PT (b) == BUF_ZV (b))
                    continue_reading_p = 0;
                }
            }
          else if (! NILP (Vload_read_function))
            val = call1 (Vload_read_function, readcharfun);
          else
            val = read_internal_start (readcharfun, Qnil, Qnil);
        }

      val = (*evalfun) (val);

      if (printflag)
        {
          Vvalues = Fcons (val, Vvalues);
          if (EQ (Vstandard_output, Qt))
            Fprin1 (val, Qnil);
          else
            Fprint (val, Qnil);
        }
    }

  build_load_history (stream, sourcename);
  UNGCPRO;

  unbind_to (count, Qnil);
}

DEFUN ("eval-buffer", Feval_buffer, Seval_buffer, 0, 5, "",
       doc: /* Execute the current buffer as Lisp code.
Programs can pass two arguments, BUFFER and PRINTFLAG.
BUFFER is the buffer to evaluate (nil means use current buffer).
PRINTFLAG controls printing of output:
nil means discard it; anything else is stream for print.

If the optional third argument FILENAME is non-nil,
it specifies the file name to use for `load-history'.
The optional fourth argument UNIBYTE specifies `load-convert-to-unibyte'
for this invocation.

The optional fifth argument DO-ALLOW-PRINT, if non-nil, specifies that
`print' and related functions should work normally even if PRINTFLAG is nil.

This function preserves the position of point.  */)
     (buffer, printflag, filename, unibyte, do_allow_print)
     Lisp_Object buffer, printflag, filename, unibyte, do_allow_print;
{
  int count = SPECPDL_INDEX ();
  Lisp_Object tem, buf;

  if (NILP (buffer))
    buf = Fcurrent_buffer ();
  else
    buf = Fget_buffer (buffer);
  if (NILP (buf))
    error ("No such buffer");

  if (NILP (printflag) && NILP (do_allow_print))
    tem = Qsymbolp;
  else
    tem = printflag;

  if (NILP (filename))
    filename = XBUFFER (buf)->filename;

  specbind (Qstandard_output, tem);
  record_unwind_protect (save_excursion_restore, save_excursion_save ());
  BUF_SET_PT (XBUFFER (buf), BUF_BEGV (XBUFFER (buf)));
  readevalloop (buf, 0, filename, Feval, !NILP (printflag), unibyte, Qnil);
  unbind_to (count, Qnil);

  return Qnil;
}

DEFUN ("eval-region", Feval_region, Seval_region, 2, 4, "r",
       doc: /* Execute the region as Lisp code.
When called from programs, expects two arguments,
giving starting and ending indices in the current buffer
of the text to be executed.
Programs can pass third argument PRINTFLAG which controls output:
nil means discard it; anything else is stream for printing it.
Also the fourth argument READ-FUNCTION, if non-nil, is used
instead of `read' to read each expression.  It gets one argument
which is the input stream for reading characters.

This function does not move point.  */)
     (start, end, printflag, read_function)
     Lisp_Object start, end, printflag, read_function;
{
  int count = SPECPDL_INDEX ();
  Lisp_Object tem, cbuf;

  cbuf = Fcurrent_buffer ();

  if (NILP (printflag))
    tem = Qsymbolp;
  else
    tem = printflag;
  specbind (Qstandard_output, tem);

  if (NILP (printflag))
    record_unwind_protect (save_excursion_restore, save_excursion_save ());
  record_unwind_protect (save_restriction_restore, save_restriction_save ());

  /* This both uses start and checks its type.  */
  Fgoto_char (start);
  Fnarrow_to_region (make_number (BEGV), end);
  readevalloop (cbuf, 0, XBUFFER (cbuf)->filename, Feval,
                !NILP (printflag), Qnil, read_function);

  return unbind_to (count, Qnil);
}

\f
DEFUN ("read", Fread, Sread, 0, 1, 0,
       doc: /* Read one Lisp expression as text from STREAM, return as Lisp object.
If STREAM is nil, use the value of `standard-input' (which see).
STREAM or the value of `standard-input' may be:
 a buffer (read from point and advance it)
 a marker (read from where it points and advance it)
 a function (call it with no arguments for each character,
     call it with a char as argument to push a char back)
 a string (takes text from string, starting at the beginning)
 t (read text line using minibuffer and use it, or read from
    standard input in batch mode).  */)
     (stream)
     Lisp_Object stream;
{
  if (NILP (stream))
    stream = Vstandard_input;
  if (EQ (stream, Qt))
    stream = Qread_char;
  if (EQ (stream, Qread_char))
    return Fread_minibuffer (build_string ("Lisp expression: "), Qnil);

  return read_internal_start (stream, Qnil, Qnil);
}

DEFUN ("read-from-string", Fread_from_string, Sread_from_string, 1, 3, 0,
       doc: /* Read one Lisp expression which is represented as text by STRING.
Returns a cons: (OBJECT-READ . FINAL-STRING-INDEX).
START and END optionally delimit a substring of STRING from which to read;
 they default to 0 and (length STRING) respectively.  */)
     (string, start, end)
     Lisp_Object string, start, end;
{
  Lisp_Object ret;
  CHECK_STRING (string);
  /* read_internal_start sets read_from_string_index. */
  ret = read_internal_start (string, start, end);
  return Fcons (ret, make_number (read_from_string_index));
}

/* Function to set up the global context we need in toplevel read
   calls. */
static Lisp_Object
read_internal_start (stream, start, end)
     Lisp_Object stream;
     Lisp_Object start; /* Only used when stream is a string. */
     Lisp_Object end; /* Only used when stream is a string. */
{
  Lisp_Object retval;

  readchar_backlog = -1;
  readchar_count = 0;
  new_backquote_flag = 0;
  read_objects = Qnil;
  if (EQ (Vread_with_symbol_positions, Qt)
      || EQ (Vread_with_symbol_positions, stream))
    Vread_symbol_positions_list = Qnil;

  if (STRINGP (stream))
    {
      int startval, endval;
      if (NILP (end))
        endval = SCHARS (stream);
      else
        {
          CHECK_NUMBER (end);
          endval = XINT (end);
          if (endval < 0 || endval > SCHARS (stream))
            args_out_of_range (stream, end);
        }

      if (NILP (start))
        startval = 0;
      else
        {
          CHECK_NUMBER (start);
          startval = XINT (start);
          if (startval < 0 || startval > endval)
            args_out_of_range (stream, start);
        }
      read_from_string_index = startval;
      read_from_string_index_byte = string_char_to_byte (stream, startval);
      read_from_string_limit = endval;
    }
      
  retval = read0 (stream);
  if (EQ (Vread_with_symbol_positions, Qt)
      || EQ (Vread_with_symbol_positions, stream))
    Vread_symbol_positions_list = Fnreverse (Vread_symbol_positions_list);
  return retval;
}
\f
/* Use this for recursive reads, in contexts where internal tokens
   are not allowed. */

static Lisp_Object
read0 (readcharfun)
     Lisp_Object readcharfun;
{
  register Lisp_Object val;
  int c;

  val = read1 (readcharfun, &c, 0);
  if (c)
    Fsignal (Qinvalid_read_syntax, Fcons (Fmake_string (make_number (1),
                                                        make_number (c)),
                                          Qnil));

  return val;
}
\f
static int read_buffer_size;
static char *read_buffer;

/* Read multibyte form and return it as a character.  C is a first
   byte of multibyte form, and rest of them are read from
   READCHARFUN.  */

static int
read_multibyte (c, readcharfun)
     register int c;
     Lisp_Object readcharfun;
{
  /* We need the actual character code of this multibyte
     characters.  */
  unsigned char str[MAX_MULTIBYTE_LENGTH];
  int len = 0;
  int bytes;

  if (c < 0)
    return c;

  str[len++] = c;
  while ((c = READCHAR) >= 0xA0
         && len < MAX_MULTIBYTE_LENGTH)
    {
      str[len++] = c;
      readchar_count--;
    }
  UNREAD (c);
  if (UNIBYTE_STR_AS_MULTIBYTE_P (str, len, bytes))
    return STRING_CHAR (str, len);
  /* The byte sequence is not valid as multibyte.  Unread all bytes
     but the first one, and return the first byte.  */
  while (--len > 0)
    UNREAD (str[len]);
  return str[0];
}

/* Read a \-escape sequence, assuming we already read the `\'.
   If the escape sequence forces unibyte, store 1 into *BYTEREP.
   If the escape sequence forces multibyte, store 2 into *BYTEREP.
   Otherwise store 0 into *BYTEREP.  */

static int
read_escape (readcharfun, stringp, byterep)
     Lisp_Object readcharfun;
     int stringp;
     int *byterep;
{
  register int c = READCHAR;

  *byterep = 0;

  switch (c)
    {
    case -1:
      end_of_file_error ();

    case 'a':
      return '\007';
    case 'b':
      return '\b';
    case 'd':
      return 0177;
    case 'e':
      return 033;
    case 'f':
      return '\f';
    case 'n':
      return '\n';
    case 'r':
      return '\r';
    case 't':
      return '\t';
    case 'v':
      return '\v';
    case '\n':
      return -1;
    case ' ':
      if (stringp)
        return -1;
      return ' ';

    case 'M':
      c = READCHAR;
      if (c != '-')
        error ("Invalid escape character syntax");
      c = READCHAR;
      if (c == '\\')
        c = read_escape (readcharfun, 0, byterep);
      return c | meta_modifier;

    case 'S':
      c = READCHAR;
      if (c != '-')
        error ("Invalid escape character syntax");
      c = READCHAR;
      if (c == '\\')
        c = read_escape (readcharfun, 0, byterep);
      return c | shift_modifier;

    case 'H':
      c = READCHAR;
      if (c != '-')
        error ("Invalid escape character syntax");
      c = READCHAR;
      if (c == '\\')
        c = read_escape (readcharfun, 0, byterep);
      return c | hyper_modifier;

    case 'A':
      c = READCHAR;
      if (c != '-')
        error ("Invalid escape character syntax");
      c = READCHAR;
      if (c == '\\')
        c = read_escape (readcharfun, 0, byterep);
      return c | alt_modifier;

    case 's':
      c = READCHAR;
      if (c != '-')
        error ("Invalid escape character syntax");
      c = READCHAR;
      if (c == '\\')
        c = read_escape (readcharfun, 0, byterep);
      return c | super_modifier;

    case 'C':
      c = READCHAR;
      if (c != '-')
        error ("Invalid escape character syntax");
    case '^':
      c = READCHAR;
      if (c == '\\')
        c = read_escape (readcharfun, 0, byterep);
      if ((c & ~CHAR_MODIFIER_MASK) == '?')
        return 0177 | (c & CHAR_MODIFIER_MASK);
      else if (! SINGLE_BYTE_CHAR_P ((c & ~CHAR_MODIFIER_MASK)))
        return c | ctrl_modifier;
      /* ASCII control chars are made from letters (both cases),
         as well as the non-letters within 0100...0137.  */
      else if ((c & 0137) >= 0101 && (c & 0137) <= 0132)
        return (c & (037 | ~0177));
      else if ((c & 0177) >= 0100 && (c & 0177) <= 0137)
        return (c & (037 | ~0177));
      else
        return c | ctrl_modifier;

