Here's a little puzzle. What is the third example doing?
state=: 3 2 2$ 1 1 2 1 1 1 2 2
(0;state;<a.={.a);: a=:' the quick brown fox jumps over the lazy dog'
--T-T-T-T-T-T-T-T-┐
│e│k│n│x│s│r│e│y│g│
L-+-+-+-+-+-+-+-+--
state=: 3 2 2$ 1 1 2 1 1 2 2 2
(0;state;<a.={.a);: a=:' the quick brown fox jumps over the lazy dog'
--T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-┐
│t│h│e│q│u│i│c│k│b│r│o│w│n│f│o│x│j│u│m│p│s│o│v│e│r│t│h│e│l│a│z│y│d│o│g│
L-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--
state=: 3 2 2$ 1 1 2 1 2 1 2 2
(0;state;<a.={.a);: a=:' the quick brown fox jumps over the lazy dog'
--T-T-T-T-T-T-┐
│e│k│n│x│s│e│g│
L-+-+-+-+-+-+--
state=: 3 2 2$ 1 1 2 1 2 2 2 2
(0;state;<a.={.a);: a=:' the quick brown fox jumps over the lazy dog'
--T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-┐
│t│e│q│i│k│b│o│n│f│x│j│m│s│o│e│t│e│l│z│d│g│
L-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--
Linda
-----Original Message-----
From: programming-boun...@jsoftware.com
[mailto:programming-boun...@jsoftware.com] On Behalf Of Linda Alvord
Sent: Thursday, March 08, 2012 9:30 PM
To: 'Programming forum'
Subject: Re: [Jprogramming] Sequential Machine
Roger, I'm not sure that this is what you had in mind.
a=:'a good way to start the day'
<;.1 a
---------T--------T---------T--┐
│a good w│ay to st│art the d│ay│
L--------+--------+---------+---
state=: 3 2 2$ 1 1 2 1 2 0 2 2 1 0 2 2
(0;state;<a.={.a);:a
---------T--------T---------T--┐
│a good w│ay to st│art the d│ay│
L--------+--------+---------+---
Linda
-----Original Message-----
From: programming-boun...@jsoftware.com
[mailto:programming-boun...@jsoftware.com] On Behalf Of Roger Hui
Sent: Monday, February 27, 2012 10:04 PM
To: Programming forum
Subject: Re: [Jprogramming] Sequential Machine
Yes, and your mission, should you decide to accept it, is to program this
function (let's say <;.1 y where ' '={.y) using the dyad ;: .
2012/2/27 Linda Alvord <lindaalv...@verizon.net>
> Maybe this will get me going on a sequential machine.
> <;.1 'a good way to start the day'
> ---------T--------T---------T--┐
> │a good w│ay to st│art the d│ay│
> L--------+--------+---------+---
> < ;.1 'a good time was had by all'
> --------------T----T------T---┐
> │a good time w│as h│ad by │all│
> L-------------+----+------+----
> < ;.2 'a good time was had by all'
> --------------------------T-┐
> │a good time was had by al│l│
> L-------------------------+--
> < ;.0 'a good time was had by all'
> ---------------------------┐
> │lla yb dah saw emit doog a│
> L---------------------------
> <;.2 'a good way to start the day'
> -----------T-----------------┐
> │a good way│ to start the day│
> L----------+------------------
> <;.2 'a good way to start the day '
> ---T-----T----T---T------T----T----┐
> │a │good │way │to │start │the │day │
> L--+-----+----+---+------+----+-----
>
>
> -----Original Message-----
> From: programming-boun...@jsoftware.com
> [mailto:programming-boun...@jsoftware.com] On Behalf Of Roger Hui
> Sent: Monday, February 27, 2012 1:22 PM
> To: Programming forum
> Subject: Re: [Jprogramming] Sequential Machine
>
> The one thing that drove home for me the efficacy of the dyad ;:, is
> that an implementation <;.1 y as a sequential machine was within a
> factor of 2 (something like that) of the primitive <;.1 y. I
> hand-coded the latter in C and devoted much effort to it.
>
>
>
> On Mon, Feb 27, 2012 at 9:49 AM, Raul Miller <rauldmil...@gmail.com>
> wrote:
>
> > I went through the wiki, with a text search on sequential machine,
> > looking for pages that might be of use here.
> >
> > The first page I examined (working up from the bottom on my list of
> > plausible candidates) was
> >
> >
> >
>
> http://www.jsoftware.com/jwiki/Guides/Language%20FAQ/J%20BNF?highlight
> =%28se
> quential%29%7C%28machine%29<http://www.jsoftware.com/jwiki/Guides/Lang
> uage%20FAQ/J%20BNF?highlight=%28se%0Aquential%29%7C%28machine%29>
> >
> > This led me to it's "See Also" link:
> > http://www.jsoftware.com/pipermail/chat/2007-November/000678.html
> >
> > And, I noticed there a statement by Oleg Kobchenko:
> >
> > J uses ... interpreter, which is a context-sensitive
> > bottom-up table-driven parser/executor:
> > http://www.jsoftware.com/help/dictionary/dicte.htm
> >
> > (which is obviosly not recursive-descent).
> >
> > And, from my point of view, this parser is obviously recursive descent.
> >
> > That said, the typical recursive descent parser is a left to right
> > parser. This is what the "LR" in various parser acronyms stands for.
> > J's parser is a right to left parser, so the parallel acronym would
> > be "RL". [Technically, "LR" means "Left to right, producing a
> > Rightmost derivation".]
> >
> > Secondly, most recursive descent parsers have "one token lookahead".
> > I have thought in the past that J uses "four token lookahead", but
> > this is not the case. J uses one token lookahead (only for
> > assignment). Instead, J uses four token "lookbehind".
> >
> > Conceptually speaking, the J parser pops four tokens off the stack.
> > But this is just a description of the internal state of the parser,
> > and does not impact its status as a recursive descent parser.
> >
> > A person might argue that "RL" and "LR" are not logically
> > equivalent, but I do not think that's relevant here. Ultimately,
> > the parser sees a sequence of tokens and from an algorithmic point
> > of view the meanings of "left" and "right" are implemented in
> > another module (the one that breaks the input stream into words).
> > But the lexer -- the module that breaks the input stream into words
> > -- is not considered when classifying the parser.
> >
> > Anyways, I just had to get that off of my chest.
> >
> > Some pages which look maybe interesting for learning about
> > sequential machines include (possibly in partially reversed order of
relevance):
> >
> > http://www.jsoftware.com/jwiki/Essays/Huffman%20Coding
> >
> > http://www.jsoftware.com/jwiki/Essays/Regex%20Lexer
> >
> > http://www.jsoftware.com/jwiki/Guides/Parsing
> >
> > http://www.jsoftware.com/jwiki/SequentialMachine
> >
> > http://www.jsoftware.com/jwiki/JWebServer/HttpParser
> >
> > And, of course, the Sequential Machine lab is probably a very good
> > resource to start with.
> >
> > --
> > Raul
> > --------------------------------------------------------------------
> > -- For information about J forums see
> > http://www.jsoftware.com/forums.htm
> >
> ----------------------------------------------------------------------
> 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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