/* xgettext librep backend.
   Copyright (C) 2001-2003, 2005-2006 Free Software Foundation, Inc.

   This file was written by Bruno Haible <haible@clisp.cons.org>, 2001.

   This program 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.

   This program 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 this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "c-ctype.h"
#include "message.h"
#include "xgettext.h"
#include "x-librep.h"
#include "error.h"
#include "xalloc.h"
#include "exit.h"
#include "hash.h"
#include "gettext.h"

#define _(s) gettext(s)


/* Summary of librep syntax:
   - ';' starts a comment until end of line.
   - Block comments start with '#|' and end with '|#'.
   - Numbers are constituted of an optional prefix (#b, #B for binary,
     #o, #O for octal, #d, #D for decimal, #x, #X for hexadecimal,
     #e, #E for exact, #i, #I for inexact), an optional sign (+ or -), and
     the digits.
   - Characters are written as '?' followed by the character, possibly
     with an escape sequence, for examples '?a', '?\n', '?\177'.
   - Strings are delimited by double quotes. Backslash introduces an escape
     sequence. The following are understood: '\n', '\r', '\f', '\t', '\a',
     '\\', '\^C', '\012' (octal), '\x12' (hexadecimal).
   - Symbols: can contain meta-characters - whitespace or any from ()[]'";|\' -
     if preceded by backslash or enclosed in |...|.
   - Keywords: written as #:SYMBOL.
   - () delimit lists.
   - [] delimit vectors.
   The reader is implemented in librep-0.14/src/lisp.c.  */


/* ====================== Keyword set customization.  ====================== */

/* If true extract all strings.  */
static bool extract_all = false;

static hash_table keywords;
static bool default_keywords = true;


void
x_librep_extract_all ()
{
  extract_all = true;
}


void
x_librep_keyword (const char *name)
{
  if (name == NULL)
    default_keywords = false;
  else
    {
      const char *end;
      struct callshape shape;
      const char *colon;

      if (keywords.table == NULL)
	hash_init (&keywords, 100);

      split_keywordspec (name, &end, &shape);

      /* The characters between name and end should form a valid Lisp
	 symbol.  */
      colon = strchr (name, ':');
      if (colon == NULL || colon >= end)
	insert_keyword_callshape (&keywords, name, end - name, &shape);
    }
}

/* Finish initializing the keywords hash table.
   Called after argument processing, before each file is processed.  */
static void
init_keywords ()
{
  if (default_keywords)
    {
      /* When adding new keywords here, also update the documentation in
	 xgettext.texi!  */
      x_librep_keyword ("_");
      default_keywords = false;
    }
}

void
init_flag_table_librep ()
{
  xgettext_record_flag ("_:1:pass-librep-format");
  xgettext_record_flag ("format:2:librep-format");
}


/* ======================== Reading of characters.  ======================== */

/* Real filename, used in error messages about the input file.  */
static const char *real_file_name;

/* Logical filename and line number, used to label the extracted messages.  */
static char *logical_file_name;
static int line_number;

/* The input file stream.  */
static FILE *fp;


/* Fetch the next character from the input file.  */
static int
do_getc ()
{
  int c = getc (fp);

  if (c == EOF)
    {
      if (ferror (fp))
	error (EXIT_FAILURE, errno, _("\
error while reading \"%s\""), real_file_name);
    }
  else if (c == '\n')
   line_number++;

  return c;
}

/* Put back the last fetched character, not EOF.  */
static void
do_ungetc (int c)
{
  if (c == '\n')
    line_number--;
  ungetc (c, fp);
}


/* ========================== Reading of tokens.  ========================== */


/* A token consists of a sequence of characters.  */
struct token
{
  int allocated;		/* number of allocated 'token_char's */
  int charcount;		/* number of used 'token_char's */
  char *chars;			/* the token's constituents */
};

/* Initialize a 'struct token'.  */
static inline void
init_token (struct token *tp)
{
  tp->allocated = 10;
  tp->chars = (char *) xmalloc (tp->allocated * sizeof (char));
  tp->charcount = 0;
}

/* Free the memory pointed to by a 'struct token'.  */
static inline void
free_token (struct token *tp)
{
  free (tp->chars);
}

