From: Bart Schaefer <schaefer@brasslantern.com>
To: zsh-users@zsh.org
Subject: Re: easy calling of associative array?
Date: Mon, 2 Nov 2015 08:28:08 -0800 [thread overview]
Message-ID: <151102082808.ZM17640@torch.brasslantern.com> (raw)
In-Reply-To: <563784B5.3040901@eastlink.ca>
On Nov 2, 7:43am, Ray Andrews wrote:
}
} get_v ()
} {
} #$3=${(P)${:-${1}[$2]}} #nothing works
} eval "$3=\$${1}[$2]" #this works
} }
This has nothing to do with associative arrays and everything to do with
assignment syntax. "$3" is not a valid identifier, so "$3=" is not an
assignment; this all decided before $3 is expanded, which is why putting
the "eval" around it works (it delays the "is an identifier" check until
after $3 has expanded).
Probably the most cogent way to do this is
get_v () {
typeset -g $3="${(P)${:-${1}[$2]}}"
}
} set_v ()
} {
} # {(P)${:-${1}[$2]}}=$3 #nothing works
} eval "${1}[$2]=$3" #this works
} }
Same assignment-syntax problem.
set_v () {
# typeset -gA $1 # optional
typeset -g "${1}[$2]=$3" # quotes so [ ] isn't globbing
}
Here you don't need the (P) indirection because ${1} and $2 are both
expanded before being passed to typeset, so you already extracted the
name that was passed in $1.
Also note I'm ignoring all possible error checking, e.g. if $1 is not
an identifier (in the worst case, contains an "="), things go badly.
} test_v ()
} {
} #eval "${1}[$2]" #nothing works
} #this works
} [ ${(P)${:-${1}[$2]}} = $3 ] && echo 'all too true' || echo 'alas, no.'
} }
I'm not exactly sure what you're wanting as either output or exit
status here, but except that I'd recommend [[ ]] instead of [ ] as
the test syntax, what you wrote for "this works" is sensible.
next prev parent reply other threads:[~2015-11-02 16:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-01 23:12 Ray Andrews
2015-11-01 23:55 ` ZyX
2015-11-02 0:49 ` Ray Andrews
2015-11-02 3:08 ` Bart Schaefer
2015-11-02 3:33 ` Ray Andrews
2015-11-02 6:51 ` Bart Schaefer
2015-11-02 15:43 ` Ray Andrews
2015-11-02 16:28 ` Bart Schaefer [this message]
2015-11-02 18:32 ` Ray Andrews
2015-11-02 19:37 ` ZyX
2015-11-02 22:10 ` Bart Schaefer
2015-11-02 22:50 ` Ray Andrews
2015-11-02 21:05 ` Bart Schaefer
2015-11-02 23:01 ` Ray Andrews
2015-11-03 15:57 ` Bart Schaefer
2015-11-04 14:48 ` Ray Andrews
2015-11-04 16:39 ` Bart Schaefer
2015-11-04 18:31 ` Ray Andrews
2015-11-02 19:33 ` ZyX
2015-11-02 23:04 ` Ray Andrews
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