[racket-users] NEED || WebSphere Commerce Architect || San Francisco, CA
Hi Partners, This is Aanchal from Technology resource Group. Below is the job description and requirements for your perusal and please contact me if having any questions or concerns. *Role: WebSphere Commerce Architect* *Location: San Francisco, CA* *Duration: 6 Months (Extension possible) and 2 Week trip to china (Paid) during the assignment* *Interview Mode: Telephonic Interview followed by Skype* *Job Description:* *We need a contractor with Websphere Commerce platform experience for 6 month assignment. 2 weeks trip to China (paid) during this assignment.* *It is a Web sphere Commerce platform, like Hybris, or ATG. * *And it has to be an Architect, a person who understand how this platform works together.* Thanks and Regards, Aanchal Arora | Technical Recruiter Technology Resource Group Inc. 3736 Hillsdale Court Santa Clara, CA 95051 Office:408-709-1760 Ext : 812 | Direct: 408-826-8378 Gtalk/YM: http://www.tresourceinc.com/ aanchalarora825 | Fax: 408-884-2409 aanc...@tresourceinc.com | www.tresourceinc.com -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
On Tuesday, June 23, 2015 at 8:30:32 AM UTC-4, Matthew Flatt wrote: Providing #f as the third argument to `local-expand` means that (+ i j) is expanded only as far as exposing the primitive function-call form, also known as `#%plain-app`: (#%plain-app + i j) When `i` is encountered later, there's no binding in the compile-time environment, because the internal-definition context has been discarded as the `my-def-stx` macro returned. Probably you want to replace the `#f` with `null` (which means expand without stopping). Got it - this makes sense, thanks. Another possibility is to expand to a `letrec-syntaxes+values` form to bind `i` and `j`. This is actually what I'm trying to avoid - see the earlier note on why I need a solution that won't leave behind empty (let-values () ...) forms (or any other Racket-specific forms) in the output syntax. At Tue, 23 Jun 2015 02:13:19 -0400, Thomas Dickerson wrote: I seem to be missing some key ingredient here. The following really simply test-case, using let-syntaxes, works as expected: (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) #'(let-syntaxes ([(id ...) rhs]) expr)]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) Trying the same thing, but with this: (require (for-syntax syntax/context)) (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) (let* ([intdef (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (syntax-list #'(id ...)) (local-transformer-expand #'rhs 'expression null) intdef) (internal-definition-context-seal intdef) (local-expand #'expr ctx #f intdef))]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) instead, gives me i: undefined; cannot reference an identifier before its definition. Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Mon, Jun 22, 2015 at 11:39 PM, Matthew Flatt mfl...@cs.utah.edu wrote: Probably you don't want to work with namespaces, which are intended more for run-time reflection. For an example of turning internal definitions into 'letrec-syntaxes+values', try the implementation of 'racket/block'. On Jun 23, 2015, at 10:06 AM, Thomas Dickerson thomas_dicker...@brown.edu wrote: Update / addendum: I was also able to fairly trivially extend Alex's code using let-syntax to have the more hygienic behavior for where Accum is/is-not visible, but let-syntax ends up leaving an additional layer of empty (let-values() ...) behind. The documentation for let-syntax makes the following claim - The evaluation of each trans-expr is parameterized to set current-namespace to a namespace that shares bindings and variables with the namespace being used to expand the let-syntax form, except that its base phase is one greater. which seems very much related to what I'd like to accomplish (and Shriram's suggestion that I mentioned in the original post); however, I see no evidence of this actually taking place in the Racket source-code, it just appears to desugar, with very few bells and whistles, to letrec-syntaxes+values which evidently is implemented in the C code. Digging into syntax-parameterize shows that, unsurprisingly, this is also how syntax-parameterize gets desugared, with a few more bells and whistles. So I guess at this point the remainder of my question boils down to this: can someone offer any insight into the process of turning macros which are introduced by let-syntax or equivalent into macros which are introduced implicitly by an internal-definition-context argument to local-expand, or by explicit namespace manipulation as hinted at in the let-syntax documentation (but which I can't turn up anywhere). On Monday, June 22, 2015 at 5:35:50 PM UTC-4, Thomas Dickerson wrote: Thanks for the effort that went into figuring that out! A couple first thoughts on the implementation: To first order, this is exactly what I want to be able to do (and it elegantly avoids local-expand by reasoning about expansion order); however, as a general pattern, it's a bit unhygienic in that Accum is now in the global namespace, which precludes using it as a child macro for other constructs, and prevents specific instantiations of Loop from requesting a different name for Accum to cooperate in nested loops. I also noticed that (syntax-parameterize) isn't totally transparent in the expanded syntax - it leaves a bunch of empty (let-values () ...) behind, which is fine for