/* Ensure there is enough room in the token for one more character.  */
static inline void
grow_token (struct token *tp)
{
  if (tp->charcount == tp->allocated)
    {
      tp->allocated *= 2;
      tp->chars = (char *) xrealloc (tp->chars, tp->allocated * sizeof (char));
    }
}

/* Read the next token.  If 'first' is given, it points to the first
   character, which has already been read.  Returns true for a symbol,
   false for a number.  */
static bool
read_token (struct token *tp, const int *first)
{
  int c;
  /* Variables for speculative number parsing:  */
  int radix = -1;
  int nfirst = 0;
  bool exact = true;
  bool rational = false;
  bool exponent = false;
  bool had_sign = false;
  bool expecting_prefix = false;

  init_token (tp);

  if (first)
    c = *first;
  else
    c = do_getc ();

  for (;; c = do_getc ())
    {
      switch (c)
	{
	case EOF:
	  goto done;

	case ' ': case '\t': case '\n': case '\f': case '\r':
	case '(': case ')': case '[': case ']':
	case '\'': case '"': case ';': case ',': case '`':
	  goto done;

	case '\\':
	  radix = 0;
	  c = do_getc ();
	  if (c == EOF)
	    /* Invalid, but be tolerant.  */
	    break;
	  grow_token (tp);
	  tp->chars[tp->charcount++] = c;
	  break;

	case '|':
	  radix = 0;
	  for (;;)
	    {
	      c = do_getc ();
	      if (c == EOF || c == '|')
		break;
	      grow_token (tp);
	      tp->chars[tp->charcount++] = c;
	    }
	  break;

	default:
	  if (radix != 0)
	    {
	      if (expecting_prefix)
		{
		  switch (c)
		    {
		    case 'B': case 'b':
		      radix = 2;
		      break;
		    case 'O': case 'o':
		      radix = 8;
		      break;
		    case 'D': case 'd':
		      radix = 10;
		      break;
		    case 'X': case 'x':
		      radix = 16;
		      break;
		    case 'E': case 'e':
		    case 'I': case 'i':
		      break;
		    default:
		      radix = 0;
		      break;
		    }
		  expecting_prefix = false;
		  nfirst = tp->charcount + 1;
		}
	      else if (tp->charcount == nfirst
		       && (c == '+' || c == '-' || c == '#'))
		{
		  if (c == '#')
		    {
		      if (had_sign)
			radix = 0;
		      else
			expecting_prefix = true;
		    }
		  else
		    had_sign = true;
		  nfirst = tp->charcount + 1;
		}
	      else
		{
		  switch (radix)
		    {
		    case -1:
		      if (c == '.')
			{
			  radix = 10;
			  exact = false;
			}
		      else if (!(c >= '0' && c <= '9'))
			radix = 0;
		      else if (c == '0')
			radix = 1;
		      else
			radix = 10;
		      break;

		    case 1:
		      switch (c)
			{
			case 'X': case 'x':
			  radix = 16;
			  nfirst = tp->charcount + 1;
			  break;
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7':
			  radix = 8;
			  nfirst = tp->charcount;
			  break;
			case '.': case 'E': case 'e':
			  radix = 10;
			  exact = false;
			  break;
			case '/':
			  radix = 10;
			  rational = true;
			  break;
			default:
			  radix = 0;
			  break;
			}
		      break;

		    default:
		      switch (c)
			{
			case '.':
			  if (exact && radix == 10 && !rational)
			    exact = false;
			  else
			    radix = 0;
			  break;
			case '/':
			  if (exact && !rational)
			    rational = true;
			  else
			    radix = 0;
			  break;
			case 'E': case 'e':
			  if (radix == 10)
			    {
			      if (!rational && !exponent)
				{
				  exponent = true;
				  exact = false;
				}
			      else
				radix = 0;
			      break;
			    }
			  /*FALLTHROUGH*/
			default:
			  if (exponent && (c == '+' || c == '-'))
			    break;
			  if ((radix <= 10
			       && !(c >= '0' && c <= '0' + radix - 1))
			      || (radix == 16 && !c_isxdigit (c)))
			    radix = 0;
			  break;
			}
		      break;
		    }
		}
	    }
	  else
	    {
	      if (c == '#')
		goto done;
	    }
	  grow_token (tp);
	  tp->chars[tp->charcount++] = c;
	}
    }
 done:
  if (c != EOF)
    do_ungetc (c);
  if (radix > 0 && nfirst < tp->charcount)
    return false; /* number */
  else
    return true; /* symbol */
}


