Joe,
We currently are experimenting with a style variant that further simplifies
writing tacit code using a current version of an Jx interpreter. One of
the first verbs tested was the Universal Turing Machine that you referred
in the Wiki. I was thinking about rewriting your Byte Code Interpreter
tacitly this way but you beat me :) The Jx interpreter is still evolving
but we might release another version in the future.
Even if a Jx interpreter is employed to produce a tacit verb the latter may
run on an official interpreter. A utm running this way and the script that
produced it is shown below.
I might still try to rewrite in this manner your Byte Code Interpreter; in
the mean time, your tacit version is already in my collection. Thanks for
sharing it.
JVERSION
Installer: j602a_win.exe
Engine: j803/2014-10-19-11:11:11
Library: 6.02.023
". noun define -. CRLF NB. Fixed tacit universal Turing machine
code...
utm=.
(((":@:(]&:>)@:(6&({::)) ,: (":@:] 9&({::))) ,. ':'"_) ,. 2&({::)
>@:(((48"_ + ]) { a."_)@:[ ; (] $ ' '"_) , '^'"_) 3&({::))@:(-^:_@
:1:^:(-.@:(_1"_ = 1&({::))))@:((<@:(1 + 9&({::)) (,9)} ])@:(<@:(3&
({::) + 8&({::)) (,3)} ])@:(<@:((0: 0&({::)@:]`(<@:(1&({::))@:])`(
2&({::)@:])} ])@:(7 3 2&{)) (,2)} ])@:(<"0@:(6&({::) (<@:[ { ]) 0&
({::)) 7 8 1} ])@:([ 1!:2&2@:([ 11!:0@:('msgs'"_))@:(((":@:(]&:>)@
:(6&({::)) ,: (":@:] 9&({::))) ,. ':'"_) ,. 2&({::) >@:(((48"_ + ]
) { a."_)@:[ ; (] $ ' '"_) , '^'"_) 3&({::))^:(0 = 4&({::) | 9&({:
:)))@:(<@:(1&({::) ; 3&({::) { 2&({::)) (,6)} ])@:((<@:0: (,3)} ])
^:(0 = 1 + 3&({::)))@:((<@:(2&({::) , 5&({::)) (,2)} ])^:(3&({::)
= #@:(2&({::))))@:((<@:(5&({::) , 2&({::)) (,2)} ])^:(_1 = 3&({::)
))^:(-.@:(_1"_ = 1&({::)))^:_)@:(<@:((({. , ({: % 3:) , 3:)@:$ $ ,
)@:(}."1)@:(".;._2)@:(0&({::))) (,0)} ])@:(<@:0: 5 9} ])@:(<@:(''
, 2&({::)) (,2)} ])@:('B M PRINT MOVE C'&(] , ;:@:[))@:(,~)
)
NB. A classic program.
NB. 0 Tape Symbol Scan
NB. S p m g
QS=. (noun define) ; 0 NB. Reading the transition table
and setting the state
0 24 1 1
1 53 1 2
2 60 1 3
3 60 1 4
4 63 1 5
5 _16 1 6
6 71 1 7
7 63 1 8
8 66 1 9
9 60 1 10
10 52 1 11
11 _15 1 _1
)
TPF=. 0 ; 0 ; 1 NB. Setting the tape, its pointer
and the display frequency
TPF utm QS NB. Runing a classic program
0 0:0
0 :^
1 0:H0
1 : ^
2 0:He0
2 : ^
3 0:Hel0
3 : ^
4 0:Hell0
4 : ^
5 0:Hello0
5 : ^
6 0:Hello 0
6 : ^
7 0:Hello w0
7 : ^
8 0:Hello wo0
8 : ^
9 0:Hello wor0
9 : ^
10 0:Hello worl0
10 : ^
11 0:Hello world0
11 : ^
11 0:Hello world!
