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From: Kragen Javier Sitaker <kragen@canonical.org>
Newsgroups: comp.lang.forth
Subject: Re: dynamic scoping in Forth in one line of code
Date: Sat, 29 Aug 2026 10:50:48 -0300
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Paul Rubin <no.email@nospam.invalid> writes:
> Kragen Javier Sitaker <kragen@canonical.org> writes:
>> A couple of years ago, I noticed that it’s possible to implement
>> Lisp-style dynamic scoping in standard Forth in one line of code:
>>
>>     : (let!) dup @ over swap 2r> rot >r rot >r >r >r ! ; : let! (let!) 2r> ! ;
>
> You need to still restore the old value when the function exits by
> exception or THROW.  So you have to use something like CATCH.

That’s an excellent point, and one I hadn’t considered.  That will
definitely make it more than one line.  How would you implement that?

Kragen