Date: Wed, 16 Oct 2002 09:30:05 -0700 (PDT) From: Alexandr Kovalenko <never@nevermind.kiev.ua> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/44142: /bin/sh does not support 'command1 & && command2' syntax, which is REQUIRED by POSIX Message-ID: <200210161630.g9GGU5SN054457@freefall.freebsd.org>
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The following reply was made to PR bin/44142; it has been noted by GNATS.
From: Alexandr Kovalenko <never@nevermind.kiev.ua>
To: Garrett Wollman <wollman@lcs.mit.edu>
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: bin/44142: /bin/sh does not support 'command1 & && command2' syntax, which is REQUIRED by POSIX
Date: Wed, 16 Oct 2002 19:26:12 +0300
Hello, Garrett Wollman!
On Wed, Oct 16, 2002 at 11:55:42AM -0400, you wrote:
> > /bin/sh does not support 'command1 & && command2' syntax, which is REQUIRED by POSIX:
>
> Your interpretation is erroneous. The grammar takes precedence over
> the textual description of the syntax, and the grammar is quite clear:
>
> complete_command : list separator
> | list
> ;
> list : list separator_op and_or
> | and_or
> ;
> and_or : pipeline
> | and_or AND_IF linebreak pipeline
> | and_or OR_IF linebreak pipeline
> ;
As we can see from Grammar:
pipeline : pipe_sequence
| Bang pipe_sequence
;
pipe_sequence : command
| pipe_sequence '|' linebreak command
;
So, we can parse 'command1 & && command2' in this way:
'command1 & && command2' : and_or(complete_command(list('command1') separator(' ')) separator_op('&') AND_IF pipeline('command2'))
> The pseudo-syntax `command1 &' can only be resolved by the `list'
> production in the grammar. The `&&' and `||' operators take
> pipelines, and not lists, as operands. See XCU6 page 58.
Yes. It is correct. Sorry for false alert.
--
NEVE-RIPE
Ukrainian FreeBSD User Group
http://uafug.org.ua/
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