Re: [racket-users] Closing big-bang windows
I, for one, thought the idea of “OS” reads and writes from Get Bonus was a neat abstraction, even if it is more or less just functional reads and writes to a giant hash table. Obviously that’s more complicated than would be appropriate for big-bang, but I thought I’d bring it up anyway. On Jun 23, 2015, at 8:30 AM, Matthias Felleisen matth...@ccs.neu.edu wrote: I have for years hoped to find time to think about 'distributing state' over handlers in big-bang because I am perfectly aware of the scaling up limitations. Your hashtable idea might be worth exploring. Tony and I are also considering his actor system as a source of ideas. This may also give us a handle at a special-purpose gc as Tony noted yesterday. But now I am way off stuff I have done, and I don't like to discuss things that I might do so forgive me for this much and I'll stop now -- Matthias -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] try a new macro expander
On 06/22/2015 08:25 AM, Matthew Flatt wrote: At Thu, 21 May 2015 07:15:14 -0600, Matthew Flatt wrote: Otherwise, be prepared for me to come back in a few weeks and lobby for moving to a new macro expander. Here's the proposal: let's switch on July 16. Switch means that I'd merge the new macro expander to the master branch of the development repository. Perhaps a mixture of excitement and trepidation is stifling replies. :) +10. I'm really looking forward to it. Neil ⊥ -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Closing big-bang windows
I have for years hoped to find time to think about 'distributing state' over handlers in big-bang because I am perfectly aware of the scaling up limitations. Your hashtable idea might be worth exploring. Tony and I are also considering his actor system as a source of ideas. This may also give us a handle at a special-purpose gc as Tony noted yesterday. But now I am way off stuff I have done, and I don't like to discuss things that I might do so forgive me for this much and I'll stop now -- Matthias -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
Providing #f as the third argument to `local-expand` means that (+ i j) is expanded only as far as exposing the primitive function-call form, also known as `#%plain-app`: (#%plain-app + i j) When `i` is encountered later, there's no binding in the compile-time environment, because the internal-definition context has been discarded as the `my-def-stx` macro returned. Probably you want to replace the `#f` with `null` (which means expand without stopping). Another possibility is to expand to a `letrec-syntaxes+values` form to bind `i` and `j`. At Tue, 23 Jun 2015 02:13:19 -0400, Thomas Dickerson wrote: I seem to be missing some key ingredient here. The following really simply test-case, using let-syntaxes, works as expected: (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) #'(let-syntaxes ([(id ...) rhs]) expr)]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) Trying the same thing, but with this: (require (for-syntax syntax/context)) (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) (let* ([intdef (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (syntax-list #'(id ...)) (local-transformer-expand #'rhs 'expression null) intdef) (internal-definition-context-seal intdef) (local-expand #'expr ctx #f intdef))]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) instead, gives me i: undefined; cannot reference an identifier before its definition. Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Mon, Jun 22, 2015 at 11:39 PM, Matthew Flatt mfl...@cs.utah.edu wrote: Probably you don't want to work with namespaces, which are intended more for run-time reflection. For an example of turning internal definitions into 'letrec-syntaxes+values', try the implementation of 'racket/block'. On Jun 23, 2015, at 10:06 AM, Thomas Dickerson thomas_dicker...@brown.edu wrote: Update / addendum: I was also able to fairly trivially extend Alex's code using let-syntax to have the more hygienic behavior for where Accum is/is-not visible, but let-syntax ends up leaving an additional layer of empty (let-values() ...) behind. The documentation for let-syntax makes the following claim - The evaluation of each trans-expr is parameterized to set current-namespace to a namespace that shares bindings and variables with the namespace being used to expand the let-syntax form, except that its base phase is one greater. which seems very much related to what I'd like to accomplish (and Shriram's suggestion that I mentioned in the original post); however, I see no evidence of this actually taking place in the Racket source-code, it just appears to desugar, with very few bells and whistles, to letrec-syntaxes+values which evidently is implemented in the C code. Digging into syntax-parameterize shows that, unsurprisingly, this is also how syntax-parameterize gets desugared, with a few more bells and whistles. So I guess at this point the remainder of my question boils down to this: can someone offer any insight into the process of turning macros which