* [9fans] Inferno shell
@ 2007-01-02 4:43 lucio
2007-01-08 15:37 ` rog
0 siblings, 1 reply; 2+ messages in thread
From: lucio @ 2007-01-02 4:43 UTC (permalink / raw)
To: 9fans
The Inferno shell man page says about a leading caret in a [ ] class:
(As this character is special to the shell, it may only be
included in a pattern if this character is quoted, as long as
the leading [ is not quoted).
It seems to me that treating the unquoted leading string [^ as a
"token" would be a better alternative. Would it be very difficult to
implement this rather than expect all exclusive classes to start ['^ ?
I presume it is a question of where in the parsing the [ and ^ take
precedence?
++L
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [9fans] Inferno shell
2007-01-02 4:43 [9fans] Inferno shell lucio
@ 2007-01-08 15:37 ` rog
0 siblings, 0 replies; 2+ messages in thread
From: rog @ 2007-01-08 15:37 UTC (permalink / raw)
To: 9fans
[-- Attachment #1: Type: text/plain, Size: 709 bytes --]
you could do that, but it adds a fair amount of awkwardness
into the lexer; i'm not sure that's justified. rc uses ~ instead of ^
for the same reason, which i would have done in the inferno
shell, except that i wished to re-use the existing filepat module.
an alternative might be to scan the pattern before passing
to filepat, substituting [~ by [^; it would be quite simple,
just add something like the following to patquote()
if(word[i] == '[' && i < len word - 1 && word[i+1] == '~')
word[i+1] = '^';
although that does potentially break some existing shell scripts
and it's not clear whether ['^'b] should continue to have
the same meaning.
i'll do this if there's a consensus...
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From: lucio@proxima.alt.za
To: 9fans@cse.psu.edu
Subject: [9fans] Inferno shell
Date: Tue, 2 Jan 2007 06:43:30 +0200
Message-ID: <a6013917637696eaea285a468964b6b6@proxima.alt.za>
The Inferno shell man page says about a leading caret in a [ ] class:
(As this character is special to the shell, it may only be
included in a pattern if this character is quoted, as long as
the leading [ is not quoted).
It seems to me that treating the unquoted leading string [^ as a
"token" would be a better alternative. Would it be very difficult to
implement this rather than expect all exclusive classes to start ['^ ?
I presume it is a question of where in the parsing the [ and ^ take
precedence?
++L
^ permalink raw reply [flat|nested] 2+ messages in thread
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2007-01-02 4:43 [9fans] Inferno shell lucio
2007-01-08 15:37 ` rog
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