12 : ^
This is the Jx script that produced utm (using a pre-loaded tool set):
NB. Universal Tacit Turing Machine
NB. utm (dyadic verb)
Set [tp ; LOCAL=. [tp
NB. L...
B - Blank Defaults
M - State and Tape Symbol Holder
PRINT - Printing Symbol
MOVE - Tape Head Moving Instruction
C - Step Counter
)
NB. Y...
Q - Instruction Table
S - Turing Machine State
NB. X...
T - Data Tape
P - Head Position Pointer
F - Displaying Frequency
)
rt=. ((({. , ({: % 3:) , 3:) o $) $ ,) o (}."1) o (". ;. _2)
NB. Reshape transition table as a 3D array (state-symbol-action)
DisplayTape=. > o (((48 c + ]) { a.c)x ; ((] $ ' 'c) , '^'c))
NB. Display Tape (verb) (e.g., T DisplayTape P)
display=. ((((": o (]&:>) o M) ,: (":y C)) ,. ':'c ),.(T DisplayTape P))
NB. Displaying state, symbol, tape / step and pointer
NB. utm (not in-place)...
execute=. [tv
(T h (B , T)) t (_1 = P) NB. Adjusting the tape's left hand
side if
NB. necessary (using lazy evaluation)
(T h ( T , B)) t (P = # o T ) NB. Appending
(P h 0:) t (0 = 1 + P) NB. Adjusting the pointer if
necessary (lazy version)
M h ( S ; (P { T) ) NB. Updating the state and reading
the tape symbol
[ (screen o display) t (0 = F | C ) NB. Displaying intermediate cycles
(PRINT MOVE S) h (<"0 o (M bi Q) ) NB. Setting the actions
T h ( amend o ((PRINT P T)ff) ) NB. Printing symbol on tape
P h ( P + MOVE ) NB. Moving the pointer (if necessary)
C h ( 1 + C ) NB. Increasing the counter
)
halt=. _1 c = S NB. Halting when the current state is
_1
InfiniteRegress=. (-^:_) o 1: t (-. o halt)
NB. Alternatively:
NB. ][ screen o ('A trivial infinite regress event.'c) t (-. o halt)
utm=. [tv f. NB. Fixing the tacitly defined
TuringMachine
,~ NB. Dyadic form (e.g., TPF
TuringMachine QS )
LOCAL ln NB. Making room for local boxes (B M
PRINT MOVE C)
T h ( '' , T ) NB. Forcing the tape to be a list
(B C) h (< o 0:) NB. Setting local B (empty defaults)
and counter as 0
Q h (rt o Q) NB. Reshaping the transition table
execute whilst (-. o halt) NB. Executing instructions the Turing
machine program
InfiniteRegress NB. Detecting an infinite regress
event
display
)
utm wrap
On Thu, Nov 12, 2015 at 3:59 PM, Joe Bogner <[email protected]> wrote:
> I've added a pure functional tacit version:
>
> http://code.jsoftware.com/wiki/User:Joe_Bogner/ByteCodeInterpreter#Tacit_Version
>
> Here's a silly proof:
>
> NB. wrapped at 50 characters so line fees shouldn't cause issues
>
> run =: ; <;._2 (0 : 0)
> (0&{ , >:@:(1 {:: ]) ; 2&}.)@:(((1 {:: ]) { [) ((0
> {:: ]) ; (1 {:: ]) ; {.@:(3 {:: ]) ; }.@:(3 {:: ]
> ))`((0 {:: ]) ; (1 {:: ]) ; '' ; <@:((0 { [) , 3 {
> :: ]))`]`(+/@:}.@:[ ((0 {:: ]) ; (1 {:: ]) ; '' ;
> <@:((0 { [) , 3 {:: ])) ])`([: (([: *@-~/ 2&({::))
> ((0 {:: ]) ; (1 {:: ]) ; '' ; <@:((0 { [) , 3 {::
> ])) ]) [: ([ ((0 {:: ]) ; (1 {:: ]) ; ((2 {:: ])
> , 2 {:: [) ; 3 {:: ]) (0 {:: ]) ; (1 {:: ]) ; {.@:
> (3 {:: ]) ; }.@:(3 {:: ]))^:2 ])`((0 {:: ]) ; _ ;
> '' ; 3 {:: ])`]`]`([ (<@:(2&{."1@:(0 {:: ]) i. 6 ,
> 1 {:: [) 1} ])^:(1 = 2 {:: ]) (0 {:: ]) ; (1 {::
> ]) ; {.@:(3 {:: ]) ; }.@:(3 {:: ]))`(([: (0 0 $ 1!