/* ========================= Accumulating comments ========================= */


static char *buffer;
static size_t bufmax;
static size_t buflen;

static inline void
comment_start ()
{
  buflen = 0;
}

static inline void
comment_add (int c)
{
  if (buflen >= bufmax)
    {
      bufmax = 2 * bufmax + 10;
      buffer = xrealloc (buffer, bufmax);
    }
  buffer[buflen++] = c;
}

static inline void
comment_line_end (size_t chars_to_remove)
{
  buflen -= chars_to_remove;
  while (buflen >= 1
	 && (buffer[buflen - 1] == ' ' || buffer[buflen - 1] == '\t'))
    --buflen;
  if (chars_to_remove == 0 && buflen >= bufmax)
    {
      bufmax = 2 * bufmax + 10;
      buffer = xrealloc (buffer, bufmax);
    }
  buffer[buflen] = '\0';
  savable_comment_add (buffer);
}


/* These are for tracking whether comments count as immediately before
   keyword.  */
static int last_comment_line;
static int last_non_comment_line;


/* ========================= Accumulating messages ========================= */


static message_list_ty *mlp;


/* ============== Reading of objects.  See CLHS 2 "Syntax".  ============== */


/* We are only interested in symbols (e.g. GETTEXT or NGETTEXT) and strings.
   Other objects need not to be represented precisely.  */
enum object_type
{
  t_symbol,	/* symbol */
  t_string,	/* string */
  t_other,	/* other kind of real object */
  t_dot,	/* '.' pseudo object */
  t_close,	/* ')' or ']' pseudo object */
  t_eof		/* EOF marker */
};

struct object
{
  enum object_type type;
  struct token *token;		/* for t_symbol and t_string */
  int line_number_at_start;	/* for t_string */
};

/* Free the memory pointed to by a 'struct object'.  */
static inline void
free_object (struct object *op)
{
  if (op->type == t_symbol || op->type == t_string)
    {
      free_token (op->token);
      free (op->token);
    }
}

/* Convert a t_symbol/t_string token to a char*.  */
static char *
string_of_object (const struct object *op)
{
  char *str;
  int n;

  if (!(op->type == t_symbol || op->type == t_string))
    abort ();
  n = op->token->charcount;
  str = (char *) xmalloc (n + 1);
  memcpy (str, op->token->chars, n);
  str[n] = '\0';
  return str;
}

/* Context lookup table.  */
static flag_context_list_table_ty *flag_context_list_table;

/* Returns the character represented by an escape sequence.  */
static int
do_getc_escaped (int c)
{
  switch (c)
    {
    case 'n':
      return '\n';
    case 'r':
      return '\r';
    case 'f':
      return '\f';
    case 't':
      return '\t';
    case 'v':
      return '\v';
    case 'a':
      return '\a';
    case '^':
      c = do_getc ();
      if (c == EOF)
	return EOF;
      return c & 0x1f;
    case '0': case '1': case '2': case '3': case '4':
    case '5': case '6': case '7':
      {
	int n = c - '0';

	c = do_getc ();
	if (c != EOF)
	  {
	    if (c >= '0' && c <= '7')
	      {
		n = (n << 3) + (c - '0');
		c = do_getc ();
		if (c != EOF)
		  {
		    if (c >= '0' && c <= '7')
		      n = (n << 3) + (c - '0');
		    else
		      do_ungetc (c);
		  }
	      }
	    else
	      do_ungetc (c);
	  }
	return (unsigned char) n;
      }
    case 'x':
      {
	int n = 0;

	for (;;)
	  {
	    c = do_getc ();
	    if (c == EOF)
	      break;
	    else if (c >= '0' && c <= '9')
	      n = (n << 4) + (c - '0');
	    else if (c >= 'A' && c <= 'F')
	      n = (n << 4) + (c - 'A' + 10);
	    else if (c >= 'a' && c <= 'f')
	      n = (n << 4) + (c - 'a' + 10);
	    else
	      {
		do_ungetc (c);
		break;
	      }
	  }
	return (unsigned char) n;
      }
    default:
      return c;
    }
}