    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
      /* An octal escape, as in ANSI C.  */
      {
        register int i = c - '0';
        register int count = 0;
        while (++count < 3)
          {
            if ((c = READCHAR) >= '0' && c <= '7')
              {
                i *= 8;
                i += c - '0';
              }
            else
              {
                UNREAD (c);
                break;
              }
          }
        
        *byterep = 1;
        return i;
      }

    case 'x':
      /* A hex escape, as in ANSI C.  */
      {
        int i = 0;
        while (1)
          {
            c = READCHAR;
            if (c >= '0' && c <= '9')
              {
                i *= 16;
                i += c - '0';
              }
            else if ((c >= 'a' && c <= 'f')
                     || (c >= 'A' && c <= 'F'))
              {
                i *= 16;
                if (c >= 'a' && c <= 'f')
                  i += c - 'a' + 10;
                else
                  i += c - 'A' + 10;
              }
            else
              {
                UNREAD (c);
                break;
              }
          }

        *byterep = 2;
        return i;
      }

    default:
      if (BASE_LEADING_CODE_P (c))
        c = read_multibyte (c, readcharfun);
      return c;
    }
}


/* Read an integer in radix RADIX using READCHARFUN to read
   characters.  RADIX must be in the interval [2..36]; if it isn't, a
   read error is signaled .  Value is the integer read.  Signals an
   error if encountering invalid read syntax or if RADIX is out of
   range.  */

static Lisp_Object
read_integer (readcharfun, radix)
     Lisp_Object readcharfun;
     int radix;
{
  int ndigits = 0, invalid_p, c, sign = 0;
  EMACS_INT number = 0;

  if (radix < 2 || radix > 36)
    invalid_p = 1;
  else
    {
      number = ndigits = invalid_p = 0;
      sign = 1;

      c = READCHAR;
      if (c == '-')
        {
          c = READCHAR;
          sign = -1;
        }
      else if (c == '+')
        c = READCHAR;
  
      while (c >= 0)
        {
          int digit;
      
          if (c >= '0' && c <= '9')
            digit = c - '0';
          else if (c >= 'a' && c <= 'z')
            digit = c - 'a' + 10;
          else if (c >= 'A' && c <= 'Z')
            digit = c - 'A' + 10;
          else
            {
              UNREAD (c);
              break;
            }

          if (digit < 0 || digit >= radix)
            invalid_p = 1;

          number = radix * number + digit;
          ++ndigits;
          c = READCHAR;
        }
    }

  if (ndigits == 0 || invalid_p)
    {
      char buf[50];
      sprintf (buf, "integer, radix %d", radix);
      Fsignal (Qinvalid_read_syntax, Fcons (build_string (buf), Qnil));
    }

  return make_number (sign * number);
}


/* Convert unibyte text in read_buffer to multibyte.

   Initially, *P is a pointer after the end of the unibyte text, and
   the pointer *END points after the end of read_buffer.

   If read_buffer doesn't have enough room to hold the result
   of the conversion, reallocate it and adjust *P and *END.

   At the end, make *P point after the result of the conversion, and
   return in *NCHARS the number of characters in the converted
   text.  */

static void
to_multibyte (p, end, nchars)
     char **p, **end;
     int *nchars;
{
  int nbytes;

  parse_str_as_multibyte (read_buffer, *p - read_buffer, &nbytes, nchars);
  if (read_buffer_size < 2 * nbytes)
    {
      int offset = *p - read_buffer;
      read_buffer_size = 2 * max (read_buffer_size, nbytes);
      read_buffer = (char *) xrealloc (read_buffer, read_buffer_size);
      *p = read_buffer + offset;
      *end = read_buffer + read_buffer_size;
    }

  if (nbytes != *nchars)
    nbytes = str_as_multibyte (read_buffer, read_buffer_size,
                               *p - read_buffer, nchars);
  
  *p = read_buffer + nbytes;
}


/* If the next token is ')' or ']' or '.', we store that character
   in *PCH and the return value is not interesting.  Else, we store
   zero in *PCH and we read and return one lisp object.

   FIRST_IN_LIST is nonzero if this is the first element of a list.  */

static Lisp_Object
read1 (readcharfun, pch, first_in_list)
     register Lisp_Object readcharfun;
     int *pch;
     int first_in_list;
{
  register int c;
  int uninterned_symbol = 0;

  *pch = 0;

 retry:

  c = READCHAR;
  if (c < 0)
    end_of_file_error ();

  switch (c)
    {
    case '(':
      return read_list (0, readcharfun);

    case '[':
      return read_vector (readcharfun, 0);

    case ')':
    case ']':
      {
        *pch = c;
        return Qnil;
      }

    case '#':
      c = READCHAR;
      if (c == '^')
        {
          c = READCHAR;
          if (c == '[')
            {
              Lisp_Object tmp;
              tmp = read_vector (readcharfun, 0);
              if (XVECTOR (tmp)->size < CHAR_TABLE_STANDARD_SLOTS
                  || XVECTOR (tmp)->size > CHAR_TABLE_STANDARD_SLOTS + 10)
                error ("Invalid size char-table");
              XSETCHAR_TABLE (tmp, XCHAR_TABLE (tmp));
              XCHAR_TABLE (tmp)->top = Qt;
              return tmp;
            }
          else if (c == '^')
            {
              c = READCHAR;
              if (c == '[')
                {
                  Lisp_Object tmp;
                  tmp = read_vector (readcharfun, 0);
                  if (XVECTOR (tmp)->size != SUB_CHAR_TABLE_STANDARD_SLOTS)
                    error ("Invalid size char-table");
                  XSETCHAR_TABLE (tmp, XCHAR_TABLE (tmp));
                  XCHAR_TABLE (tmp)->top = Qnil;
                  return tmp;
                }
              Fsignal (Qinvalid_read_syntax,
                       Fcons (make_string ("#^^", 3), Qnil));
            }
          Fsignal (Qinvalid_read_syntax, Fcons (make_string ("#^", 2), Qnil));
        }
      if (c == '&')
        {
          Lisp_Object length;
          length = read1 (readcharfun, pch, first_in_list);
          c = READCHAR;
          if (c == '"')
            {
              Lisp_Object tmp, val;
              int size_in_chars = ((XFASTINT (length) + BITS_PER_CHAR - 1)
                                   / BITS_PER_CHAR);

              UNREAD (c);
              tmp = read1 (readcharfun, pch, first_in_list);
              if (size_in_chars != SCHARS (tmp)
                  /* We used to print 1 char too many
                     when the number of bits was a multiple of 8.
                     Accept such input in case it came from an old version.  */
                  && ! (XFASTINT (length)
                        == (SCHARS (tmp) - 1) * BITS_PER_CHAR))
                Fsignal (Qinvalid_read_syntax,
                         Fcons (make_string ("#&...", 5), Qnil));
                
              val = Fmake_bool_vector (length, Qnil);
              bcopy (SDATA (tmp), XBOOL_VECTOR (val)->data,
                     size_in_chars);
              /* Clear the extraneous bits in the last byte.  */
              if (XINT (length) != size_in_chars * BITS_PER_CHAR)
                XBOOL_VECTOR (val)->data[size_in_chars - 1]
                  &= (1 << (XINT (length) % BITS_PER_CHAR)) - 1;
              return val;
            }
          Fsignal (Qinvalid_read_syntax, Fcons (make_string ("#&...", 5),
                                                Qnil));
        }
      if (c == '[')
        {
          /* Accept compiled functions at read-time so that we don't have to
             build them using function calls.  */
          Lisp_Object tmp;
          tmp = read_vector (readcharfun, 1);
          return Fmake_byte_code (XVECTOR (tmp)->size,
                                  XVECTOR (tmp)->contents);
        }
      if (c == '(')
        {
          Lisp_Object tmp;
          struct gcpro gcpro1;
          int ch;

          /* Read the string itself.  */
          tmp = read1 (readcharfun, &ch, 0);
          if (ch != 0 || !STRINGP (tmp))
            Fsignal (Qinvalid_read_syntax, Fcons (make_string ("#", 1), Qnil));
          GCPRO1 (tmp);
          /* Read the intervals and their properties.  */
          while (1)
            {
              Lisp_Object beg, end, plist;

              beg = read1 (readcharfun, &ch, 0);
              end = plist = Qnil;
              if (ch == ')')
                break;
              if (ch == 0)
                end = read1 (readcharfun, &ch, 0);
              if (ch == 0)
                plist = read1 (readcharfun, &ch, 0);
              if (ch)
                Fsignal (Qinvalid_read_syntax,
                         Fcons (build_string ("invalid string property list"),
                                Qnil));
              Fset_text_properties (beg, end, plist, tmp);
            }
          UNGCPRO;
          return tmp;
        }
      
