source: trunk/essentials/app-shells/bash/builtins/shift.def

Last change on this file was 3228, checked in by bird, 18 years ago

bash 3.1

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1This file is shift.def, from which is created shift.c.
2It implements the builtin "shift" in Bash.
3
4Copyright (C) 1987-2003 Free Software Foundation, Inc.
5
6This file is part of GNU Bash, the Bourne Again SHell.
7
8Bash is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 2, or (at your option) any later
11version.
12
13Bash is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License along
19with Bash; see the file COPYING. If not, write to the Free Software
20Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.
21
22$PRODUCES shift.c
23
24#include <config.h>
25
26#if defined (HAVE_UNISTD_H)
27# ifdef _MINIX
28# include <sys/types.h>
29# endif
30# include <unistd.h>
31#endif
32
33#include "../bashansi.h"
34#include "../bashintl.h"
35
36#include "../shell.h"
37#include "common.h"
38
39$BUILTIN shift
40$FUNCTION shift_builtin
41$SHORT_DOC shift [n]
42The positional parameters from $N+1 ... are renamed to $1 ... If N is
43not given, it is assumed to be 1.
44$END
45
46int print_shift_error;
47
48/* Shift the arguments ``left''. Shift DOLLAR_VARS down then take one
49 off of REST_OF_ARGS and place it into DOLLAR_VARS[9]. If LIST has
50 anything in it, it is a number which says where to start the
51 shifting. Return > 0 if `times' > $#, otherwise 0. */
52int
53shift_builtin (list)
54 WORD_LIST *list;
55{
56 intmax_t times;
57 register int count;
58 WORD_LIST *temp;
59
60 times = get_numeric_arg (list, 0);
61
62 if (times == 0)
63 return (EXECUTION_SUCCESS);
64 else if (times < 0)
65 {
66 sh_erange (list ? list->word->word : NULL, _("shift count"));
67 return (EXECUTION_FAILURE);
68 }
69 else if (times > number_of_args ())
70 {
71 if (print_shift_error)
72 sh_erange (list ? list->word->word : NULL, _("shift count"));
73 return (EXECUTION_FAILURE);
74 }
75
76 while (times-- > 0)
77 {
78 if (dollar_vars[1])
79 free (dollar_vars[1]);
80
81 for (count = 1; count < 9; count++)
82 dollar_vars[count] = dollar_vars[count + 1];
83
84 if (rest_of_args)
85 {
86 temp = rest_of_args;
87 dollar_vars[9] = savestring (temp->word->word);
88 rest_of_args = rest_of_args->next;
89 temp->next = (WORD_LIST *)NULL;
90 dispose_words (temp);
91 }
92 else
93 dollar_vars[9] = (char *)NULL;
94 }
95 return (EXECUTION_SUCCESS);
96}
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