are introduced by let-syntax or equivalent into macros which are introduced implicitly by an internal-definition-context argument to local-expand, or by explicit namespace manipulation as hinted at in the let-syntax documentation (but which I can't turn up anywhere). On Monday, June 22, 2015 at 5:35:50 PM UTC-4, Thomas Dickerson wrote: Thanks for the effort that went into figuring that out! A couple first thoughts on the implementation: To first order, this is exactly what I want to be able to do (and it elegantly avoids local-expand by reasoning about expansion order); however, as a general pattern, it's a bit unhygienic in that Accum is now in the global namespace, which precludes using it as a child macro for other constructs, and prevents specific instantiations of Loop from requesting a different name for Accum to cooperate in nested loops. I also noticed that (syntax-parameterize) isn't totally transparent in the expanded syntax - it leaves a bunch of empty (let-values () ...) behind, which is fine for Racket, but problematic in my target use-case of emitting something which ultimately needs to be an entirely different language. This is why my experiments have all involved local-expand - I want to introduce expand-time names without introducing wrapping let-syntaxes (or similar) forms around my body code. On Saturday, June 20, 2015 at 2:24:40 PM UTC-4, Alex Knauth wrote: On Jun 19, 2015, at 7:44 PM, Thomas Dickerson
[racket-users] Re: HTTP Cookies
It solved itself: I had forgotten to set the `Content-Type` of the POST request. Here's a working example of cookies in action: http://www.bahmanm.com/blogs/grab-packt-racket-scheme -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] try a new macro expander
Excited! On Tue, Jun 23, 2015 at 10:30 AM, Neil Toronto neil.toro...@gmail.com wrote: On 06/22/2015 08:25 AM, Matthew Flatt wrote: At Thu, 21 May 2015 07:15:14 -0600, Matthew Flatt wrote: Otherwise, be prepared for me to come back in a few weeks and lobby for moving to a new macro expander. Here's the proposal: let's switch on July 16. Switch means that I'd merge the new macro expander to the master branch of the development repository. Perhaps a mixture of excitement and trepidation is stifling replies. :) +10. I'm really looking forward to it. Neil ⊥ -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Closing big-bang windows
John Carmack: My son's game has a level editor as well as a game loop, and we switch between them. However, each new big-bang call creates a new window, leaving the previous ones inert on the screen. How can we close the windows? Matthias Felleisen: But people wanted it to stay open so that they could see the final score of their games etc. I guess I could add a close-on-stop clauses for programmers such as your son but it sounds almost like he's ready to move on to racket proper, as in use the Windowing API directly. If I understand correctly, a manual (close-all-big-bang-windows) callable from the REPL would be enough in this case? /Jens Axel -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] db: nested transactions
Yes, that should be fine. One note about your sample code: the isolation mode of inner transactions must be #f (the default); you can't change isolation levels once you've started an outer transaction. Also keep in mind that nested transactions are not supported for ODBC connections. Ryan On 06/22/2015 05:05 AM, George Neuner wrote: Hi all, I have what I hope is a quick question. WIth appropriate care to pair start and commit/rollback, is it safe to use call-with-transaction and start-transaction together? e.g., (call-with-transaction dbc (lambda () : (start-transaction dbc #:isolation 'serializable) : (if (needs-rollback? dbc) (rollback-transaction dbc) (commit-transaction dbc)) : ) #:isolation 'read-committed ) or the reverse: (start-transaction dbc #:isolation 'repeatable-read) : (call-with-transaction dbc (lambda () : ) #:isolation 'serializable) : (if (needs-rollback? dbc) (rollback-transaction dbc) (commit-transaction dbc)) I am adding functionality involving sub-transactions to an existing code base that uses call-with-transaction pretty much exclusively and I'm hoping not to have to change the existing framework. Thanks, George -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com mailto:racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] try a new macro expander
. Awesome that Racket keeps pushing the envelope on meta-programming. It /is/ exciting. I'm somewhat quiet because I'm still absorbing it as I get the time. There has been chatter on IRC too. Also, very cool that mflatt is being so open with the community during the dev cycle. Bring it on. -- Anthony Carrico -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. signature.asc Description: OpenPGP digital signature
[racket-users] NEED || QA Automation Analyst || San Francisco, CA || Locals
