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Re: dynamic scoping in Forth in one line of code

From Paul Rubin <no.email@nospam.invalid>
Newsgroups comp.lang.forth
Subject Re: dynamic scoping in Forth in one line of code
Date 2026-08-28 18:12 -0700
Organization A noiseless patient Spider
Message-ID <87y0dplofj.fsf@nightsong.com> (permalink)
References <87bjamc5xh.fsf@debian>

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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.

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dynamic scoping in Forth in one line of code Kragen Javier Sitaker <kragen@canonical.org> - 2026-08-28 18:04 -0300
  Re: dynamic scoping in Forth in one line of code Paul Rubin <no.email@nospam.invalid> - 2026-08-28 18:12 -0700
    Re: dynamic scoping in Forth in one line of code Kragen Javier Sitaker <kragen@canonical.org> - 2026-08-29 10:50 -0300
  Re: dynamic scoping in Forth in one line of code albert@spenarnc.xs4all.nl - 2026-08-29 12:10 +0200
    Re: dynamic scoping in Forth in one line of code Kragen Javier Sitaker <kragen@canonical.org> - 2026-08-29 11:17 -0300
      Re: dynamic scoping in Forth in one line of code albert@spenarnc.xs4all.nl - 2026-08-30 12:49 +0200
        Re: dynamic scoping in Forth in one line of code Kragen Javier Sitaker <kragen@canonical.org> - 2026-09-01 20:38 -0300
          Re: dynamic scoping in Forth in one line of code Paul Rubin <no.email@nospam.invalid> - 2026-09-01 17:15 -0700
            coroutines (was Re: dynamic scoping in Forth in one line of code) Kragen Javier Sitaker <kragen@canonical.org> - 2026-09-03 20:38 -0300
              Re: coroutines (was Re: dynamic scoping in Forth in one line of code) dxf <dxforth@gmail.com> - 2026-09-04 15:24 +1000
                dynamic scoping in Forth in one line of code (was Re: coroutines) Kragen Javier Sitaker <kragen@canonical.org> - 2026-09-04 13:04 -0300
                Re: dynamic scoping in Forth in one line of code (was Re: coroutines) dxf <dxforth@gmail.com> - 2026-09-05 02:59 +1000

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