Thanks Ric, that helps.
You are right. I haven't addressed the issue of the (DDD) fork, where
the presence of a left argument establishes that the outer two verbs are
dyadic. In S this would be: (([)*)%([)- . I agree that this contains
extra parentheses. However, it does follow the right to left rule.The
expression (([)*) is evaluated before the % because of its parentheses. In
S, a dyadic verb is always identified by a noun or a parentheses on its
immediate left - as is true in non-tacit J programming. This is why an extra
tacit form is not needed.
7 (* % -) 3 2 does not follow the right to left rule because the * is
not enclosed in parentheses, but is used before the % to its right.
Don
___________________________________________________________________________________
> I think what Bill was trying to point out is that the valence of a verb
> does not depend on its position in the verb train, but on its context.
>
> Here is a tacit train of 3 verbs:
> (* % -)
> Currently we (and J) have no idea whether * and - will be monadic or
> dyadic verbs. We don't know until we give the sentence nouns.
> In the following sentence * and - are monadic because only a right
> argument is supplied:
> (* % -) 3 2 4
> _0.333333 _0.5 _0.25
> Here they are dyadic because both a left and right argument is supplied:
> 7 (* % -) 3 2 4
> 5.25 2.8 9.33333
>
> % is dyadic in both cases because when it gets around to being executed it
> has both left and right noun arguments
> (the results of * 3 2 4 or 7 * 3 2 4 and - 3 2 4 or 7 - 3 2 4).
>
> I think perhaps your first statement is also incorrect or at least
> imprecise - Tacit form does not abandon right to left parsing, it just
> changes the order of execution in the same way as parentheses can in
> explicit form.
>
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