Hi, This is Aanchal from Technology resource Group. Below is the job description and requirements for your perusal and please contact me if having any questions or concerns. *If you are available and meet the requirements please respond with your updated resume in a Microsoft Word formatted document along with your desired pay rate.* *If you are not interested, would appreciate if you refer someone for this position.* *Role: QA Automation Analyst* *Location: San Francisco, CA* *Duration: 12 Months (Extension possible) * *Job Description:* *I have a position in San Francisco, CA that will be a 1-year engagement. They need a Strong QA Automation Analyst that has experience Selenium, WebDriver and Good Java programming. Description is below, please let me know if you're interested .* *1. Strong knowledge/skills on QA disciplines and tools* *2. Experience using Selenium and WebDriver for test automation* *3. Experiences on using and testing c apis* *4. Good Java programming skills for test automation* *5. Understands how code debugging works.* *Need to know Java and Selenium* *NEED TO KNOW JAVA* Thanks and Regards, Aanchal Arora | Technical Recruiter Technology Resource Group Inc. 3736 Hillsdale Court Santa Clara, CA 95051 Office:408-709-1760 Ext : 812 | Direct: 408-826-8378 Gtalk/YM: http://www.tresourceinc.com/ aanchalarora825 | Fax: 408-884-2409 aanc...@tresourceinc.com | www.tresourceinc.com -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
Okay - for posterity's sake, here's an updated version of Alex's code that supports nested Loop/Accum, and doesn't leave any syntactic residue after expansion. This is now what I set out to accomplish with my original set of questions: #lang racket/base (require racket/stxparam (for-syntax racket/base racket/set racket/syntax syntax/parse syntax/stx syntax/context)) (define-syntax Loop (lambda (stx) (syntax-parse stx [(Loop accum-id:id up-to-expr:expr body:expr ...+) (let* ([defs (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (list #'accum-id) (local-transformer-expand #'(let ([vars (mutable-set)]) (lambda ([stx #f]) (if (syntax? stx) (syntax-parse stx [(accum-id x:id dx:expr) (set-add! vars (syntax-local-introduce #'x)) #'(set! x (+ x dx))]) vars))) 'expression null) defs) (internal-definition-context-seal defs) (with-syntax* ([(body ...) (stx-map (lambda (body) (with-syntax ([body body]) (local-expand #'body ctx null defs))) #'(body ...))] [(init ...) (map (lambda (var) (with-syntax ([var (syntax-local-introduce var)]) #'(set! var 0))) (set-list ((syntax-local-value (internal-definition-context-apply defs #'accum-id) #f defs]) #'(let ([up-to up-to-expr]) (letrec ([loop (lambda (n) body ... (let ([n (add1 n)]) (if ( n up-to) (loop n) (void]) init ... (loop 0)] [(Loop up-to-expr:expr body:expr ...+) (with-syntax ([Accum (datum-syntax stx 'Accum)]) #'(Loop Accum up-to-expr body ...))]))) (let ([x (void)] [y (void)] [z (void)]) (Loop 2 (let ([dx 1] [dy 2] [dz 3]) (Accum x dx) (Loop AccumInner 2 (printf x = ~v, y = ~v, z = ~v\n x y z) (Accum y dy) (AccumInner z dz) One last question - the change to using local-expand meant that the loop body was no longer happy accepting define-values forms and raised Not in a definition context errors. I can use let to accomplish the same thing without any problems, but if someone could explain what changes would need to be made to the local-expand call for that to work, I'd be grateful (for my own understanding). Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Tue, Jun 23, 2015 at 11:17 AM, Thomas Dickerson thomas_dicker...@brown.edu wrote: On Tuesday, June 23, 2015 at 8:30:32 AM UTC-4, Matthew Flatt wrote: Providing #f as the third argument to `local-expand` means that (+ i j) is expanded only as far as exposing the primitive function-call form, also known as `#%plain-app`: (#%plain-app + i j) When `i` is encountered later, there's no binding in the compile-time environment, because the internal-definition context has been discarded as the `my-def-stx` macro returned. Probably you want to replace the `#f` with `null` (which means expand without stopping). Got it - this makes sense, thanks. Another possibility is to expand to a `letrec-syntaxes+values` form to bind `i` and `j`. This is actually what I'm trying to avoid - see the earlier note on why I need a solution that won't leave behind empty (let-values () ...) forms (or any other Racket-specific forms) in the output syntax. At Tue, 23 Jun 2015 02:13:19 -0400, Thomas Dickerson wrote: I seem to be missing some key ingredient here. The following really simply test-case, using let-syntaxes, works as expected: (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) #'(let-syntaxes ([(id ...) rhs]) expr)]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) Trying the same thing, but with this: (require (for-syntax syntax/context)) (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) (let* ([intdef
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