      /* #@NUMBER is used to skip NUMBER following characters.
         That's used in .elc files to skip over doc strings
         and function definitions.  */
      if (c == '@')
        {
          int i, nskip = 0;

          /* Read a decimal integer.  */
          while ((c = READCHAR) >= 0
                 && c >= '0' && c <= '9')
            {
              nskip *= 10;
              nskip += c - '0';
            }
          if (c >= 0)
            UNREAD (c);
          
          if (load_force_doc_strings && EQ (readcharfun, Qget_file_char))
            {
              /* If we are supposed to force doc strings into core right now,
                 record the last string that we skipped,
                 and record where in the file it comes from.  */

              /* But first exchange saved_doc_string
                 with prev_saved_doc_string, so we save two strings.  */
              {
                char *temp = saved_doc_string;
                int temp_size = saved_doc_string_size;
                file_offset temp_pos = saved_doc_string_position;
                int temp_len = saved_doc_string_length;

                saved_doc_string = prev_saved_doc_string;
                saved_doc_string_size = prev_saved_doc_string_size;
                saved_doc_string_position = prev_saved_doc_string_position;
                saved_doc_string_length = prev_saved_doc_string_length;

                prev_saved_doc_string = temp;
                prev_saved_doc_string_size = temp_size;
                prev_saved_doc_string_position = temp_pos;
                prev_saved_doc_string_length = temp_len;
              }

              if (saved_doc_string_size == 0)
                {
                  saved_doc_string_size = nskip + 100;
                  saved_doc_string = (char *) xmalloc (saved_doc_string_size);
                }
              if (nskip > saved_doc_string_size)
                {
                  saved_doc_string_size = nskip + 100;
                  saved_doc_string = (char *) xrealloc (saved_doc_string,
                                                        saved_doc_string_size);
                }

              saved_doc_string_position = file_tell (instream);

              /* Copy that many characters into saved_doc_string.  */
              for (i = 0; i < nskip && c >= 0; i++)
                saved_doc_string[i] = c = READCHAR;

              saved_doc_string_length = i;
            }
          else
            {
              /* Skip that many characters.  */
              for (i = 0; i < nskip && c >= 0; i++)
                c = READCHAR;
            }

          goto retry;
        }
      if (c == '!')
        {
          /* #! appears at the beginning of an executable file.
             Skip the first line.  */
          while (c != '\n')
            c = READCHAR;
          goto retry;
        }
      if (c == '$')
        return Vload_file_name;
      if (c == '\'')
        return Fcons (Qfunction, Fcons (read0 (readcharfun), Qnil));
      /* #:foo is the uninterned symbol named foo.  */
      if (c == ':')
        {
          uninterned_symbol = 1;
          c = READCHAR;
          goto default_label;
        }
      /* Reader forms that can reuse previously read objects.  */
      if (c >= '0' && c <= '9')
        {
          int n = 0;
          Lisp_Object tem;

          /* Read a non-negative integer.  */
          while (c >= '0' && c <= '9')
            {
              n *= 10;
              n += c - '0';
              c = READCHAR;
            }
          /* #n=object returns object, but associates it with n for #n#.  */
          if (c == '=')
            {
              /* Make a placeholder for #n# to use temporarily */
              Lisp_Object placeholder;
              Lisp_Object cell;

              placeholder = Fcons(Qnil, Qnil);
              cell = Fcons (make_number (n), placeholder);
              read_objects = Fcons (cell, read_objects);

              /* Read the object itself. */
              tem = read0 (readcharfun);

              /* Now put it everywhere the placeholder was... */
              substitute_object_in_subtree (tem, placeholder);

              /* ...and #n# will use the real value from now on.  */
              Fsetcdr (cell, tem);
              
              return tem;
            }
          /* #n# returns a previously read object.  */
          if (c == '#')
            {
              tem = Fassq (make_number (n), read_objects);
              if (CONSP (tem))
                return XCDR (tem);
              /* Fall through to error message.  */
            }
          else if (c == 'r' ||  c == 'R')
            return read_integer (readcharfun, n);
          
          /* Fall through to error message.  */
        }
      else if (c == 'x' || c == 'X')
        return read_integer (readcharfun, 16);
      else if (c == 'o' || c == 'O')
        return read_integer (readcharfun, 8);
      else if (c == 'b' || c == 'B')
        return read_integer (readcharfun, 2);

      UNREAD (c);
      Fsignal (Qinvalid_read_syntax, Fcons (make_string ("#", 1), Qnil));

    case ';':
      while ((c = READCHAR) >= 0 && c != '\n');
      goto retry;

    case '\'':
      {
        return Fcons (Qquote, Fcons (read0 (readcharfun), Qnil));
      }

    case '`':
      if (first_in_list)
        goto default_label;
      else
        {
          Lisp_Object value;

          new_backquote_flag++;
          value = read0 (readcharfun);
          new_backquote_flag--;

          return Fcons (Qbackquote, Fcons (value, Qnil));
        }

    case ',':
      if (new_backquote_flag)
        {
          Lisp_Object comma_type = Qnil;
          Lisp_Object value;
          int ch = READCHAR;

          if (ch == '@')
            comma_type = Qcomma_at;
          else if (ch == '.')
            comma_type = Qcomma_dot;
          else
            {
              if (ch >= 0) UNREAD (ch);
              comma_type = Qcomma;
            }

          new_backquote_flag--;
          value = read0 (readcharfun);
          new_backquote_flag++;
          return Fcons (comma_type, Fcons (value, Qnil));
        }
      else
        goto default_label;

    case '?':
      {
        int discard;

        c = READCHAR;
        if (c < 0)
          end_of_file_error ();

        if (c == '\\')
          c = read_escape (readcharfun, 0, &discard);
        else if (BASE_LEADING_CODE_P (c))
          c = read_multibyte (c, readcharfun);

        return make_number (c);
      }

    case '"':
      {
        char *p = read_buffer;
        char *end = read_buffer + read_buffer_size;
        register int c;
        /* 1 if we saw an escape sequence specifying
           a multibyte character, or a multibyte character.  */
        int force_multibyte = 0;
        /* 1 if we saw an escape sequence specifying
           a single-byte character.  */
        int force_singlebyte = 0;
        /* 1 if read_buffer contains multibyte text now.  */
        int is_multibyte = 0;
        int cancel = 0;
        int nchars = 0;

        while ((c = READCHAR) >= 0
               && c != '\"')
          {
            if (end - p < MAX_MULTIBYTE_LENGTH)
              {
                int offset = p - read_buffer;
                read_buffer = (char *) xrealloc (read_buffer,
                                                 read_buffer_size *= 2);
                p = read_buffer + offset;
                end = read_buffer + read_buffer_size;
              }

            if (c == '\\')
              {
                int byterep;

                c = read_escape (readcharfun, 1, &byterep);

                /* C is -1 if \ newline has just been seen */
                if (c == -1)
                  {
                    if (p == read_buffer)
                      cancel = 1;
                    continue;
                  }

                if (byterep == 1)
                  force_singlebyte = 1;
                else if (byterep == 2)
                  force_multibyte = 1;
              }

            /* A character that must be multibyte forces multibyte.  */
            if (! SINGLE_BYTE_CHAR_P (c & ~CHAR_MODIFIER_MASK))
              force_multibyte = 1;

            /* If we just discovered the need to be multibyte,
               convert the text accumulated thus far.  */
            if (force_multibyte && ! is_multibyte)
              {
                is_multibyte = 1;
                to_multibyte (&p, &end, &nchars);
              }

            /* Allow `\C- ' and `\C-?'.  */
            if (c == (CHAR_CTL | ' '))
              c = 0;
            else if (c == (CHAR_CTL | '?'))
              c = 127;

            if (c & CHAR_SHIFT)
              {
                /* Shift modifier is valid only with [A-Za-z].  */
                if ((c & 0377) >= 'A' && (c & 0377) <= 'Z')
                  c &= ~CHAR_SHIFT;
                else if ((c & 0377) >= 'a' && (c & 0377) <= 'z')
                  c = (c & ~CHAR_SHIFT) - ('a' - 'A');
              }

            if (c & CHAR_META)
              /* Move the meta bit to the right place for a string.  */
              c = (c & ~CHAR_META) | 0x80;
            if (c & CHAR_MODIFIER_MASK)
              error ("Invalid modifier in string");

            if (is_multibyte)
              p += CHAR_STRING (c, p);
            else
              *p++ = c;

            nchars++;
          }

        if (c < 0)
          end_of_file_error ();

        /* If purifying, and string starts with \ newline,
           return zero instead.  This is for doc strings
           that we are really going to find in etc/DOC.nn.nn  */
        if (!NILP (Vpurify_flag) && NILP (Vdoc_file_name) && cancel)
          return make_number (0);

        if (is_multibyte || force_singlebyte)
          ;
        else if (load_convert_to_unibyte)
          {
            Lisp_Object string;
            to_multibyte (&p, &end, &nchars);
            if (p - read_buffer != nchars)
              {
                string = make_multibyte_string (read_buffer, nchars,
                                                p - read_buffer);
                return Fstring_make_unibyte (string);
              }
            /* We can make a unibyte string directly.  */
            is_multibyte = 0;
          }
        else if (EQ (readcharfun, Qget_file_char)
                 || EQ (readcharfun, Qlambda))
          {
            /* Nowadays, reading directly from a file is used only for
               compiled Emacs Lisp files, and those always use the
               Emacs internal encoding.  Meanwhile, Qlambda is used
               for reading dynamic byte code (compiled with
               byte-compile-dynamic = t).  So make the string multibyte
               if the string contains any multibyte sequences.
               (to_multibyte is a no-op if not.)  */
            to_multibyte (&p, &end, &nchars);
            is_multibyte = (p - read_buffer) != nchars;
          }
        else
          /* In all other cases, if we read these bytes as
             separate characters, treat them as separate characters now.  */
          ;

