From: "Bart Schaefer" <schaefer@candle.brasslantern.com>
To: Tanaka Akira <akr@jaist.ac.jp>, zsh-workers@sunsite.auc.dk
Subject: Re: assoc array assignment problem.
Date: Tue, 21 Sep 1999 04:59:34 +0000 [thread overview]
Message-ID: <990921045934.ZM13380@candle.brasslantern.com> (raw)
In-Reply-To: <rsq7lllujs2.fsf@crane.jaist.ac.jp>
On Sep 21, 10:37am, Tanaka Akira wrote:
} Subject: assoc array assignment problem.
}
} Z(2):akr@localhost% Src/zsh -f
} localhost% typeset -A arr
} localhost% a='$b'
} localhost% b='c'
} localhost% arr[$a]=d
} localhost% print -lr - ${(kv)arr}
} c
} d
} localhost%
}
} Hm. Variable expansion is performed twice.
This is not an associative array problem; it affects all arrays. Note:
zagzig<17> q=()
zagzig<18> g=7
zagzig<19> f='$g'
zagzig<20> q[$f]=seven
zagzig<21> print $#q $q
7 seven
zagzig<22>
The first substitution happens at the expected time, during evaluation
of the line. The second one happens at execute time in addvars() --
assignment is implemented as if `x=y somecommand` where somecommand is
null. addvars() calls setsparam(), which discovers that there is no
parameter named "q[$g]" and therefore creates "q" and then makes a call
to getvalue() to retrieve a Value structure for the parameter that it
just created. getvalue() then expands $g (as it would for ${q[$g]} in
which the stuff inside the ${ } has _not_ previously been expanded) and
you get the effect above.
And you can't even protect it with double-quoting, though using single
quotes counterintuitively (but expectedly, given the explaination above)
produces the desired result:
zagzig<26> arr['$a']=d
zagzig<27> print -lr - ${(kv)arr}
$x
d
zagzig<28>
I really have no idea when this got introduced. It might have something
to do with zsh-workers/4826 and follow-ons, back last year; 3.1.5-pws-4
would be it, but I no longer have anything that old around to try.
The right thing would be for the parser to know that it shouldn't expand
inside the [] on the left-hand side of an assignment, thereby delaying
the one interesting expansion to getvalue(); but that may be a bit too
much to bite off ...
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com
next prev parent reply other threads:[~1999-09-21 5:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-09-21 1:37 Tanaka Akira
1999-09-21 4:59 ` Bart Schaefer [this message]
1999-09-28 12:15 ` Peter Stephenson
1999-09-28 13:04 ` Peter Stephenson
1999-09-30 16:58 ` Bart Schaefer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=990921045934.ZM13380@candle.brasslantern.com \
--to=schaefer@candle.brasslantern.com \
--cc=akr@jaist.ac.jp \
--cc=zsh-workers@sunsite.auc.dk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/zsh/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).