I ran into this issue recently. The right answer for me was to write a trampolining macro. define-values is treated specially by the macro expander and thus can't be handled easily in a local expand. The pattern I ended up using (adapted from an old mailing list post by Ryan and a discussion with Matthew and Robby) is the following: 1) expand in whatever the current syntax context is and add define-values to the stop list (to prevent attempting to expand it outside of a definition context) (local-expand my-stx (syntax-local-context) (list #'define-values)) 2) Use syntax-case on the resulting syntax to find any occurrences of define-values, then replace the body of each define-values with a new call to your macro: (define-syntax (my-syntax stx) (syntax-case stx () [(my-syntax expr) (syntax-case (local-expand stx (syntax-local-context) (list #'define-values)) () [(define-values (id) expr) (define-values (id) (my-syntax expr))] [other other])])) Note this code might not work verbatim... I abstracted it from my example as I pasted it in... This pattern seems fairly robust for getting your macro to run on all of the expanded code in a local context. The downside is that your macro will need to work correctly in this staged fashion where things run as the expander gets to them. Hope this helps. Cheers, Scott On Tue, Jun 23, 2015 at 2:23 PM, Sam Tobin-Hochstadt sa...@cs.indiana.edu wrote: Based on the documentation, I thought that the right answer would be `(list (gensym))` but that didn't work -- hopefully someone else knows. Sam On Tue, Jun 23, 2015 at 4:43 PM, Thomas Dickerson thomas_dicker...@brown.edu wrote: I thought that might be the case, but the documentation is pretty dense (and self-referential), so it's not clear what the correct value for that argument is. Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Tue, Jun 23, 2015 at 3:57 PM, Sam Tobin-Hochstadt sa...@cs.indiana.edu wrote: To fix your last issue, you probably want to provide a different value as the `context-v` argument (the 2nd one) to `local-expand`. Sam On Tue, Jun 23, 2015 at 3:46 PM Thomas Dickerson thomas_dicker...@brown.edu wrote: Okay - for posterity's sake, here's an updated version of Alex's code that supports nested Loop/Accum, and doesn't leave any syntactic residue after expansion. This is now what I set out to accomplish with my original set of questions: #lang racket/base (require racket/stxparam (for-syntax racket/base racket/set racket/syntax syntax/parse syntax/stx syntax/context)) (define-syntax Loop (lambda (stx) (syntax-parse stx [(Loop accum-id:id up-to-expr:expr body:expr ...+) (let* ([defs (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (list #'accum-id) (local-transformer-expand #'(let ([vars (mutable-set)]) (lambda ([stx #f]) (if (syntax? stx) (syntax-parse stx [(accum-id x:id dx:expr) (set-add! vars (syntax-local-introduce #'x)) #'(set! x (+ x dx))]) vars))) 'expression null) defs) (internal-definition-context-seal defs) (with-syntax* ([(body ...) (stx-map (lambda (body) (with-syntax ([body body]) (local-expand #'body ctx null defs))) #'(body ...))] [(init ...) (map (lambda (var) (with-syntax ([var (syntax-local-introduce var)]) #'(set! var 0))) (set-list ((syntax-local-value (internal-definition-context-apply defs #'accum-id) #f defs]) #'(let ([up-to up-to-expr]) (letrec ([loop (lambda (n) body ... (let ([n (add1 n)]) (if ( n up-to) (loop n) (void]) init ... (loop 0)] [(Loop up-to-expr:expr body:expr ...+) (with-syntax ([Accum (datum-syntax stx 'Accum)]) #'(Loop Accum up-to-expr body ...))]))) (let ([x (void)] [y (void)] [z (void)]) (Loop 2 (let ([dx 1] [dy 2] [dz 3])
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
I thought that might be the case, but the documentation is pretty dense (and self-referential), so it's not clear what the correct value for that argument is. Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Tue, Jun 23, 2015 at 3:57 PM, Sam Tobin-Hochstadt sa...@cs.indiana.edu wrote: To fix your last issue, you probably want to provide a different value as the `context-v` argument (the 2nd one) to `local-expand`. Sam On Tue, Jun 23, 2015 at 3:46 PM Thomas Dickerson thomas_dicker...@brown.edu wrote: Okay - for posterity's sake, here's an updated version of Alex's code that supports nested Loop/Accum, and doesn't leave any syntactic residue after expansion. This is now what I set out to accomplish with my original set of questions: #lang racket/base (require racket/stxparam (for-syntax racket/base racket/set racket/syntax syntax/parse syntax/stx syntax/context)) (define-syntax Loop (lambda (stx) (syntax-parse stx [(Loop accum-id:id up-to-expr:expr body:expr ...+) (let* ([defs (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (list #'accum-id) (local-transformer-expand #'(let ([vars (mutable-set)]) (lambda ([stx #f]) (if (syntax? stx) (syntax-parse stx [(accum-id x:id dx:expr) (set-add! vars (syntax-local-introduce #'x)) #'(set! x (+ x dx))]) vars))) 'expression null) defs) (internal-definition-context-seal defs) (with-syntax* ([(body ...) (stx-map (lambda (body) (with-syntax ([body body]) (local-expand #'body ctx null defs))) #'(body ...))] [(init ...) (map (lambda (var) (with-syntax ([var (syntax-local-introduce var)]) #'(set! var 0))) (set-list ((syntax-local-value (internal-definition-context-apply defs #'accum-id) #f defs]) #'(let ([up-to up-to-expr]) (letrec ([loop (lambda (n) body ... (let ([n (add1 n)]) (if ( n up-to) (loop n) (void]) init ... (loop 0)] [(Loop up-to-expr:expr body:expr ...+) (with-syntax ([Accum (datum-syntax stx 'Accum)]) #'(Loop Accum up-to-expr body ...))]))) (let ([x (void)] [y (void)] [z (void)]) (Loop 2 (let ([dx 1] [dy 2] [dz 3]) (Accum x dx) (Loop AccumInner 2 (printf x = ~v, y = ~v, z = ~v\n x y z) (Accum y dy) (AccumInner z dz) One last question - the change to using local-expand meant that the loop body was no longer happy accepting define-values forms and raised Not in a definition context errors. I can use let to accomplish the same thing without any problems, but if someone could explain what changes would need to be made to the local-expand call for that to work, I'd be grateful (for my own understanding). Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Tue, Jun 23, 2015 at 11:17 AM, Thomas Dickerson thomas_dicker...@brown.edu wrote: On Tuesday, June 23, 2015 at 8:30:32 AM UTC-4, Matthew Flatt wrote: Providing #f as the third argument to `local-expand` means that (+ i j) is expanded only as far as exposing the primitive function-call form, also known as `#%plain-app`: (#%plain-app + i j) When `i` is encountered later, there's no binding in the compile-time environment, because the internal-definition context has been discarded as the `my-def-stx` macro returned. Probably you want to replace the `#f` with `null` (which means expand without stopping). Got it - this makes sense, thanks. Another possibility is to expand to a `letrec-syntaxes+values` form to bind `i` and `j`. This is actually what I'm trying to avoid - see the earlier note on why I need a solution that won't leave behind empty (let-values () ...) forms (or any other Racket-specific forms) in the output syntax. At Tue, 23 Jun 2015 02:13:19 -0400, Thomas Dickerson wrote: I seem to be missing some
Re: [racket-users] Racket v6.2
On 06/19/2015 11:19 PM, Ryan Culpepper wrote: With this release we are taking a major step forward to get our user community even more involved than in the past... It looks like I'm running currently running a snapshot. I've ran from github before, but I'll admit I'm not sure where I'd go to understand how to build from the multiple github repos. If instructions exist, it might be time to link to them under the http://racket-lang.org/ contrib. Hopefully that would include: * how to check-out Racket and whatever other repos, * build out-of-tree, * run racket, * sync, * build again. -- Anthony Carrico -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. signature.asc Description: OpenPGP digital signature
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
Based on the documentation, I thought that the right answer would be `(list (gensym))` but that didn't work -- hopefully someone else knows. Sam On Tue, Jun 23, 2015 at 4:43 PM, Thomas Dickerson thomas_dicker...@brown.edu wrote: I thought that might be the case, but the documentation is pretty dense (and self-referential), so it's not clear what the correct value for that argument is. Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Tue, Jun 23, 2015 at 3:57 PM, Sam Tobin-Hochstadt sa...@cs.indiana.edu wrote: To fix your last issue, you probably want to provide a different value as the `context-v` argument (the 2nd one) to `local-expand`. Sam On Tue, Jun 23, 2015 at 3:46 PM Thomas Dickerson thomas_dicker...@brown.edu wrote: Okay - for posterity's sake, here's an updated version of Alex's code that supports nested Loop/Accum, and doesn't leave any syntactic residue after expansion. This is now what I set out to accomplish with my original set of questions: #lang racket/base (require racket/stxparam (for-syntax racket/base racket/set racket/syntax syntax/parse syntax/stx syntax/context)) (define-syntax Loop (lambda (stx) (syntax-parse stx [(Loop accum-id:id up-to-expr:expr body:expr ...+) (let* ([defs (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (list #'accum-id) (local-transformer-expand #'(let ([vars (mutable-set)]) (lambda ([stx #f]) (if (syntax? stx) (syntax-parse stx [(accum-id x:id dx:expr) (set-add! vars (syntax-local-introduce #'x)) #'(set! x (+ x dx))]) vars))) 'expression null) defs) (internal-definition-context-seal defs) (with-syntax* ([(body ...) (stx-map (lambda (body) (with-syntax ([body body]) (local-expand #'body ctx null defs))) #'(body ...))] [(init ...) (map (lambda (var) (with-syntax ([var (syntax-local-introduce var)]) #'(set! var 0))) (set-list ((syntax-local-value (internal-definition-context-apply defs #'accum-id) #f defs]) #'(let ([up-to up-to-expr]) (letrec ([loop (lambda (n) body ... (let ([n (add1 n)]) (if ( n up-to) (loop n) (void]) init ... (loop 0)] [(Loop up-to-expr:expr body:expr ...+) (with-syntax ([Accum (datum-syntax stx 'Accum)]) #'(Loop Accum up-to-expr body ...))]))) (let ([x (void)] [y (void)] [z (void)]) (Loop 2 (let ([dx 1] [dy 2] [dz 3]) (Accum x dx) (Loop AccumInner 2 (printf x = ~v, y = ~v, z = ~v\n x y z) (Accum y dy) (AccumInner z dz) One last question - the change to using local-expand meant that the loop body was no longer happy accepting define-values forms and raised Not in a definition context errors. I can use let to accomplish the same thing without any problems, but if someone could explain what changes would need to be made to the local-expand call for that to work, I'd be grateful (for my own understanding). Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Tue, Jun 23, 2015 at 11:17 AM, Thomas Dickerson thomas_dicker...@brown.edu wrote: On Tuesday, June 23, 2015 at 8:30:32 AM UTC-4, Matthew Flatt wrote: Providing #f as the third argument to `local-expand` means that (+ i j) is expanded only as far as exposing the primitive function-call form, also known as `#%plain-app`: (#%plain-app + i j) When `i` is encountered later, there's no binding in the compile-time environment, because the internal-definition context has been discarded as the `my-def-stx` macro returned. Probably you want to replace the `#f` with `null` (which means expand without stopping). Got it - this makes sense, thanks. Another possibility is to expand to a `letrec-syntaxes+values` form to bind `i` and `j`. This is actually what I'm trying to avoid - see the earlier