        /* We want readchar_count to be the number of characters, not
           bytes.  Hence we adjust for multibyte characters in the
           string.  ... But it doesn't seem to be necessary, because
           READCHAR *does* read multibyte characters from buffers. */
        /* readchar_count -= (p - read_buffer) - nchars; */
        if (read_pure)
          return make_pure_string (read_buffer, nchars, p - read_buffer,
                                   is_multibyte);
        return make_specified_string (read_buffer, nchars, p - read_buffer,
                                      is_multibyte);
      }

    case '.':
      {
        int next_char = READCHAR;
        UNREAD (next_char);

        if (next_char <= 040
            || index ("\"'`,(", next_char))
          {
            *pch = c;
            return Qnil;
          }

        /* Otherwise, we fall through!  Note that the atom-reading loop
           below will now loop at least once, assuring that we will not
           try to UNREAD two characters in a row.  */
      }
    default:
    default_label:
      if (c <= 040) goto retry;
      {
        char *p = read_buffer;
        int quoted = 0;

        {
          char *end = read_buffer + read_buffer_size;

          while (c > 040
                 && !(c == '\"' || c == '\'' || c == ';'
                      || c == '(' || c == ')'
                      || c == '[' || c == ']' || c == '#'))
            {
              if (end - p < MAX_MULTIBYTE_LENGTH)
                {
                  int offset = p - read_buffer;
                  read_buffer = (char *) xrealloc (read_buffer,
                                                   read_buffer_size *= 2);
                  p = read_buffer + offset;
                  end = read_buffer + read_buffer_size;
                }
              
              if (c == '\\')
                {
                  c = READCHAR;
                  if (c == -1)
                    end_of_file_error ();
                  quoted = 1;
                }

              if (! SINGLE_BYTE_CHAR_P (c))
                p += CHAR_STRING (c, p);
              else
                *p++ = c;

              c = READCHAR;
            }

          if (p == end)
            {
              int offset = p - read_buffer;
              read_buffer = (char *) xrealloc (read_buffer,
                                               read_buffer_size *= 2);
              p = read_buffer + offset;
              end = read_buffer + read_buffer_size;
            }
          *p = 0;
          if (c >= 0)
            UNREAD (c);
        }

        if (!quoted && !uninterned_symbol)
          {
            register char *p1;
            register Lisp_Object val;
            p1 = read_buffer;
            if (*p1 == '+' || *p1 == '-') p1++;
            /* Is it an integer? */
            if (p1 != p)
              {
                while (p1 != p && (c = *p1) >= '0' && c <= '9') p1++;
                /* Integers can have trailing decimal points.  */
                if (p1 > read_buffer && p1 < p && *p1 == '.') p1++;
                if (p1 == p)
                  /* It is an integer. */
                  {
                    if (p1[-1] == '.')
                      p1[-1] = '\0';
                    if (sizeof (int) == sizeof (EMACS_INT))
                      XSETINT (val, atoi (read_buffer));
                    else if (sizeof (long) == sizeof (EMACS_INT))
                      XSETINT (val, atol (read_buffer));
                    else
                      abort ();
                    return val;
                  }
              }
            if (isfloat_string (read_buffer))
              {
                /* Compute NaN and infinities using 0.0 in a variable,
                   to cope with compilers that think they are smarter
                   than we are.  */
                double zero = 0.0;

                double value;

                /* Negate the value ourselves.  This treats 0, NaNs,
                   and infinity properly on IEEE floating point hosts,
                   and works around a common bug where atof ("-0.0")
                   drops the sign.  */
                int negative = read_buffer[0] == '-';

                /* The only way p[-1] can be 'F' or 'N', after isfloat_string
                   returns 1, is if the input ends in e+INF or e+NaN.  */
                switch (p[-1])
                  {
                  case 'F':
                    value = 1.0 / zero;
                    break;
                  case 'N':
                    value = zero / zero;
                    break;
                  default:
                    value = atof (read_buffer + negative);
                    break;
                  }

                return make_float (negative ? - value : value);
              }
          }
        {
          Lisp_Object result = uninterned_symbol ? make_symbol (read_buffer)
            : intern (read_buffer);
          if (EQ (Vread_with_symbol_positions, Qt)
              || EQ (Vread_with_symbol_positions, readcharfun))
            Vread_symbol_positions_list = 
              /* Kind of a hack; this will probably fail if characters
                 in the symbol name were escaped.  Not really a big
                 deal, though.  */
              Fcons (Fcons (result,
                            make_number (readchar_count
                                         - XFASTINT (Flength (Fsymbol_name (result))))),
                     Vread_symbol_positions_list);
          return result;
        }
      }
    }
}
\f

/* List of nodes we've seen during substitute_object_in_subtree. */
static Lisp_Object seen_list;

static void
substitute_object_in_subtree (object, placeholder)
     Lisp_Object object;
     Lisp_Object placeholder;
{
  Lisp_Object check_object;

  /* We haven't seen any objects when we start. */
  seen_list = Qnil;

  /* Make all the substitutions. */
  check_object
    = substitute_object_recurse (object, placeholder, object);
  
  /* Clear seen_list because we're done with it. */
  seen_list = Qnil;

  /* The returned object here is expected to always eq the
     original. */
  if (!EQ (check_object, object))
    error ("Unexpected mutation error in reader");
}

/*  Feval doesn't get called from here, so no gc protection is needed. */
#define SUBSTITUTE(get_val, set_val)                 \
{                                                    \
  Lisp_Object old_value = get_val;                   \
  Lisp_Object true_value                             \
    = substitute_object_recurse (object, placeholder,\
                               old_value);           \
                                                     \
  if (!EQ (old_value, true_value))                   \
    {                                                \
       set_val;                                      \
    }                                                \
}

static Lisp_Object
substitute_object_recurse (object, placeholder, subtree)
     Lisp_Object object;
     Lisp_Object placeholder;
     Lisp_Object subtree;
{
  /* If we find the placeholder, return the target object. */
  if (EQ (placeholder, subtree))
    return object;

  /* If we've been to this node before, don't explore it again. */
  if (!EQ (Qnil, Fmemq (subtree, seen_list)))
    return subtree;

  /* If this node can be the entry point to a cycle, remember that
     we've seen it.  It can only be such an entry point if it was made
     by #n=, which means that we can find it as a value in
     read_objects.  */
  if (!EQ (Qnil, Frassq (subtree, read_objects)))
    seen_list = Fcons (subtree, seen_list);
      
  /* Recurse according to subtree's type.
     Every branch must return a Lisp_Object.  */
  switch (XTYPE (subtree))
    {
    case Lisp_Vectorlike:
      {
        int i;
        int length = XINT (Flength(subtree));
        for (i = 0; i < length; i++)
          {
            Lisp_Object idx = make_number (i);
            SUBSTITUTE (Faref (subtree, idx),
                        Faset (subtree, idx, true_value)); 
          }
        return subtree;
      }

    case Lisp_Cons:
      {
        SUBSTITUTE (Fcar_safe (subtree),
                    Fsetcar (subtree, true_value));
        SUBSTITUTE (Fcdr_safe (subtree),
                    Fsetcdr (subtree, true_value));
        return subtree;
      }

    case Lisp_String:
      {
        /* Check for text properties in each interval.
           substitute_in_interval contains part of the logic. */

        INTERVAL    root_interval = STRING_INTERVALS (subtree);
        Lisp_Object arg           = Fcons (object, placeholder);
           
        traverse_intervals_noorder (root_interval,
                                    &substitute_in_interval, arg);

        return subtree;
      }

      /* Other types don't recurse any further. */
    default:
      return subtree;
    }
}

/*  Helper function for substitute_object_recurse.  */
static void
substitute_in_interval (interval, arg)
     INTERVAL    interval;
     Lisp_Object arg;
{
  Lisp_Object object      = Fcar (arg);
  Lisp_Object placeholder = Fcdr (arg);

  SUBSTITUTE(interval->plist, interval->plist = true_value);
}

\f
#define LEAD_INT 1
#define DOT_CHAR 2
#define TRAIL_INT 4
#define E_CHAR 8
#define EXP_INT 16

int
isfloat_string (cp)
     register char *cp;
{
  register int state;
  
  char *start = cp;

  state = 0;
  if (*cp == '+' || *cp == '-')
    cp++;

  if (*cp >= '0' && *cp <= '9')
    {
      state |= LEAD_INT;
      while (*cp >= '0' && *cp <= '9')
        cp++;
    }
  if (*cp == '.')
    {
      state |= DOT_CHAR;
      cp++;
    }
  if (*cp >= '0' && *cp <= '9')
    {
      state |= TRAIL_INT;
      while (*cp >= '0' && *cp <= '9')
        cp++;
    }
  if (*cp == 'e' || *cp == 'E')
    {
      state |= E_CHAR;
      cp++;
      if (*cp == '+' || *cp == '-')
        cp++;
    }

  if (*cp >= '0' && *cp <= '9')
    {
      state |= EXP_INT;
      while (*cp >= '0' && *cp <= '9')
        cp++;
    }
  else if (cp == start)
    ;
  else if (cp[-1] == '+' && cp[0] == 'I' && cp[1] == 'N' && cp[2] == 'F')
    {
      state |= EXP_INT;
      cp += 3;
    }
  else if (cp[-1] == '+' && cp[0] == 'N' && cp[1] == 'a' && cp[2] == 'N')
    {
      state |= EXP_INT;
      cp += 3;
    }

  return (((*cp == 0) || (*cp == ' ') || (*cp == '\t') || (*cp == '\n') || (*cp == '\r') || (*cp == '\f'))
          && (state == (LEAD_INT|DOT_CHAR|TRAIL_INT)
              || state == (DOT_CHAR|TRAIL_INT)
              || state == (LEAD_INT|E_CHAR|EXP_INT)
              || state == (LEAD_INT|DOT_CHAR|TRAIL_INT|E_CHAR|EXP_INT)
              || state == (DOT_CHAR|TRAIL_INT|E_CHAR|EXP_INT)));
}

