[Jprogramming] A phrase for amendment

[Sherlock, Ric]

Thanks Dan that's fantastic!
Especially the step-by-step building. Would be worth putting up on the Wiki as a guide?

If you don't see yourself getting around to it, let me know and I'd be happy to do it as pay back for your time.

Ric

> -----Original Message-----
> From: programming-bounces at jsoftware.com [mailto:programming-
> bounces at jsoftware.com] On Behalf Of Dan Bron
> Sent: Wednesday, 24 November 2010 13:15
> To: 'Programming forum'
> Subject: Re: [Jprogramming] A phrase for amendment
> 
> Ric wrote:
> >  I would probably just define the verb
> >  directly including the monad:
> 
> If I don't know how to approach a problem tacitly, I'll define it explicitly
> first:
> 
> 	1 :  'u@:{`[`]}'
> 
> This has the benefit of not baking in an argument (hence, reusability), but
> it also will help me work my way towards a tacit solution, as we'll see.
> 
> >  if you have a tips on how you
> >  went about composing your adverb
> >  I'd be interested.
> 
> Sure.  Come on over to the dark side.
> 
> The first step towards building a tacit adverb is knowing exactly what you
> want as a result.  In this case, we want  u@{`[`]} .  If you don't have a
> clear picture of what you want, building the solution explicitly first can
> help, as I said.
> 
> Given a clear goal, and a few techniques, building a tacit adverb is
> actually a fairly mechanical process (hmm, maybe I can make an 11 : '...'  )
> .  Some techniques are:
> 
> 	-  a tacit adverb is an adverb train  - that is,
> 	   it is composed solely of adverbs.
> 
> 	-  normally those adverbs are either primitives,
> 	   like / or bound conjunctions like (@{)
> 
> 	-  the argument comes in from the left, so you
> 	   start modifying it there.
> 
> 	-  for verb arguments, normally you either want
> 	   to compose them with other verbs, or you want
> 	   to produce a train.
> 
> 		-  adverbs which produce composed verbs are
> 		   easy to write, if you want (u conj
> 		   something) you write (conj something),
> 		   and if you want (something conj u) you
> 		   write (something conj).
> 
> 		   That's the beauty of tacit code - the
> 		   missing arguments are so "obvious",
> 		   it's almost like writing "fill
> 		   in the _____s."
> 
> 		-  adverbs which produce verb trains aren't
> 		   quite as clean, but they're still easy
> 		   and mechanical, and leverage the rule
> 		   above and the utility (`:6).  By definition,
> 		   (f`g`h`i`j) `:6  produces (f g h i j) so
> 		   if you want to produce that train given f,
> 		   then you just write (`g)(`h)(`i)(`j)(`k)(`:6) .
> 		   Similarly, if you wanted to produce
> 		   (v0 f v1) given f, you'd write (v0`)(`v1)(`:6) .
> 
> 	-  when in doubt, parenthesize.
> 
> 	-  work iteratively, in small pieces:
> 
> 		-  Given f, I want g f"2&.>/@:(,&<) h .
> 
> 		-  OK, let me write an adverb that
> 		   produces f"2 given f :  ("2)
> 
> 		-  OK, let me write an adverb that
> 		   produces  f1&.> given f1=.f"2 :  (&.>)
> 
> 		-  OK, let me write an adverb that produces
> 		   f2/ given  f2=.f1&.> :  /
> 
> 		-  OK, let me write an adverb that produces
> 		   f3@:(,&<) given  f3=.f2/ :  (@:(,&<))
> 		   (or in two steps:  (@:,) (,&<)  )
> 
> 		-  OK, now I need a train g f4 h given
> 		   f4=. f3@:(,&<)  :
> 
> 			-  g will come to the left of f4 in the
> 			   train, so:  (g`)
> 
> 			-  h will come to the right of g and f4 in
> 			   the train, so:  (`h)
> 
> 			-  OK, now I've got my gerund, so let me
> 			   evoke it as a train:  (`:6)
> 
> 		- OK, a tacit adverb is just a train of adverbs,
> 		  so let me collect all my pieces in order:
> 
> 		  adv =. ("2) (&.>) / (@:(,&<)) (g`) (`h) (`:6)
> 
> 		  f adv
> 		g f"2&.>/@:(,&<) h
> 
> See?  Quite mechanical.  Now, it can get more advanced than this,
> particularly through the manipulation of atomic representations.
> 
> I won't get into that here, except to note that (`'')  is an anonymous tacit
> adverb that will produce the atomic rep of its verb argument (well, the
> ravel of the a.r. of its verb argument), and once you have that, you can use
> normal tacit verbs to manipulate it to taste, then evoke it later with 5!:0
> .  In some sense,  (`'')  is analogous to  ("_)  .
> 
> If you want to get really advanced and fancy:
> 
> 	-  recognize that *everything* has an atomic
> 	   representation (heh:  Ambrus once found an
> 	   atomic rep that was _its own atomic rep_).
> 
> 	-  get familiar with the definition of  @.
> 	   having a boxed noun RHA.
> 
> -Dan
> 
> 
> 
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