Subject:      Re: nested arrays redux (plus patch for 8.0a1) - comp.lang.tcl #51338
From:         John Ousterhout <ouster@tcl.Eng.Sun.COM>
Date:         24 Feb 1997

I finally got a chance to look at the following article, which you posted on comp.lang.tcl several weeks ago:

Back in September there was a discussion on "nested arrays". I
posted some test cases showing what did and did not work. John
Ousterhout, fearing that the existing partial ability wasn't clean,
and thus a feature, removed the ability to create them, as of 8.0a1
(originally he planned to do so in 7.6, but at my request he held
off to the major number change).

This note is a follow up to that previous discussion. In particular,
I include the patches necessary to correctly support the previous
"nested array" ability in 8.0a1. My humble request is that the Tcl
team include this minor change in 8.0a2.

I'm still somewhere between ambivalent and negative on this, partly out of fear that there are problems that you haven't foreseen, and partly out of dislike for the change in semantics, particularly the fact that "array get" no longer returns absolutely everything. We'll keep your message around, but there are an awful lot of other things to do that have higher priority, so I can't promise that we'll implement your proposal anytime soon (it almost certainly won't happen in Tcl 8.0). Sorry about that...

Subject:      Re: nested arrays redux (plus patch for 8.0a1) - comp.lang.tcl #51338
From:         John Robert LoVerso <>
To:           John Ousterhout <ouster@tcl.Eng.Sun.COM>
Date:         24 Feb 1997

John -

I'd like to you reconsider that please. The implications are that in 8.0 you've removed one *useful* form of "nested arrays" (via upvar) and left in a useless form of "nested arrays" (via "array set"). This *is* a step backwards. Don't let 8.0 "ship" with this absurdity!

I've leaned on this code all over the place and have yet to find one place where it went wrong. Over the last year I've been bit by horrible bits of Tcl core code (say "sockets" on all platforms) that've done everything from hose my apps to hang my Macintosh. But I've never yet seen a problem from "nested arrays". Besides, the semantics of "nested arrays" have been in there for at least 3 years!