My apologies. You are right. I meant to refer to a hook, not a fork and I
should have been using @: If I could use { } as brackets to send me from
tacit programming to a J sentence, I think that u @: v would be the
same as { u v } , which was my point.
If we use F to represent +/ , G to represent # and H1 and H2 to represent
% . F and G are monadic as F(x) and G(x) and H is normally dyadic as H
(x,y). In tacit programming we are replacing H1 [ F(x), G(x) ] by [
H2 (F, G) ] (x) In which case H1 and H2 are not the same kind of
mathematical function - are they?
Don
----- Original Message -----
From: "Don Guinn" <[email protected]>
To: "General forum" <[email protected]>
Sent: Saturday, March 14, 2009 7:36 PM
Subject: Re: [Jgeneral] Teaching
>I haven't been following this thread too closely, so I hope I am not
> repeating something already covered.
>
> "@" and "@." are conjunctions and a fork is three verbs together. So that
> is
> not a fork. And I think that you mean "@:", not "@." . You can already
> mark
> the beginning and end of a tacit segment of a sentence using parens. As in
> the example I seem to remember appearing earlier in this thread (+/%#)1 4
> 5
> 6 8
> will compute the average. The parens show that the expression within them
> is
> tacit as no arguments are within the parens.
>
> Remember in algebra class where the teacher rewrote
> F(x)+G(x)
> to
> (F+G)(x)
> ?
> That's a fork.
>
> On Sat, Mar 14, 2009 at 5:00 PM, Don Watson <[email protected]> wrote:
>
>> There seems to be a need for J sentences within tacit programming
>> anyway. For example, the primitives "@" and "@." seem to be saying: "I
>> want
>> to follow one verb with another. Since I'm in tacit programming, they
>> will
>> be treated as a fork. I want you to treat these two verbs as though they
>> were in a J sentence instead." So, in a sense, we are already trying to
>> get
>> out of tacit programming. Why not do it properly and have a lot more
>> freedom,
>> capability and understandability?
>>
>> For the moment, I should stick to ASCII. It is less confusing in this
>> discussion. Since there are no brackets left, I am going to have to use
>> "F."
>> as a left bracket and "F:" as a right bracket.
>>
>> "F:" says: "The script to my left is a J sentence. Pass the result so far
>> as
>> the right argument of that J sentence."
>>
>> "F." says: "The script to my left is tacit programming. Pass the result
>> so
>> far as the right argument of that tacit programming."
>>
>> The Standard Deviation verb is now:
>>
>> SD =. F. %:(%N) * +/ *: F: ( ] - (+/ % F. N =. F: #))
>>
>> Obviously it would look a lot better if the "{" and "}" could be
>> recovered as brackets and used instead of "F." and "F:".
>>
>> SD =. { %:(%N) * +/ *: } ( ] - (+/ % { N =. } #))
>>
>> This I can understand.
>>
>>
>> Don
>>
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
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