That's great. Thank you.
For some reason I was expecting the use of an explicit adverb to still
be called by name (and thus break the pure, functional, point free
concept). My assumption was wrong:
op_cmp =: (([: (([: (*@-~)/ pV&{::) op_push ]) 2 popn))
op_cmp
[: (([: *@-~/ 2&({::)) op_push ]) [: ([ ((0 {:: ]) ; (1 {:: ]) ; ((2
{:: ]) , 2 {:: [) ; 3 {:: ]) op_pop)^:2 ]
It may not be a surprise to most but I was very happy to see that the
result of an adverb on a tacit verb is a new tacit verb
Simplified:
copy=: (1 : ',^:(<:m) ]')
sum4_copies =: [: +/ [: 4 copy ]
I would have thought sum4_copies would have been something like
[: +/ [: 4 copy ]
or
[: +/ [: (1 : ',^:(<:m) ]') ]
not:
[: +/ [: (,^:3 ]) ]
If someone has a dictionary or other doc reference handy that explains
this I would be grateful to deepen my understanding, although it seems
pretty straightforward
On Thu, Nov 12, 2015 at 8:44 PM, 'Pascal Jasmin' via Programming
<[email protected]> wrote:
>>'pC pIP pV pS' =: i. 4
>
>
> notice that all uses were accessors, so this might have saved some parens.
>
>
> (i.@# 4 : '(y) =: x {:: ] label_. y' each ] ) ;:
> 'pC pIP pV pS'
>
> pC
> 0 {:: ]
>
>
> trying to make that a popn
>
> popn=: 1 : '[: ([ ( (pC{::]) ; (pIP{::]) ; ((pV{::]) , (pV{::[)) ; (pS{::]))
> op_pop)^:m ]'
>
> ...and done.
>
>
> 3 popn
> [: ([ ((pC {:: ]) ; (pIP {:: ]) ; ((pV {:: ]) , pV {:: [) ; pS {:: ])
> op_pop)^:3 ]
>
> ----- Original Message -----
> From: Joe Bogner <[email protected]>
> To: [email protected]
> Cc:
> Sent: Thursday, November 12, 2015 8:13 PM
> Subject: Re: [Jprogramming] essay: toy byte code interpreter
>
> Thanks for the feedback. Your utm is impressive and helped me me get
> into the style of small bits of tacit composed together and then
> fixed. It was a joy to work with at times and frustrating at others. I
> think it's worth writing an essay to share tips/tricks for larger
> tacit programs. I may take a crack at it.
>
> Thoughts:
>
> 1. Tracing execution was somewhat challenging. I finally got the knack
> of it with variations of the following:
>
> (smoutput bind [) ] ])
>
> Debug could useful too. I didn't use it as much as I could have when I
> was writing this. I have only recently started using debug (really
> only twice - to learn more about the internals of plot and the utm).
> Need to keep it top of mind for the future and reach for it more often
>
> 2. Think about the data structure that will be threaded through the
> calls up front. I did a reasonable job planning out and using nouns to
> describe the various offsets:
>
> 'pC pIP pV pS' =: i. 4
>
> op_push =: (pC {:: ]) ; (pIP {:: ]) ; '' ; (<@: ((0{[) , getStack))
>
> This became problematic because I thought I'd be clever at points and
> use 2{. to skip and then when I inserted something in the beginning it
> broke alot of things. For example, I didn't have pC (the code) as part
> of the structure until I implemented jumps, so I had to go back and
> rework a few statements (surprisingly tedious) to make it work. Things
> would break and it was somewhat troublesome to step through
>
> 3. Fix (f.) at the end, so you can still use the named versions in
> debugging or test code
>
> 4. Use more test cases (need to do more of this). Ideally each tacit
> expression has a test case accompanied with it so when something goes
> wrong you can go back and check the work.
>
> Something like this:
> http://www.jsoftware.com/pipermail/programming/2014-July/038316.html
>
>
> 5. Too many parentheses. Is there a way to eliminate unnecessary
> parens automatically? I find myself throwing them in just in case
>
> 6. Use more helpers to reduce visual clutter - I'm sure this will come
> with practice
>
> 7. When to amend vs reconstruct. I think I have many opportunities to
> use an item amend instead of rebuilding the struct with a single new
> value
>
> op_push =: (pC {:: ]) ; (pIP {:: ]) ; '' ; (<@: ((0{[) , getStack))
>
> That can be written with an item amend and might be more clear
>
>
>
> Aside from all that, it was really quite fun and I was impressed by
> what can be accomplished in such a terse, pure manner. The style of
> composing it can still make it very readable..
>
> One of the cooler things I realized was how I could pop from the stack
> twice (or as many times as needed) with this expression:
>
> pop2=: [: ([ ( (pC{::]) ; (pIP{::]) ; ((pV{::]) , (pV{::[)) ; (pS{::])
> ) op_pop)^:2 ]
>
> which repeatedly pops and overwrites the 2nd item in the struct with a
> running list of the popped values. I spent about 10 minutes trying to
> make that a popn that let it take an argument of the times to pop but
> then things started to get tricky when mixing valences. Anyhow, good
> stuff!
>
> Thanks again
> Joe
>
> On Thu, Nov 12, 2015 at 7:34 PM, Jose Mario Quintana
> <[email protected]> wrote:
>> 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
>>> >> ----------------------------------------------------------------------
>>> >> For information about J forums see http://www.jsoftware.com/forums.htm
>
>>> >
>>> >> ----------------------------------------------------------------------
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>>> > ----------------------------------------------------------------------
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>>> ----------------------------------------------------------------------
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>>>
>> ----------------------------------------------------------------------
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