i-bash/builtins/break.def

This file is break.def, from which is created break.c.
It implements the builtins "break" and "continue" in Bash.

Copyright (C) 1987-2009 Free Software Foundation, Inc.

This file is part of GNU Bash, the Bourne Again SHell.

Bash 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 3 of the License, or
(at your option) any later version.

Bash 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 Bash.  If not, see <http://www.gnu.org/licenses/>.

$PRODUCES break.c

$BUILTIN break
$FUNCTION break_builtin
$SHORT_DOC break [n]
Exit for, while, or until loops.

Exit a FOR, WHILE or UNTIL loop.  If N is specified, break N enclosing
loops.

Exit Status:
The exit status is 0 unless N is not greater than or equal to 1.
$END
#include <config.h>

#if defined (HAVE_UNISTD_H)
#  ifdef _MINIX
#    include <sys/types.h>
#  endif
#  include <unistd.h>
#endif

#include "../bashintl.h"

#include "../shell.h"
#include "common.h"

extern char *this_command_name;
extern int posixly_correct;

static int check_loop_level __P((void));

/* The depth of while's and until's. */
int loop_level = 0;

/* Non-zero when a "break" instruction is encountered. */
int breaking = 0;

/* Non-zero when we have encountered a continue instruction. */
int continuing = 0;

/* Set up to break x levels, where x defaults to 1, but can be specified
   as the first argument. */
int
break_builtin (list)
     WORD_LIST *list;
{
  intmax_t newbreak;

  CHECK_HELPOPT (list);

  if (check_loop_level () == 0)
    return (EXECUTION_SUCCESS);

  (void)get_numeric_arg (list, 1, &newbreak);

  if (newbreak <= 0)
    {
      sh_erange (list->word->word, _("loop count"));
      breaking = loop_level;
      return (EXECUTION_FAILURE);
    }

  if (newbreak > loop_level)
    newbreak = loop_level;

  breaking = newbreak;

  return (EXECUTION_SUCCESS);
}

$BUILTIN continue
$FUNCTION continue_builtin
$SHORT_DOC continue [n]
Resume for, while, or until loops.

Resumes the next iteration of the enclosing FOR, WHILE or UNTIL loop.
If N is specified, resumes the Nth enclosing loop.

Exit Status:
The exit status is 0 unless N is not greater than or equal to 1.
$END

/* Set up to continue x levels, where x defaults to 1, but can be specified
   as the first argument. */
int
continue_builtin (list)
     WORD_LIST *list;
{
  intmax_t newcont;

  CHECK_HELPOPT (list);

  if (check_loop_level () == 0)
    return (EXECUTION_SUCCESS);

  (void)get_numeric_arg (list, 1, &newcont);

  if (newcont <= 0)
    {
      sh_erange (list->word->word, _("loop count"));
      breaking = loop_level;
      return (EXECUTION_FAILURE);
    }

  if (newcont > loop_level)
    newcont = loop_level;

  continuing = newcont;

  return (EXECUTION_SUCCESS);
}

/* Return non-zero if a break or continue command would be okay.
   Print an error message if break or continue is meaningless here. */
static int
check_loop_level ()
{
#if defined (BREAK_COMPLAINS)
  if (loop_level == 0 && posixly_correct == 0)
    builtin_error (_("only meaningful in a `for', `while', or `until' loop"));
#endif /* BREAK_COMPLAINS */

  return (loop_level);
}