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From: et99 <et99@rocketship1.me>
Newsgroups: comp.lang.tcl
Subject: Re: How do I correctly access this variable?
Date: Fri, 4 Oct 2024 12:17:33 -0700
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 <ygay134fdhs.fsf@akutech.de>
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On 10/4/2024 2:01 AM, Ralf Fassel wrote:
> * Colin Macleod <user7@cmacleod.me.uk.invalid>
> | Luc <luc@sep.invalid> posted:
>>
> | > I am stumped by this:
> | >
> | > array set CONTROL {
> | > 	InitialStartUpDir "$env(HOME)"
> | > }
> --<snip-snip>--
> | > What am I doing wrong?
>>
> | Variable references do not get expanded inside braces {}.
> | Try:
> | array set CONTROL "
> | 	InitialStartUpDir $env(HOME)
> | "
> 
> Or safer, in case the expanded value contains spaces:
> 
>    array set CONTROL [list InitialStartUpDir $env(HOME)]
> 
> HTH
> R'

One wonders why Luc wouldn't just simply use array notation:

     set ::CONTROL(InitialStartUpDir) $env(HOME)

[array set] with a list is useful when the list has more than one key/value pair, while with just a single pair takes about twice the time (as determined with [time]} to run.


BTW I have one little nitpick with the docs on this one. It states:

"Each odd-numbered element in list is treated as an element name within arrayName ..."

In Tcl, list indices invariably begin at 0, and yet odd-numbered here would indicate beginning at 1, and oddity in itself :)