/* Read the next object.  */
static void
read_object (struct object *op, flag_context_ty outer_context)
{
  for (;;)
    {
      int c;

      c = do_getc ();

      switch (c)
	{
	case EOF:
	  op->type = t_eof;
	  return;

	case '\n':
	  /* Comments assumed to be grouped with a message must immediately
	     precede it, with no non-whitespace token on a line between
	     both.  */
	  if (last_non_comment_line > last_comment_line)
	    savable_comment_reset ();
	  continue;

	case ' ': case '\t': case '\f': case '\r':
	  continue;

	case '(':
	  {
	    int arg = 0;		/* Current argument number.  */
	    flag_context_list_iterator_ty context_iter;
	    const struct callshapes *shapes = NULL;
	    struct arglist_parser *argparser = NULL;

	    for (;; arg++)
	      {
		struct object inner;
		flag_context_ty inner_context;

		if (arg == 0)
		  inner_context = null_context;
		else
		  inner_context =
		    inherited_context (outer_context,
				       flag_context_list_iterator_advance (
					 &context_iter));

		read_object (&inner, inner_context);

		/* Recognize end of list.  */
		if (inner.type == t_close)
		  {
		    op->type = t_other;
		    /* Don't bother converting "()" to "NIL".  */
		    last_non_comment_line = line_number;
		    if (argparser != NULL)
		      arglist_parser_done (argparser, arg);
		    return;
		  }

		/* Dots are not allowed in every position.
		   But be tolerant.  */

		/* EOF inside list is illegal.  But be tolerant.  */
		if (inner.type == t_eof)
		  break;

		if (arg == 0)
		  {
		    /* This is the function position.  */
		    if (inner.type == t_symbol)
		      {
			char *symbol_name = string_of_object (&inner);
			void *keyword_value;

			if (hash_find_entry (&keywords,
					     symbol_name, strlen (symbol_name),
					     &keyword_value)
			    == 0)
			  shapes = (const struct callshapes *) keyword_value;

			argparser = arglist_parser_alloc (mlp, shapes);

			context_iter =
			  flag_context_list_iterator (
			    flag_context_list_table_lookup (
			      flag_context_list_table,
			      symbol_name, strlen (symbol_name)));

			free (symbol_name);
		      }
		    else
		      context_iter = null_context_list_iterator;
		  }
		else
		  {
		    /* These are the argument positions.  */
		    if (argparser != NULL && inner.type == t_string)
		      arglist_parser_remember (argparser, arg,
					       string_of_object (&inner),
					       inner_context,
					       logical_file_name,
					       inner.line_number_at_start,
					       savable_comment);
		  }

		free_object (&inner);
	      }

	    if (argparser != NULL)
	      arglist_parser_done (argparser, arg);
	  }
	  op->type = t_other;
	  last_non_comment_line = line_number;
	  return;

	case '[':
	  {
	    for (;;)
	      {
		struct object inner;

		read_object (&inner, null_context);

		/* Recognize end of vector.  */
		if (inner.type == t_close)
		  {
		    op->type = t_other;
		    last_non_comment_line = line_number;
		    return;
		  }

		/* Dots are not allowed.  But be tolerant.  */

		/* EOF inside vector is illegal.  But be tolerant.  */
		if (inner.type == t_eof)
		  break;

		free_object (&inner);
	      }
	  }
	  op->type = t_other;
	  last_non_comment_line = line_number;
	  return;

	case ')': case ']':
	  /* Tell the caller about the end of list or vector.
	     Unmatched closing parenthesis is illegal.  But be tolerant.  */
	  op->type = t_close;
	  last_non_comment_line = line_number;
	  return;

	case ',':
	  {
	    int c = do_getc ();
	    /* The ,@ handling inside lists is wrong anyway, because
	       ,@form expands to an unknown number of elements.  */
	    if (c != EOF && c != '@')
	      do_ungetc (c);
	  }
	  /*FALLTHROUGH*/
	case '\'':
	case '`':
	  {
	    struct object inner;

	    read_object (&inner, null_context);