Re: [racket-users] Racket v6.2
PS The 'extra-pkgs' directory is a tiny bit special: http://docs.racket-lang.org/pkg/git-workflow.html?q=git#%28part._clone-link%29 On Tue, Jun 23, 2015 at 5:39 PM, Jay McCarthy jay.mccar...@gmail.com wrote: On Tue, Jun 23, 2015 at 4:26 PM, Anthony Carrico acarr...@memebeam.org wrote: On 06/19/2015 11:19 PM, Ryan Culpepper wrote: With this release we are taking a major step forward to get our user community even more involved than in the past... It looks like I'm running currently running a snapshot. I've ran from github before, but I'll admit I'm not sure where I'd go to understand how to build from the multiple github repos. If instructions exist, it might be time to link to them under the http://racket-lang.org/ contrib. Hopefully that would include: * how to check-out Racket and whatever other repos, * build out-of-tree, * run racket, * sync, * build again. Here's what I do for building from git, and I think it's the simplest thing: $ git clone https://github.com/plt/racket $ cd racket $ make This clones a single (small) repository and then builds everything. It will automatically install the latest version of whatever other packages you need without actually cloning any of the other repositories. This means that you have a pretty minimal connection to git. When you need to update again, you can just update racket and then do another make and it will download the updates for the packages too. Now, sometimes you will actually want to have the git repos of other packages. That's easy too. Since I work on the Web server, here's what I did: # Create a helpful directory. There's nothing special about this name, but I like it $ mkdir extra-pkgs $ cd extra-pkgs # Tell racket to switch the web-server package from being a tar-ball install to being a git clone $ raco pkg update --clone web-server Now I'm good to go to $ cd web-server $ ed web-server-lib/web-server/main.rkt and so forth. Something that is neat about the new world is that it is easy to have a released version of Racket downloaded from the site, but have a git clone of some small set of other package repos that you are doing development on. The only difference will be the first three steps. I hope this helps, 3 Jay -- Jay McCarthy http://jeapostrophe.github.io Wherefore, be not weary in well-doing, for ye are laying the foundation of a great work. And out of small things proceedeth that which is great. - DC 64:33 -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Racket v6.2
Yes, it is already included in the .gitignore file. I guess I meant it's not special to _Racket_, but it is useful to have a convention for stuff like git and helping others. :) Jay On Tue, Jun 23, 2015 at 11:30 PM, Matthew Butterick m...@mbtype.com wrote: PS The 'extra-pkgs' directory is a tiny bit special: http://docs.racket-lang.org/pkg/git-workflow.html?q=git#%28part._clone-link%29 On Tue, Jun 23, 2015 at 5:39 PM, Jay McCarthy jay.mccar...@gmail.com wrote: On Tue, Jun 23, 2015 at 4:26 PM, Anthony Carrico acarr...@memebeam.org wrote: On 06/19/2015 11:19 PM, Ryan Culpepper wrote: With this release we are taking a major step forward to get our user community even more involved than in the past... It looks like I'm running currently running a snapshot. I've ran from github before, but I'll admit I'm not sure where I'd go to understand how to build from the multiple github repos. If instructions exist, it might be time to link to them under the http://racket-lang.org/ contrib. Hopefully that would include: * how to check-out Racket and whatever other repos, * build out-of-tree, * run racket, * sync, * build again. Here's what I do for building from git, and I think it's the simplest thing: $ git clone https://github.com/plt/racket $ cd racket $ make This clones a single (small) repository and then builds everything. It will automatically install the latest version of whatever other packages you need without actually cloning any of the other repositories. This means that you have a pretty minimal connection to git. When you need to update again, you can just update racket and then do another make and it will download the updates for the packages too. Now, sometimes you will actually want to have the git repos of other packages. That's easy too. Since I work on the Web server, here's what I did: # Create a helpful directory. There's nothing special about this name, but I like it $ mkdir extra-pkgs $ cd extra-pkgs # Tell racket to switch the web-server package from being a tar-ball install to being a git clone $ raco pkg update --clone web-server Now I'm good to go to $ cd web-server $ ed web-server-lib/web-server/main.rkt and so forth. Something that is neat about the new world is that it is easy to have a released version of Racket downloaded from the site, but have a git clone of some small set of other package repos that you are doing development on. The only difference will be the first three steps. I hope this helps, 3 Jay -- Jay McCarthy http://jeapostrophe.github.io Wherefore, be not weary in well-doing, for ye are laying the foundation of a great work. And out of small things proceedeth that which is great. - DC 64:33 -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- Jay McCarthy http://jeapostrophe.github.io Wherefore, be not weary in well-doing, for ye are laying the foundation of a great work. And out of small things proceedeth that which is great. - DC 64:33 -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Macro-introducing macros with inter-macro communication channel
