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From: minforth@gmx.net (minforth)
Newsgroups: comp.lang.forth
Subject: Re: Operator =?UTF-8?B?b3ZlcmxvYWRpbmc/?=
Date: Tue, 30 Jul 2024 18:55:55 +0000
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On Tue, 30 Jul 2024 15:16:28 +0000, Stephen Pelc wrote:
> The standard suggests/specifies that operators such as TO behave as if
> they parse. Ignore that for the moment and define
>
> variable operator
>
> : to  1 operator !  ;  immediate
>
> A child of VALUE is probably an immediate word that inspects OPERATOR
> and compiles the fetch action if 0 or the store action if 1. This scheme
> can
> be extended to support a wide range of operators, such as +TO INCR DECR
> and so on. MPE has used this scheme for several decades with no tech
> support issues. If you really want to to be fussy and avoid the use of
> the
> "as if" rule for parsing, you can do something like (untested) the below
> for TO. But why bother?
>
> : to
>   1 operator !  ' execute
> ;  immediate

Thank you. So instead of wasting time on parsing during compilation- or
interpretation time, the runtime action of an xVALUE (even when
compiled)
involves to walk a type-specific operator chain (a large CASE construct
in VFX). This makes them slower when compiled, but why not.