	    /* Dots and EOF are not allowed here.  But be tolerant.  */

	    free_object (&inner);

	    op->type = t_other;
	    last_non_comment_line = line_number;
	    return;
	  }

	case ';':
	  {
	    bool all_semicolons = true;

	    last_comment_line = line_number;
	    comment_start ();
	    for (;;)
	      {
		int c = do_getc ();
		if (c == EOF || c == '\n' || c == '\f' || c == '\r')
		  break;
		if (c != ';')
		  all_semicolons = false;
		if (!all_semicolons)
		  {
		    /* We skip all leading white space, but not EOLs.  */
		    if (!(buflen == 0 && (c == ' ' || c == '\t')))
		      comment_add (c);
		  }
	      }
	    comment_line_end (0);
	    continue;
	  }

	case '"':
	  {
	    op->token = (struct token *) xmalloc (sizeof (struct token));
	    init_token (op->token);
	    op->line_number_at_start = line_number;
	    for (;;)
	      {
		int c = do_getc ();
		if (c == EOF)
		  /* Invalid input.  Be tolerant, no error message.  */
		  break;
		if (c == '"')
		  break;
		if (c == '\\')
		  {
		    c = do_getc ();
		    if (c == EOF)
		      /* Invalid input.  Be tolerant, no error message.  */
		      break;
		    if (c == '\n')
		      /* Ignore escaped newline.  */
		      ;
		    else
		      {
			c = do_getc_escaped (c);
			if (c == EOF)
			  /* Invalid input.  Be tolerant, no error message.  */
			  break;
			grow_token (op->token);
			op->token->chars[op->token->charcount++] = c;
		      }
		  }
		else
		  {
		    grow_token (op->token);
		    op->token->chars[op->token->charcount++] = c;
		  }
	      }
	    op->type = t_string;

	    if (extract_all)
	      {
		lex_pos_ty pos;

		pos.file_name = logical_file_name;
		pos.line_number = op->line_number_at_start;
		remember_a_message (mlp, NULL, string_of_object (op),
				    null_context, &pos, savable_comment);
	      }
	    last_non_comment_line = line_number;
	    return;
	  }

	case '?':
	  c = do_getc ();
	  if (c == EOF)
	    /* Invalid input.  Be tolerant, no error message.  */
	    ;
	  else if (c == '\\')
	    {
	      c = do_getc ();
	      if (c == EOF)
		/* Invalid input.  Be tolerant, no error message.  */
		;
	      else
		{
		  c = do_getc_escaped (c);
		  if (c == EOF)
		    /* Invalid input.  Be tolerant, no error message.  */
		    ;
		}
	    }
	  op->type = t_other;
	  last_non_comment_line = line_number;
	  return;

	case '#':
	  /* Dispatch macro handling.  */
	  c = do_getc ();
	  if (c == EOF)
	    /* Invalid input.  Be tolerant, no error message.  */
	    {
	      op->type = t_other;
	      return;
	    }

	  switch (c)
	    {
	    case '!':
	      if (ftell (fp) == 2)
		/* Skip comment until !# */
		{
		  c = do_getc ();
		  for (;;)
		    {
		      if (c == EOF)
			break;
		      if (c == '!')
			{
			  c = do_getc ();
			  if (c == EOF || c == '#')
			    break;
			}
		      else
			c = do_getc ();
		    }
		  if (c == EOF)
		    {
		      /* EOF not allowed here.  But be tolerant.  */
		      op->type = t_eof;
		      return;
		    }
		  continue;
		}
	      /*FALLTHROUGH*/
	    case '\'':
	    case ':':
	      {
		struct object inner;
		read_object (&inner, null_context);
		/* Dots and EOF are not allowed here.
		   But be tolerant.  */
		free_object (&inner);
		op->type = t_other;
		last_non_comment_line = line_number;
		return;
	      }

	    case '[':
	    case '(':
	      {
		struct object inner;
		do_ungetc (c);
		read_object (&inner, null_context);
		/* Dots and EOF are not allowed here.
		   But be tolerant.  */
		free_object (&inner);
		op->type = t_other;
		last_non_comment_line = line_number;
		return;
	      }

	    case '|':
	      {
		int depth = 0;

