Hi Raul,
I think our differences may stem from looking at different sides of the
elephant. You see the trunk, I see the legs - or vice-versa. Both views may
be reality, just different views of reality.
You state:
"I do not understand your continued emphasis on monadic verbs in this
discussion."
This is how I view it. I will take a very simple explicit J expression
with only dyadic verbs, constants and a right argument:
3+2-7*5^y
You can break this up as follows:
3+ 2- 7* 5^ y
M M M M
I have placed an M under each constant followed by dyadic verb, because
together they are the equivalent of a monadic verb. Tacit J does exactly
this with the expressions: 3&+, 2&-, 7&*, and 5&^. That is why I am
looking at any arithmetic or language with the right to left rule as a
stream of monadic verb expressions. In the revised tacit J that I am
proposing, I am also dealing with a right to left rule; so I also see a
stream of monadic verb expressions in my tacit J. If I turn the explicit J
into revised tacit programming, I have:
Verb=: 3+ 2- 7* 5^
M M M M
So my new verb is a stream of monadic phrases.
That's the trunk I'm looking at.
You state
"Your assertion that J tells whether a verb is monadic by its
position in the stream is just plain wrong.
It is perfectly possible to have a monadic verb in any of the even positions
provided there is a cap to its left. It is even possible to have a cap with
a verb which may be used in either a monadic or dyadic context, and the cap
forces use of the monadic form."
Your view says: "The cap is a useful facility because it enables me to
to place a monadic verb where a dyadic verb would be expected
otherwise.
My view says "There is a problem because tacit J is expecting a
dyadic verb where I want to put a monadic verb. The cap is a patch
that solves this problem.
I believe that we are both right.
You state:
"There is a clear and simple sense in which the train follows the right to
left rule. The first three verbs from the right are executed with reference
to the arguments of the train, then that result is the right argument of the
next verb in the train. So we have for the odd number of verbs case
v v (v v (v v (v v v)))
where each parenthesis reaches out to the arguments of the call of the train
and each pair of verbs and its right parenthesized group is treated as a
fork.
For the even number of verbs case we have a hook
v (v v (v v (v v v)))"
I agree, except that it isn't proper right to left, because you can't
use fork functions to write it as:
F(G(H(K(y))))
The problem comes when you want to add an extra monadic verb
on the way:
v (v v (v v v(v v v)))
Without the cap, the system will wrongly interpret it as:
v v (v v (v v(v v v)))
So I see the cap as needed to patch a problem.
You state:
"I cannot see how your (M1)DM2 expression as the definition of a train would
work if all of the verbs are dyadic."
In the definition above: Verb=: 3+ 2- 7* 5^ there is nothing
but
dyadic verbs. The constants could, of course be replaced by a named noun or
a noun phrase:
Verb =: a+ (n^5)- 7* 5^
However since we should try to avoid global variables, we might also use
the exression: x+ (n^y)- 7* 5^ y This would convert in revised tacit J
to
a dyadic verb:
verb=: ([)+ (n^)- 7* 5^
The ([) is perhaps a patch in my tacit programming, because the right to
left rule - all basic monadic verb expressions - needs a parenthesis to the
left
of a verb to tell it is dyadic since the noun has been taken out.
Don
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