\f
static Lisp_Object
read_vector (readcharfun, bytecodeflag)
     Lisp_Object readcharfun;
     int bytecodeflag;
{
  register int i;
  register int size;
  register Lisp_Object *ptr;
  register Lisp_Object tem, item, vector;
  register struct Lisp_Cons *otem;
  Lisp_Object len;

  tem = read_list (1, readcharfun);
  len = Flength (tem);
  vector = (read_pure ? make_pure_vector (XINT (len)) : Fmake_vector (len, Qnil));

  size = XVECTOR (vector)->size;
  ptr = XVECTOR (vector)->contents;
  for (i = 0; i < size; i++)
    {
      item = Fcar (tem);
      /* If `load-force-doc-strings' is t when reading a lazily-loaded
         bytecode object, the docstring containing the bytecode and
         constants values must be treated as unibyte and passed to
         Fread, to get the actual bytecode string and constants vector.  */
      if (bytecodeflag && load_force_doc_strings)
        {
          if (i == COMPILED_BYTECODE)
            {
              if (!STRINGP (item))
                error ("invalid byte code");

              /* Delay handling the bytecode slot until we know whether
                 it is lazily-loaded (we can tell by whether the
                 constants slot is nil).  */
              ptr[COMPILED_CONSTANTS] = item;
              item = Qnil;
            }
          else if (i == COMPILED_CONSTANTS)
            {
              Lisp_Object bytestr = ptr[COMPILED_CONSTANTS];

              if (NILP (item))
                {
                  /* Coerce string to unibyte (like string-as-unibyte,
                     but without generating extra garbage and
                     guaranteeing no change in the contents).  */
                  STRING_SET_CHARS (bytestr, SBYTES (bytestr));
                  STRING_SET_UNIBYTE (bytestr);

                  item = Fread (bytestr);
                  if (!CONSP (item))
                    error ("invalid byte code");

                  otem = XCONS (item);
                  bytestr = XCAR (item);
                  item = XCDR (item);
                  free_cons (otem);
                }

              /* Now handle the bytecode slot.  */
              ptr[COMPILED_BYTECODE] = read_pure ? Fpurecopy (bytestr) : bytestr;
            }
        }
      ptr[i] = read_pure ? Fpurecopy (item) : item;
      otem = XCONS (tem);
      tem = Fcdr (tem);
      free_cons (otem);
    }
  return vector;
}
  
/* FLAG = 1 means check for ] to terminate rather than ) and .
   FLAG = -1 means check for starting with defun
    and make structure pure.  */

static Lisp_Object
read_list (flag, readcharfun)
     int flag;
     register Lisp_Object readcharfun;
{
  /* -1 means check next element for defun,
     0 means don't check,
     1 means already checked and found defun. */
  int defunflag = flag < 0 ? -1 : 0;
  Lisp_Object val, tail;
  register Lisp_Object elt, tem;
  struct gcpro gcpro1, gcpro2;
  /* 0 is the normal case.
     1 means this list is a doc reference; replace it with the number 0.
     2 means this list is a doc reference; replace it with the doc string.  */ 
  int doc_reference = 0;

  /* Initialize this to 1 if we are reading a list.  */
  int first_in_list = flag <= 0;

  val = Qnil;
  tail = Qnil;

  while (1)
    {
      int ch;
      GCPRO2 (val, tail);
      elt = read1 (readcharfun, &ch, first_in_list);
      UNGCPRO;

      first_in_list = 0;

      /* While building, if the list starts with #$, treat it specially.  */
      if (EQ (elt, Vload_file_name)
          && ! NILP (elt)
          && !NILP (Vpurify_flag))
        {
          if (NILP (Vdoc_file_name))
            /* We have not yet called Snarf-documentation, so assume
               this file is described in the DOC-MM.NN file
               and Snarf-documentation will fill in the right value later.
               For now, replace the whole list with 0.  */
            doc_reference = 1;
          else
            /* We have already called Snarf-documentation, so make a relative
               file name for this file, so it can be found properly
               in the installed Lisp directory.
               We don't use Fexpand_file_name because that would make
               the directory absolute now.  */
            elt = concat2 (build_string ("../lisp/"),
                           Ffile_name_nondirectory (elt));
        }
      else if (EQ (elt, Vload_file_name)
               && ! NILP (elt)
               && load_force_doc_strings)
        doc_reference = 2;

      if (ch)
        {
          if (flag > 0)
            {
              if (ch == ']')
                return val;
              Fsignal (Qinvalid_read_syntax,
                       Fcons (make_string (") or . in a vector", 18), Qnil));
            }
          if (ch == ')')
            return val;
          if (ch == '.')
            {
              GCPRO2 (val, tail);
              if (!NILP (tail))
                XSETCDR (tail, read0 (readcharfun));
              else
                val = read0 (readcharfun);
              read1 (readcharfun, &ch, 0);
              UNGCPRO;
              if (ch == ')')
                {
                  if (doc_reference == 1)
                    return make_number (0);
                  if (doc_reference == 2)
                    {
                      /* Get a doc string from the file we are loading.
                         If it's in saved_doc_string, get it from there.  */
                      int pos = XINT (XCDR (val));
                      /* Position is negative for user variables.  */
                      if (pos < 0) pos = -pos;
                      if (pos >= saved_doc_string_position
                          && pos < (saved_doc_string_position
                                    + saved_doc_string_length))
                        {
                          int start = pos - saved_doc_string_position;
                          int from, to;

                          /* Process quoting with ^A,
                             and find the end of the string,
                             which is marked with ^_ (037).  */
                          for (from = start, to = start;
                               saved_doc_string[from] != 037;)
                            {
                              int c = saved_doc_string[from++];
                              if (c == 1)
                                {
                                  c = saved_doc_string[from++];
                                  if (c == 1)
                                    saved_doc_string[to++] = c;
                                  else if (c == '0')
                                    saved_doc_string[to++] = 0;
                                  else if (c == '_')
                                    saved_doc_string[to++] = 037;
                                }
                              else
                                saved_doc_string[to++] = c;
                            }

                          return make_string (saved_doc_string + start,
                                              to - start);
                        }
                      /* Look in prev_saved_doc_string the same way.  */
                      else if (pos >= prev_saved_doc_string_position
                               && pos < (prev_saved_doc_string_position
                                         + prev_saved_doc_string_length))
                        {
                          int start = pos - prev_saved_doc_string_position;
                          int from, to;

                          /* Process quoting with ^A,
                             and find the end of the string,
                             which is marked with ^_ (037).  */
                          for (from = start, to = start;
                               prev_saved_doc_string[from] != 037;)
                            {
                              int c = prev_saved_doc_string[from++];
                              if (c == 1)
                                {
                                  c = prev_saved_doc_string[from++];
                                  if (c == 1)
                                    prev_saved_doc_string[to++] = c;
                                  else if (c == '0')
                                    prev_saved_doc_string[to++] = 0;
                                  else if (c == '_')
                                    prev_saved_doc_string[to++] = 037;
                                }
                              else
                                prev_saved_doc_string[to++] = c;
                            }

                          return make_string (prev_saved_doc_string + start,
                                              to - start);
                        }
                      else
                        return get_doc_string (val, 0, 0);
                    }

                  return val;
                }
              return Fsignal (Qinvalid_read_syntax, Fcons (make_string (". in wrong context", 18), Qnil));
            }
          return Fsignal (Qinvalid_read_syntax, Fcons (make_string ("] in a list", 11), Qnil));
        }
      tem = (read_pure && flag <= 0
             ? pure_cons (elt, Qnil)
             : Fcons (elt, Qnil));
      if (!NILP (tail))
        XSETCDR (tail, tem);
      else
        val = tem;
      tail = tem;
      if (defunflag < 0)
        defunflag = EQ (elt, Qdefun);
      else if (defunflag > 0)
        read_pure = 1;
    }
}
\f
Lisp_Object Vobarray;
Lisp_Object initial_obarray;

/* oblookup stores the bucket number here, for the sake of Funintern.  */

int oblookup_last_bucket_number;

static int hash_string ();

/* Get an error if OBARRAY is not an obarray.
   If it is one, return it.  */

Lisp_Object
check_obarray (obarray)
     Lisp_Object obarray;
{
  while (!VECTORP (obarray) || XVECTOR (obarray)->size == 0)
    {
      /* If Vobarray is now invalid, force it to be valid.  */
      if (EQ (Vobarray, obarray)) Vobarray = initial_obarray;

      obarray = wrong_type_argument (Qvectorp, obarray);
    }
  return obarray;
}

/* Intern the C string STR: return a symbol with that name,
   interned in the current obarray.  */

Lisp_Object
intern (str)
     const char *str;
{
  Lisp_Object tem;
  int len = strlen (str);
  Lisp_Object obarray;

  obarray = Vobarray;
  if (!VECTORP (obarray) || XVECTOR (obarray)->size == 0)
    obarray = check_obarray (obarray);
  tem = oblookup (obarray, str, len, len);
  if (SYMBOLP (tem))
    return tem;
  return Fintern (make_string (str, len), obarray);
}

/* Create an uninterned symbol with name STR.  */

Lisp_Object
make_symbol (str)
     char *str;
{
  int len = strlen (str);

  return Fmake_symbol ((!NILP (Vpurify_flag)
                        ? make_pure_string (str, len, len, 0)
                        : make_string (str, len)));
}
\f
DEFUN ("intern", Fintern, Sintern, 1, 2, 0,
       doc: /* Return the canonical symbol whose name is STRING.
If there is none, one is created by this function and returned.
A second optional argument specifies the obarray to use;
it defaults to the value of `obarray'.  */)
     (string, obarray)
     Lisp_Object string, obarray;
{
  register Lisp_Object tem, sym, *ptr;

  if (NILP (obarray)) obarray = Vobarray;
  obarray = check_obarray (obarray);