		comment_start ();
		c = do_getc ();
		for (;;)
		  {
		    if (c == EOF)
		      break;
		    if (c == '|')
		      {
			c = do_getc ();
			if (c == EOF)
			  break;
			if (c == '#')
			  {
			    if (depth == 0)
			      {
				comment_line_end (0);
				break;
			      }
			    depth--;
			    comment_add ('|');
			    comment_add ('#');
			    c = do_getc ();
			  }
			else
			  comment_add ('|');
		      }
		    else if (c == '#')
		      {
			c = do_getc ();
			if (c == EOF)
			  break;
			comment_add ('#');
			if (c == '|')
			  {
			    depth++;
			    comment_add ('|');
			    c = do_getc ();
			  }
		      }
		    else
		      {
			/* We skip all leading white space.  */
			if (!(buflen == 0 && (c == ' ' || c == '\t')))
			  comment_add (c);
			if (c == '\n')
			  {
			    comment_line_end (1);
			    comment_start ();
			  }
			c = do_getc ();
		      }
		  }
		if (c == EOF)
		  {
		    /* EOF not allowed here.  But be tolerant.  */
		    op->type = t_eof;
		    return;
		  }
		last_comment_line = line_number;
		continue;
	      }

	    case '\\':
	      {
		struct token token;
		int first = '\\';
		read_token (&token, &first);
		free_token (&token);
		op->type = t_other;
		last_non_comment_line = line_number;
		return;
	      }

	    case 'T': case 't':
	    case 'F': case 'f':
	      op->type = t_other;
	      last_non_comment_line = line_number;
	      return;

	    case 'B': case 'b':
	    case 'O': case 'o':
	    case 'D': case 'd':
	    case 'X': case 'x':
	    case 'E': case 'e':
	    case 'I': case 'i':
	      {
		struct token token;
		do_ungetc (c);
		c = '#';
		read_token (&token, &c);
		free_token (&token);
		op->type = t_other;
		last_non_comment_line = line_number;
		return;
	      }

	    default:
	      /* Invalid input.  Be tolerant, no error message.  */
	      op->type = t_other;
	      last_non_comment_line = line_number;
	      return;
	    }

	  /*NOTREACHED*/
	  abort ();

	default:
	  /* Read a token.  */
	  {
	    bool symbol;

	    op->token = (struct token *) xmalloc (sizeof (struct token));
	    symbol = read_token (op->token, &c);
	    if (op->token->charcount == 1 && op->token->chars[0] == '.')
	      {
		free_token (op->token);
		free (op->token);
		op->type = t_dot;
		last_non_comment_line = line_number;
		return;
	      }
	    if (!symbol)
	      {
		free_token (op->token);
		free (op->token);
		op->type = t_other;
		last_non_comment_line = line_number;
		return;
	      }
	    /* Distinguish between "foo" and "foo#bar".  */
	    c = do_getc ();
	    if (c == '#')
	      {
		struct token second_token;

		free_token (op->token);
		free (op->token);
		read_token (&second_token, NULL);
		free_token (&second_token);
		op->type = t_other;
		last_non_comment_line = line_number;
		return;
	      }
	    else
	      {
		if (c != EOF)
		  do_ungetc (c);
		op->type = t_symbol;
		last_non_comment_line = line_number;
		return;
	      }
	  }
	}
    }
}


void
extract_librep (FILE *f,
		const char *real_filename, const char *logical_filename,
		flag_context_list_table_ty *flag_table,
		msgdomain_list_ty *mdlp)
{
  mlp = mdlp->item[0]->messages;

  fp = f;
  real_file_name = real_filename;
  logical_file_name = xstrdup (logical_filename);
  line_number = 1;

  last_comment_line = -1;
  last_non_comment_line = -1;

  flag_context_list_table = flag_table;

  init_keywords ();

  /* Eat tokens until eof is seen.  When read_object returns
     due to an unbalanced closing parenthesis, just restart it.  */
  do
    {
      struct object toplevel_object;

      read_object (&toplevel_object, null_context);

      if (toplevel_object.type == t_eof)
	break;

      free_object (&toplevel_object);
    }
  while (!feof (fp));

  /* Close scanner.  */
  fp = NULL;
  real_file_name = NULL;
  logical_file_name = NULL;
  line_number = 0;
}