Viktor Cerovski wrote:
> I should tell you that there is a tacit solution to your
> problem
Viktor, that was a neat post, and it gives me some insight to "monads" (in the
Haskell sense), which I've been struggling with. Thank you.
But just so no one is led astray by your terrible heresies, let me denounce
them a bit. At the end I'll make it up by presenting an even more insidious
perversion from the vaults.
First, you're right that v isn't tacit (functional) in the J sense. Or, it
is, at any given moment of time, but not in motion as you've shown it. What is
"a moment in time" and "in motion"? A "moment" is a given, specific
definition, and "in motion" means "throughout the course of multiple
definitions". Because, of course, v is defined in terms of TTT, which you keep
redefining. The fact that v can give outputs for the same inputs every time
you redefine it should be no more surprising than this:
f =: +:
f 12
24
f =: *:
f 12 NB. Oh noes! Same line, different result!!11one
144
Put another way, Ian indicated his CAL has no control over TT (which your TTT
mimics). He doesn't define (or re-define) it; CAL just receives a signal and
begins calculating on the current value stored there. So how do you arrange
for your tacit verb to keep up with this externally-changing value? Your
method won't work.
But here is a perversion which will:
load'jmf'
createjmf_jmf_ 4000;~jpath'~temp\TT.jmf'
map_jmf_ 'TT';jpath'~temp\TT.jmf'
TT =: i. 4 4
TTT =: TT #@:[ ] NB. Length of TT, as a orthodox, mundane NVV
tacit verb
TTT ''
4
TT =: i. 12 4 NB. TT can change behind the scenes...
TTT '' NB. and TTT will keep up
12
TT =: i. 125 4 NB. Fun!
TTT ''
124
TT =: i. 126 4 NB. Awww :(
|allocation error
| TT =:i.126 4
Just don't let your children see it.
-Dan
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