  CHECK_STRING (string);

  tem = oblookup (obarray, SDATA (string),
                  SCHARS (string),
                  SBYTES (string));
  if (!INTEGERP (tem))
    return tem;

  if (!NILP (Vpurify_flag))
    string = Fpurecopy (string);
  sym = Fmake_symbol (string);

  if (EQ (obarray, initial_obarray))
    XSYMBOL (sym)->interned = SYMBOL_INTERNED_IN_INITIAL_OBARRAY;
  else
    XSYMBOL (sym)->interned = SYMBOL_INTERNED;

  if ((SREF (string, 0) == ':')
      && EQ (obarray, initial_obarray))
    {
      XSYMBOL (sym)->constant = 1;
      XSYMBOL (sym)->value = sym;
    }

  ptr = &XVECTOR (obarray)->contents[XINT (tem)];
  if (SYMBOLP (*ptr))
    XSYMBOL (sym)->next = XSYMBOL (*ptr);
  else
    XSYMBOL (sym)->next = 0;
  *ptr = sym;
  return sym;
}

DEFUN ("intern-soft", Fintern_soft, Sintern_soft, 1, 2, 0,
       doc: /* Return the canonical symbol named NAME, or nil if none exists.
NAME may be a string or a symbol.  If it is a symbol, that exact
symbol is searched for.
A second optional argument specifies the obarray to use;
it defaults to the value of `obarray'.  */)
     (name, obarray)
     Lisp_Object name, obarray;
{
  register Lisp_Object tem, string;

  if (NILP (obarray)) obarray = Vobarray;
  obarray = check_obarray (obarray);

  if (!SYMBOLP (name))
    {
      CHECK_STRING (name);
      string = name;
    }
  else
    string = SYMBOL_NAME (name);

  tem = oblookup (obarray, SDATA (string), SCHARS (string), SBYTES (string));
  if (INTEGERP (tem) || (SYMBOLP (name) && !EQ (name, tem)))
    return Qnil;
  else
    return tem;
}
\f
DEFUN ("unintern", Funintern, Sunintern, 1, 2, 0,
       doc: /* Delete the symbol named NAME, if any, from OBARRAY.
The value is t if a symbol was found and deleted, nil otherwise.
NAME may be a string or a symbol.  If it is a symbol, that symbol
is deleted, if it belongs to OBARRAY--no other symbol is deleted.
OBARRAY defaults to the value of the variable `obarray'.  */)
     (name, obarray)
     Lisp_Object name, obarray;
{
  register Lisp_Object string, tem;
  int hash;

  if (NILP (obarray)) obarray = Vobarray;
  obarray = check_obarray (obarray);

  if (SYMBOLP (name))
    string = SYMBOL_NAME (name);
  else
    {
      CHECK_STRING (name);
      string = name;
    }

  tem = oblookup (obarray, SDATA (string),
                  SCHARS (string),
                  SBYTES (string));
  if (INTEGERP (tem))
    return Qnil;
  /* If arg was a symbol, don't delete anything but that symbol itself.  */
  if (SYMBOLP (name) && !EQ (name, tem))
    return Qnil;

  XSYMBOL (tem)->interned = SYMBOL_UNINTERNED;
  XSYMBOL (tem)->constant = 0;
  XSYMBOL (tem)->indirect_variable = 0;

  hash = oblookup_last_bucket_number;

  if (EQ (XVECTOR (obarray)->contents[hash], tem))
    {
      if (XSYMBOL (tem)->next)
        XSETSYMBOL (XVECTOR (obarray)->contents[hash], XSYMBOL (tem)->next);
      else
        XSETINT (XVECTOR (obarray)->contents[hash], 0);
    }
  else
    {
      Lisp_Object tail, following;

      for (tail = XVECTOR (obarray)->contents[hash];
           XSYMBOL (tail)->next;
           tail = following)
        {
          XSETSYMBOL (following, XSYMBOL (tail)->next);
          if (EQ (following, tem))
            {
              XSYMBOL (tail)->next = XSYMBOL (following)->next;
              break;
            }
        }
    }

  return Qt;
}
\f
/* Return the symbol in OBARRAY whose names matches the string
   of SIZE characters (SIZE_BYTE bytes) at PTR.
   If there is no such symbol in OBARRAY, return nil.

   Also store the bucket number in oblookup_last_bucket_number.  */

Lisp_Object
oblookup (obarray, ptr, size, size_byte)
     Lisp_Object obarray;
     register const char *ptr;
     int size, size_byte;
{
  int hash;
  int obsize;
  register Lisp_Object tail;
  Lisp_Object bucket, tem;

  if (!VECTORP (obarray)
      || (obsize = XVECTOR (obarray)->size) == 0)
    {
      obarray = check_obarray (obarray);
      obsize = XVECTOR (obarray)->size;
    }
  /* This is sometimes needed in the middle of GC.  */
  obsize &= ~ARRAY_MARK_FLAG;
  /* Combining next two lines breaks VMS C 2.3.  */
  hash = hash_string (ptr, size_byte);
  hash %= obsize;
  bucket = XVECTOR (obarray)->contents[hash];
  oblookup_last_bucket_number = hash;
  if (XFASTINT (bucket) == 0)
    ;
  else if (!SYMBOLP (bucket))
    error ("Bad data in guts of obarray"); /* Like CADR error message */
  else
    for (tail = bucket; ; XSETSYMBOL (tail, XSYMBOL (tail)->next))
      {
        if (SBYTES (SYMBOL_NAME (tail)) == size_byte
            && SCHARS (SYMBOL_NAME (tail)) == size
            && !bcmp (SDATA (SYMBOL_NAME (tail)), ptr, size_byte))
          return tail;
        else if (XSYMBOL (tail)->next == 0)
          break;
      }
  XSETINT (tem, hash);
  return tem;
}

static int
hash_string (ptr, len)
     const unsigned char *ptr;
     int len;
{
  register const unsigned char *p = ptr;
  register const unsigned char *end = p + len;
  register unsigned char c;
  register int hash = 0;

  while (p != end)
    {
      c = *p++;
      if (c >= 0140) c -= 40;
      hash = ((hash<<3) + (hash>>28) + c);
    }
  return hash & 07777777777;
}
\f
void
map_obarray (obarray, fn, arg)
     Lisp_Object obarray;
     void (*fn) P_ ((Lisp_Object, Lisp_Object));
     Lisp_Object arg;
{
  register int i;
  register Lisp_Object tail;
  CHECK_VECTOR (obarray);
  for (i = XVECTOR (obarray)->size - 1; i >= 0; i--)
    {
      tail = XVECTOR (obarray)->contents[i];
      if (SYMBOLP (tail))
        while (1)
          {
            (*fn) (tail, arg);
            if (XSYMBOL (tail)->next == 0)
              break;
            XSETSYMBOL (tail, XSYMBOL (tail)->next);
          }
    }
}

void
mapatoms_1 (sym, function)
     Lisp_Object sym, function;
{
  call1 (function, sym);
}

DEFUN ("mapatoms", Fmapatoms, Smapatoms, 1, 2, 0,
       doc: /* Call FUNCTION on every symbol in OBARRAY.
OBARRAY defaults to the value of `obarray'.  */)
     (function, obarray)
     Lisp_Object function, obarray;
{
  if (NILP (obarray)) obarray = Vobarray;
  obarray = check_obarray (obarray);

  map_obarray (obarray, mapatoms_1, function);
  return Qnil;
}

#define OBARRAY_SIZE 1511

void
init_obarray ()
{
  Lisp_Object oblength;
  int hash;
  Lisp_Object *tem;

  XSETFASTINT (oblength, OBARRAY_SIZE);

  Qnil = Fmake_symbol (make_pure_string ("nil", 3, 3, 0));
  Vobarray = Fmake_vector (oblength, make_number (0));
  initial_obarray = Vobarray;
  staticpro (&initial_obarray);
  /* Intern nil in the obarray */
  XSYMBOL (Qnil)->interned = SYMBOL_INTERNED_IN_INITIAL_OBARRAY;
  XSYMBOL (Qnil)->constant = 1;
  
  /* These locals are to kludge around a pyramid compiler bug. */
  hash = hash_string ("nil", 3);
  /* Separate statement here to avoid VAXC bug. */
  hash %= OBARRAY_SIZE;
  tem = &XVECTOR (Vobarray)->contents[hash];
  *tem = Qnil;

  Qunbound = Fmake_symbol (make_pure_string ("unbound", 7, 7, 0));
  XSYMBOL (Qnil)->function = Qunbound;
  XSYMBOL (Qunbound)->value = Qunbound;
  XSYMBOL (Qunbound)->function = Qunbound;

  Qt = intern ("t");
  XSYMBOL (Qnil)->value = Qnil;
  XSYMBOL (Qnil)->plist = Qnil;
  XSYMBOL (Qt)->value = Qt;
  XSYMBOL (Qt)->constant = 1;

  /* Qt is correct even if CANNOT_DUMP.  loadup.el will set to nil at end.  */
  Vpurify_flag = Qt;

  Qvariable_documentation = intern ("variable-documentation");
  staticpro (&Qvariable_documentation);

  read_buffer_size = 100 + MAX_MULTIBYTE_LENGTH;
  read_buffer = (char *) xmalloc (read_buffer_size);
}
\f
void
defsubr (sname)
     struct Lisp_Subr *sname;
{
  Lisp_Object sym;
  sym = intern (sname->symbol_name);
  XSETSUBR (XSYMBOL (sym)->function, sname);
}

#ifdef NOTDEF /* use fset in subr.el now */
void
defalias (sname, string)
     struct Lisp_Subr *sname;
     char *string;
{
  Lisp_Object sym;
  sym = intern (string);
  XSETSUBR (XSYMBOL (sym)->function, sname);
}
#endif /* NOTDEF */