> :2&2)@({"_)&(<;._1 '|exiting|greater than') 1&({::
> )@:[) ] ])@.(0 {:: [) ])^:(1 = (1 {:: ]) < <:@:#@:
> [)^:_ (] ;&(0;'';''))
> )
>
>
> This program will add 6 and 5 together, pop the result into the
> current value register and then exit
>
> (; run) (128!:2) (3 6 5),(0 0 0),:(9 0 0)
>
>
> The resulting frame is the program, instruction pointer, current
> value, and stack (empty)
>
>
> +-----+-+--++
> |3 6 5|2|11||
> |0 0 0| | ||
> |9 0 0| | ||
> +-----+-+--++
>
>
> Further demonstration of the power of J's tacit engine. A toy
> interpreter like this shows we can write code in an explicit
> mini-language and have it run tacitly. I'm not sure of practical uses
> and I'm not advocating using this for anything serious. J's tacit
> engine acts as a virtual machine for the byte code.
>
> On Tue, Nov 10, 2015 at 4:57 PM, 'Pascal Jasmin' via Programming
> <[email protected]> wrote:
> > J is arguably already bytecode... ascii. And fairly terse.
> >
> > an extension to this:
> >
> http://code.jsoftware.com/wiki/User:PascalJasmin/JON_assignment_free_pure_functional_DSL
> >
> > would be to use instead of an assignment system, an object that is a
> combination of queue, stack and dictionary that stores and retrieves
> results.
> >
> >
> >
> >
> > ----- Original Message -----
> > From: Joe Bogner <[email protected]>
> > To: [email protected]
> > Cc:
> > Sent: Tuesday, November 10, 2015 4:49 PM
> > Subject: Re: [Jprogramming] essay: toy byte code interpreter
> >
> > Thanks. I don't have any application of it yet other than demystifying
> > the concept of a bytecode interpretation. It does open up some
> > interesting options of doing cool stuff with stacks in J.
> >
> > I am also thinking it would be a neat hack to implement a subset of J
> > in J using interpreted bytecode. I would then probably write an
> > interpreter of the bytecode in another language too for fun.
> >
> >
> >
> >
> >
> > On Tue, Nov 10, 2015 at 4:33 PM, 'Pascal Jasmin' via Programming
> > <[email protected]> wrote:
> >> Its cool.
> >>
> >> is your interest to do cool stuff with stacks in J, make a stack
> language or interpret bytecode?
> >>
> >>
> >> If its the first, I have many suggestions.
> >>
> >>
> >> ________________________________
> >> From: Joe Bogner <[email protected]>
> >> To: [email protected]
> >> Sent: Tuesday, November 10, 2015 4:07 PM
> >> Subject: [Jprogramming] essay: toy byte code interpreter
> >>
> >>
> >> I wrote this over lunch today and was pleased to see how simple it
> >> was. I'm posting here for those who don't follow Recent Changes.
> >> Feedback welcome
> >>
> >> http://code.jsoftware.com/wiki/User:Joe_Bogner/ByteCodeInterpreter
> >>
> >> I'd be interested in any speedups to the timing test that still permit
> >> jumps. It's fine as-is for a toy though
> >> ----------------------------------------------------------------------
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> >
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