Imported from ../bash-2.01.tar.gz.

[thirdparty/bash.git] / 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, 1989, 1991 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
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version.

Bash is distributed in the hope that it will be useful, but WITHOUT ANY
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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; see the file COPYING.  If not, write to the Free Software
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$PRODUCES break.c

$BUILTIN break
$FUNCTION break_builtin
$SHORT_DOC break [n]
Exit from within a FOR, WHILE or UNTIL loop.  If N is specified,
break N levels.
$END
#include <config.h>

#if defined (HAVE_UNISTD_H)
#include <unistd.h>
#endif

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

extern char *this_command_name;

static int check_loop_level ();

/* 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;
{
  int newbreak;

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

  newbreak = get_numeric_arg (list, 1);

  if (newbreak <= 0)
    {
      builtin_error ("loop count must be > 0");
      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 the next iteration of the enclosing FOR, WHILE or UNTIL loop.
If N is specified, resume at the N-th enclosing loop.
$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;
{
  int newcont;

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

  newcont = get_numeric_arg (list, 1);

  if (newcont <= 0)
    {
      builtin_error ("loop count must be > 0");
      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)
    builtin_error ("only meaningful in a `for', `while', or `until' loop");
#endif /* BREAK_COMPLAINS */

  return (loop_level);
}