/* Define an "integer variable"; a symbol whose value is forwarded
   to a C variable of type int.  Sample call: */
 /* DEFVAR_INT ("indent-tabs-mode", &indent_tabs_mode, "Documentation");  */
void
defvar_int (namestring, address)
     char *namestring;
     EMACS_INT *address;
{
  Lisp_Object sym, val;
  sym = intern (namestring);
  val = allocate_misc ();
  XMISCTYPE (val) = Lisp_Misc_Intfwd;
  XINTFWD (val)->intvar = address;
  SET_SYMBOL_VALUE (sym, val);
}

/* Similar but define a variable whose value is t if address contains 1,
   nil if address contains 0 */
void
defvar_bool (namestring, address)
     char *namestring;
     int *address;
{
  Lisp_Object sym, val;
  sym = intern (namestring);
  val = allocate_misc ();
  XMISCTYPE (val) = Lisp_Misc_Boolfwd;
  XBOOLFWD (val)->boolvar = address;
  SET_SYMBOL_VALUE (sym, val);
  Vbyte_boolean_vars = Fcons (sym, Vbyte_boolean_vars);
}

/* Similar but define a variable whose value is the Lisp Object stored
   at address.  Two versions: with and without gc-marking of the C
   variable.  The nopro version is used when that variable will be
   gc-marked for some other reason, since marking the same slot twice
   can cause trouble with strings.  */
void
defvar_lisp_nopro (namestring, address)
     char *namestring;
     Lisp_Object *address;
{
  Lisp_Object sym, val;
  sym = intern (namestring);
  val = allocate_misc ();
  XMISCTYPE (val) = Lisp_Misc_Objfwd;
  XOBJFWD (val)->objvar = address;
  SET_SYMBOL_VALUE (sym, val);
}

void
defvar_lisp (namestring, address)
     char *namestring;
     Lisp_Object *address;
{
  defvar_lisp_nopro (namestring, address);
  staticpro (address);
}

/* Similar but define a variable whose value is the Lisp Object stored in
   the current buffer.  address is the address of the slot in the buffer
   that is current now. */

void
defvar_per_buffer (namestring, address, type, doc)
     char *namestring;
     Lisp_Object *address;
     Lisp_Object type;
     char *doc;
{
  Lisp_Object sym, val;
  int offset;
  extern struct buffer buffer_local_symbols;

  sym = intern (namestring);
  val = allocate_misc ();
  offset = (char *)address - (char *)current_buffer;

  XMISCTYPE (val) = Lisp_Misc_Buffer_Objfwd;
  XBUFFER_OBJFWD (val)->offset = offset;
  SET_SYMBOL_VALUE (sym, val);
  PER_BUFFER_SYMBOL (offset) = sym;
  PER_BUFFER_TYPE (offset) = type;
  
  if (PER_BUFFER_IDX (offset) == 0)
    /* Did a DEFVAR_PER_BUFFER without initializing the corresponding
       slot of buffer_local_flags */
    abort ();
}


/* Similar but define a variable whose value is the Lisp Object stored
   at a particular offset in the current kboard object.  */

void
defvar_kboard (namestring, offset)
     char *namestring;
     int offset;
{
  Lisp_Object sym, val;
  sym = intern (namestring);
  val = allocate_misc ();
  XMISCTYPE (val) = Lisp_Misc_Kboard_Objfwd;
  XKBOARD_OBJFWD (val)->offset = offset;
  SET_SYMBOL_VALUE (sym, val);
}
\f
/* Record the value of load-path used at the start of dumping
   so we can see if the site changed it later during dumping.  */
static Lisp_Object dump_path;

void
init_lread ()
{
  char *normal;
  int turn_off_warning = 0;

  /* Compute the default load-path.  */
#ifdef CANNOT_DUMP
  normal = PATH_LOADSEARCH;
  Vload_path = decode_env_path (0, normal);
#else
  if (NILP (Vpurify_flag))
    normal = PATH_LOADSEARCH;
  else
    normal = PATH_DUMPLOADSEARCH;

  /* In a dumped Emacs, we normally have to reset the value of
     Vload_path from PATH_LOADSEARCH, since the value that was dumped
     uses ../lisp, instead of the path of the installed elisp
     libraries.  However, if it appears that Vload_path was changed
     from the default before dumping, don't override that value.  */
  if (initialized)
    {
      if (! NILP (Fequal (dump_path, Vload_path)))
        {
          Vload_path = decode_env_path (0, normal);
          if (!NILP (Vinstallation_directory))
            {
              Lisp_Object tem, tem1, sitelisp;

              /* Remove site-lisp dirs from path temporarily and store
                 them in sitelisp, then conc them on at the end so
                 they're always first in path.  */
              sitelisp = Qnil;
              while (1)
                {
                  tem = Fcar (Vload_path);
                  tem1 = Fstring_match (build_string ("site-lisp"),
                                        tem, Qnil);
                  if (!NILP (tem1))
                    {
                      Vload_path = Fcdr (Vload_path);
                      sitelisp = Fcons (tem, sitelisp);
                    }
                  else
                    break;
                }

              /* Add to the path the lisp subdir of the
                 installation dir, if it exists.  */
              tem = Fexpand_file_name (build_string ("lisp"),
                                       Vinstallation_directory);
              tem1 = Ffile_exists_p (tem);
              if (!NILP (tem1))
                {
                  if (NILP (Fmember (tem, Vload_path)))
                    {
                      turn_off_warning = 1;
                      Vload_path = Fcons (tem, Vload_path);
                    }
                }
              else
                /* That dir doesn't exist, so add the build-time
                   Lisp dirs instead.  */
                Vload_path = nconc2 (Vload_path, dump_path);

              /* Add leim under the installation dir, if it exists.  */
              tem = Fexpand_file_name (build_string ("leim"),
                                       Vinstallation_directory);
              tem1 = Ffile_exists_p (tem);
              if (!NILP (tem1))
                {
                  if (NILP (Fmember (tem, Vload_path)))
                    Vload_path = Fcons (tem, Vload_path);
                }

              /* Add site-list under the installation dir, if it exists.  */
              tem = Fexpand_file_name (build_string ("site-lisp"),
                                       Vinstallation_directory);
              tem1 = Ffile_exists_p (tem);
              if (!NILP (tem1))
                {
                  if (NILP (Fmember (tem, Vload_path)))
                    Vload_path = Fcons (tem, Vload_path);
                }

              /* If Emacs was not built in the source directory,
                 and it is run from where it was built, add to load-path
                 the lisp, leim and site-lisp dirs under that directory.  */

              if (NILP (Fequal (Vinstallation_directory, Vsource_directory)))
                {
                  Lisp_Object tem2;

                  tem = Fexpand_file_name (build_string ("src/Makefile"),
                                           Vinstallation_directory);
                  tem1 = Ffile_exists_p (tem);

                  /* Don't be fooled if they moved the entire source tree
                     AFTER dumping Emacs.  If the build directory is indeed
                     different from the source dir, src/Makefile.in and
                     src/Makefile will not be found together.  */
                  tem = Fexpand_file_name (build_string ("src/Makefile.in"),
                                           Vinstallation_directory);
                  tem2 = Ffile_exists_p (tem);
                  if (!NILP (tem1) && NILP (tem2))
                    {
                      tem = Fexpand_file_name (build_string ("lisp"),
                                               Vsource_directory);

                      if (NILP (Fmember (tem, Vload_path)))
                        Vload_path = Fcons (tem, Vload_path);

                      tem = Fexpand_file_name (build_string ("leim"),
                                               Vsource_directory);

                      if (NILP (Fmember (tem, Vload_path)))
                        Vload_path = Fcons (tem, Vload_path);

                      tem = Fexpand_file_name (build_string ("site-lisp"),
                                               Vsource_directory);

                      if (NILP (Fmember (tem, Vload_path)))
                        Vload_path = Fcons (tem, Vload_path);
                    }
                }
              if (!NILP (sitelisp))
                Vload_path = nconc2 (Fnreverse (sitelisp), Vload_path);
            }
        }
    }
  else
    {
      /* NORMAL refers to the lisp dir in the source directory.  */
      /* We used to add ../lisp at the front here, but
         that caused trouble because it was copied from dump_path
         into Vload_path, aboe, when Vinstallation_directory was non-nil.
         It should be unnecessary.  */
      Vload_path = decode_env_path (0, normal);
      dump_path = Vload_path;
    }
#endif

#ifndef WINDOWSNT
  /* When Emacs is invoked over network shares on NT, PATH_LOADSEARCH is 
     almost never correct, thereby causing a warning to be printed out that 
     confuses users.  Since PATH_LOADSEARCH is always overridden by the
     EMACSLOADPATH environment variable below, disable the warning on NT.  */

  /* Warn if dirs in the *standard* path don't exist.  */
  if (!turn_off_warning)
    {
      Lisp_Object path_tail;

      for (path_tail = Vload_path;
           !NILP (path_tail);
           path_tail = XCDR (path_tail))
        {
          Lisp_Object dirfile;
          dirfile = Fcar (path_tail);
          if (STRINGP (dirfile))
            {
              dirfile = Fdirectory_file_name (dirfile);
              if (access (SDATA (dirfile), 0) < 0)
                dir_warning ("Warning: Lisp directory `%s' does not exist.\n",
                             XCAR (path_tail));
            }
        }
    }
#endif /* WINDOWSNT */

  /* If the EMACSLOADPATH environment variable is set, use its value.
     This doesn't apply if we're dumping.  */
#ifndef CANNOT_DUMP
  if (NILP (Vpurify_flag)
      && egetenv ("EMACSLOADPATH"))
#endif
    Vload_path = decode_env_path ("EMACSLOADPATH", normal);

  Vvalues = Qnil;

  load_in_progress = 0;
  Vload_file_name = Qnil;

  load_descriptor_list = Qnil;

