unix RC shell bug

unix RC shell bug

[Matt]

after hours of not noticing one of my variables was a list and not a
string (it's 5am I've been on this since 10pm!) I eventually got to
this sorry state.

in good ol' plan9

cpu% t=(1 2 3 6 7)
cpu% echo $#t
5
cpu% echo $"t
1 2 3 6 7

in /usr/local/bin/rc (ver 1.6) on FreeBSD (ver 4.2-RELEASE)

; t=(1 2 3 6 7)
; echo $#t
5
; echo $"t
syntax error


just fyi

Re: unix RC shell bug

[Callum Gibson]

matt@proweb.co.uk writes:
}cpu% echo $"t
}1 2 3 6 7

The list flattening operator is ^ not " in the unix rc. i.e. echo $^t

This is mentioned in the INCOMPATIBILITIES section of the manpage.
Don't know why this is the case, other than to avoid possible confusion
with the meaning of " as a quote char in other unix shells, plus ^ is
used as the concatenation operator anyway as in:
; echo (a b c)^(1 2 3)

(c)2001 Callum Gibson                       callum.gibson@db.com
Global Markets IT, Deutsche Bank, Australia       61 2 9258 1620
### The opinions in this message are mine and not Deutsche's ###

Re: unix RC shell bug

[Decklin Foster]

Matt writes:

> ; echo $"t
> syntax error

It's $^t -- See the INCOMPATIBILITES section in the man page. I am
unsure of the reasons for this, but the ChangeLog notes:

1999-01-05

  Documentation: the Bell Labs rc now has the list flattening operator,
  but spelt $"foo.

-- 
things change.
decklin@red-bean.com

Re: unix RC shell bug

[Smarasderagd]

Byron Rakitzis <byron@rakitzis.com> writes:
>$^ came years before $" was introduced into plan9's rc.
>
>I guess there's no reason not to make Unix rc understand $" as well,
>but it would be important to leave $^ as is.

Ideally, other uses of " should not become syntax errors, although I haven't
taken advantage of it being just another character myself.

Re: unix RC shell bug

[Byron Rakitzis]

$^ came years before $" was introduced into plan9's rc.

I guess there's no reason not to make Unix rc understand $" as well,
but it would be important to leave $^ as is.