  Vstandard_input = Qt;
  Vloads_in_progress = Qnil;
}

/* Print a warning, using format string FORMAT, that directory DIRNAME
   does not exist.  Print it on stderr and put it in *Message*.  */

void
dir_warning (format, dirname)
     char *format;
     Lisp_Object dirname;
{
  char *buffer
    = (char *) alloca (SCHARS (dirname) + strlen (format) + 5);

  fprintf (stderr, format, SDATA (dirname));
  sprintf (buffer, format, SDATA (dirname));
  /* Don't log the warning before we've initialized!! */
  if (initialized)
    message_dolog (buffer, strlen (buffer), 0, STRING_MULTIBYTE (dirname));
}

void
syms_of_lread ()
{
  defsubr (&Sread);
  defsubr (&Sread_from_string);
  defsubr (&Sintern);
  defsubr (&Sintern_soft);
  defsubr (&Sunintern);
  defsubr (&Sload);
  defsubr (&Seval_buffer);
  defsubr (&Seval_region);
  defsubr (&Sread_char);
  defsubr (&Sread_char_exclusive);
  defsubr (&Sread_event);
  defsubr (&Sget_file_char);
  defsubr (&Smapatoms);
  defsubr (&Slocate_file_internal);

  DEFVAR_LISP ("obarray", &Vobarray,
               doc: /* Symbol table for use by `intern' and `read'.
It is a vector whose length ought to be prime for best results.
The vector's contents don't make sense if examined from Lisp programs;
to find all the symbols in an obarray, use `mapatoms'.  */);

  DEFVAR_LISP ("values", &Vvalues,
               doc: /* List of values of all expressions which were read, evaluated and printed.
Order is reverse chronological.  */);

  DEFVAR_LISP ("standard-input", &Vstandard_input,
               doc: /* Stream for read to get input from.
See documentation of `read' for possible values.  */);
  Vstandard_input = Qt;

  DEFVAR_LISP ("read-with-symbol-positions", &Vread_with_symbol_positions,
               doc: /* If non-nil, add position of read symbols to `read-symbol-positions-list'.

If this variable is a buffer, then only forms read from that buffer
will be added to `read-symbol-positions-list'.
If this variable is t, then all read forms will be added.
The effect of all other values other than nil are not currently
defined, although they may be in the future.

The positions are relative to the last call to `read' or
`read-from-string'.  It is probably a bad idea to set this variable at
the toplevel; bind it instead. */);
  Vread_with_symbol_positions = Qnil;

  DEFVAR_LISP ("read-symbol-positions-list", &Vread_symbol_positions_list,
               doc: /* A list mapping read symbols to their positions.
This variable is modified during calls to `read' or
`read-from-string', but only when `read-with-symbol-positions' is
non-nil.

Each element of the list looks like (SYMBOL . CHAR-POSITION), where
CHAR-POSITION is an integer giving the offset of that occurrence of the
symbol from the position where `read' or `read-from-string' started.

Note that a symbol will appear multiple times in this list, if it was
read multiple times.  The list is in the same order as the symbols
were read in. */);
  Vread_symbol_positions_list = Qnil;  

  DEFVAR_LISP ("load-path", &Vload_path,
               doc: /* *List of directories to search for files to load.
Each element is a string (directory name) or nil (try default directory).
Initialized based on EMACSLOADPATH environment variable, if any,
otherwise to default specified by file `epaths.h' when Emacs was built.  */);

  DEFVAR_LISP ("load-suffixes", &Vload_suffixes,
               doc: /* *List of suffixes to try for files to load.
This list should not include the empty string.  */);
  Vload_suffixes = Fcons (build_string (".elc"),
                          Fcons (build_string (".el"), Qnil));
  /* We don't use empty_string because it's not initialized yet.  */
  default_suffixes = Fcons (build_string (""), Qnil);
  staticpro (&default_suffixes);

  DEFVAR_BOOL ("load-in-progress", &load_in_progress,
               doc: /* Non-nil iff inside of `load'.  */);

  DEFVAR_LISP ("after-load-alist", &Vafter_load_alist,
               doc: /* An alist of expressions to be evalled when particular files are loaded.
Each element looks like (FILENAME FORMS...).
When `load' is run and the file-name argument is FILENAME,
the FORMS in the corresponding element are executed at the end of loading.

FILENAME must match exactly!  Normally FILENAME is the name of a library,
with no directory specified, since that is how `load' is normally called.
An error in FORMS does not undo the load,
but does prevent execution of the rest of the FORMS.
FILENAME can also be a symbol (a feature) and FORMS are then executed
when the corresponding call to `provide' is made.  */);
  Vafter_load_alist = Qnil;

  DEFVAR_LISP ("load-history", &Vload_history,
               doc: /* Alist mapping source file names to symbols and features.
Each alist element is a list that starts with a file name,
except for one element (optional) that starts with nil and describes
definitions evaluated from buffers not visiting files.
The remaining elements of each list are symbols defined as functions,
and cons cells of the form `(provide . FEATURE)', `(require . FEATURE)',
`(defvar . VARIABLE), `(autoload . SYMBOL)', and `(t . SYMBOL)'.
An element `(t . SYMBOL)' precedes an entry that is just SYMBOL,
and means that SYMBOL was an autoload before this file redefined it
as a function.  */);
  Vload_history = Qnil;

  DEFVAR_LISP ("load-file-name", &Vload_file_name,
               doc: /* Full name of file being loaded by `load'.  */);
  Vload_file_name = Qnil;

  DEFVAR_LISP ("user-init-file", &Vuser_init_file,
               doc: /* File name, including directory, of user's initialization file.
If the file loaded had extension `.elc' and there was a corresponding `.el'
file, this variable contains the name of the .el file, suitable for use
by functions like `custom-save-all' which edit the init file.  */);
  Vuser_init_file = Qnil;

  DEFVAR_LISP ("current-load-list", &Vcurrent_load_list,
               doc: /* Used for internal purposes by `load'.  */);
  Vcurrent_load_list = Qnil;

  DEFVAR_LISP ("load-read-function", &Vload_read_function,
               doc: /* Function used by `load' and `eval-region' for reading expressions.
The default is nil, which means use the function `read'.  */);
  Vload_read_function = Qnil;

  DEFVAR_LISP ("load-source-file-function", &Vload_source_file_function,
               doc: /* Function called in `load' for loading an Emacs lisp source file.
This function is for doing code conversion before reading the source file.
If nil, loading is done without any code conversion.
Arguments are FULLNAME, FILE, NOERROR, NOMESSAGE, where
 FULLNAME is the full name of FILE.
See `load' for the meaning of the remaining arguments.  */);
  Vload_source_file_function = Qnil;

  DEFVAR_BOOL ("load-force-doc-strings", &load_force_doc_strings,
               doc: /* Non-nil means `load' should force-load all dynamic doc strings.
This is useful when the file being loaded is a temporary copy.  */);
  load_force_doc_strings = 0;

  DEFVAR_BOOL ("load-convert-to-unibyte", &load_convert_to_unibyte,
               doc: /* Non-nil means `read' converts strings to unibyte whenever possible.
This is normally bound by `load' and `eval-buffer' to control `read',
and is not meant for users to change.  */);
  load_convert_to_unibyte = 0;

  DEFVAR_LISP ("source-directory", &Vsource_directory,
               doc: /* Directory in which Emacs sources were found when Emacs was built.
You cannot count on them to still be there!  */);
  Vsource_directory
    = Fexpand_file_name (build_string ("../"),
                         Fcar (decode_env_path (0, PATH_DUMPLOADSEARCH)));

  DEFVAR_LISP ("preloaded-file-list", &Vpreloaded_file_list,
               doc: /* List of files that were preloaded (when dumping Emacs).  */);
  Vpreloaded_file_list = Qnil;

  DEFVAR_LISP ("byte-boolean-vars", &Vbyte_boolean_vars,
               doc: /* List of all DEFVAR_BOOL variables, used by the byte code optimizer.  */);
  Vbyte_boolean_vars = Qnil;

  DEFVAR_BOOL ("load-dangerous-libraries", &load_dangerous_libraries,
               doc: /* Non-nil means load dangerous compiled Lisp files.
Some versions of XEmacs use different byte codes than Emacs.  These
incompatible byte codes can make Emacs crash when it tries to execute
them.  */);
  load_dangerous_libraries = 0;

  DEFVAR_LISP ("bytecomp-version-regexp", &Vbytecomp_version_regexp,
               doc: /* Regular expression matching safe to load compiled Lisp files.
When Emacs loads a compiled Lisp file, it reads the first 512 bytes
from the file, and matches them against this regular expression.
When the regular expression matches, the file is considered to be safe
to load.  See also `load-dangerous-libraries'.  */);
  Vbytecomp_version_regexp
    = build_string ("^;;;.\\(in Emacs version\\|bytecomp version FSF\\)");

  /* Vsource_directory was initialized in init_lread.  */

  load_descriptor_list = Qnil;
  staticpro (&load_descriptor_list);

  Qcurrent_load_list = intern ("current-load-list");
  staticpro (&Qcurrent_load_list);

  Qstandard_input = intern ("standard-input");
  staticpro (&Qstandard_input);

  Qread_char = intern ("read-char");
  staticpro (&Qread_char);

  Qget_file_char = intern ("get-file-char");
  staticpro (&Qget_file_char);

  Qbackquote = intern ("`");
  staticpro (&Qbackquote);
  Qcomma = intern (",");
  staticpro (&Qcomma);
  Qcomma_at = intern (",@");
  staticpro (&Qcomma_at);
  Qcomma_dot = intern (",.");
  staticpro (&Qcomma_dot);

  Qinhibit_file_name_operation = intern ("inhibit-file-name-operation");
  staticpro (&Qinhibit_file_name_operation);

  Qascii_character = intern ("ascii-character");
  staticpro (&Qascii_character);

  Qfunction = intern ("function");
  staticpro (&Qfunction);

  Qload = intern ("load");
  staticpro (&Qload);

  Qload_file_name = intern ("load-file-name");
  staticpro (&Qload_file_name);

  staticpro (&dump_path);

  staticpro (&read_objects);
  read_objects = Qnil;
  staticpro (&seen_list);
  
  Vloads_in_progress = Qnil;
  staticpro (&Vloads_in_progress);
}