I seem to be missing some key ingredient here. The following really simply test-case, using let-syntaxes, works as expected: (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) #'(let-syntaxes ([(id ...) rhs]) expr)]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) Trying the same thing, but with this: (require (for-syntax syntax/context)) (define-syntax my-def-stx (lambda (stx) (syntax-case stx (my-def-stx) [(my-def-stx (id ...) rhs expr) (let* ([intdef (syntax-local-make-definition-context)] [ctx (generate-expand-context)]) (syntax-local-bind-syntaxes (syntax-list #'(id ...)) (local-transformer-expand #'rhs 'expression null) intdef) (internal-definition-context-seal intdef) (local-expand #'expr ctx #f intdef))]))) (my-def-stx (i j) (values (lambda (stx) #'3) (lambda (stx) #'4)) (+ i j)) instead, gives me i: undefined; cannot reference an identifier before its definition. Thomas Dickerson Brown University Department of Computer Science 115 Waterman St, 4th Floor Providence, RI 02912 802-458-0637 On Mon, Jun 22, 2015 at 11:39 PM, Matthew Flatt mfl...@cs.utah.edu wrote: Probably you don't want to work with namespaces, which are intended more for run-time reflection. For an example of turning internal definitions into 'letrec-syntaxes+values', try the implementation of 'racket/block'. On Jun 23, 2015, at 10:06 AM, Thomas Dickerson thomas_dicker...@brown.edu wrote: Update / addendum: I was also able to fairly trivially extend Alex's code using let-syntax to have the more hygienic behavior for where Accum is/is-not visible, but let-syntax ends up leaving an additional layer of empty (let-values() ...) behind. The documentation for let-syntax makes the following claim - The evaluation of each trans-expr is parameterized to set current-namespace to a namespace that shares bindings and variables with the namespace being used to expand the let-syntax form, except that its base phase is one greater. which seems very much related to what I'd like to accomplish (and Shriram's suggestion that I mentioned in the original post); however, I see no evidence of this actually taking place in the Racket source-code, it just appears to desugar, with very few bells and whistles, to letrec-syntaxes+values which evidently is implemented in the C code. Digging into syntax-parameterize shows that, unsurprisingly, this is also how syntax-parameterize gets desugared, with a few more bells and whistles. So I guess at this point the remainder of my question boils down to this: can someone offer any insight into the process of turning macros which are introduced by let-syntax or equivalent into macros which are introduced implicitly by an internal-definition-context argument to local-expand, or by explicit namespace manipulation as hinted at in the let-syntax documentation (but which I can't turn up anywhere). On Monday, June 22, 2015 at 5:35:50 PM UTC-4, Thomas Dickerson wrote: Thanks for the effort that went into figuring that out! A couple first thoughts on the implementation: To first order, this is exactly what I want to be able to do (and it elegantly avoids local-expand by reasoning about expansion order); however, as a general pattern, it's a bit unhygienic in that Accum is now in the global namespace, which precludes using it as a child macro for other constructs, and prevents specific instantiations of Loop from requesting a different name for Accum to cooperate in nested loops. I also noticed that (syntax-parameterize) isn't totally transparent in the expanded syntax - it leaves a bunch of empty (let-values () ...) behind, which is fine for Racket, but problematic in my target use-case of emitting something which ultimately needs to be an entirely different language. This is why my experiments have all involved local-expand - I want to introduce expand-time names without introducing wrapping let-syntaxes (or similar) forms around my body code. On Saturday, June 20, 2015 at 2:24:40 PM UTC-4, Alex Knauth wrote: On Jun 19, 2015, at 7:44 PM, Thomas Dickerson thomas_dicker...@brown.edu wrote: I was intending for that example to have the variables be defined outside the macro, but being able to create the (set! ...) forms outside should mean I could also hypothetically create let/define-values forms. This is why I originally specified being able to effect generation of both prologue + epilogue code. I figured this out for code that will be expanded after the body: #lang racket/base (require racket/stxparam (for-syntax racket/base syntax/parse racket/set )) ;; (syntax-parameter-value vars) : (U #f (MutableSetof Identifier)) (define-syntax-parameter vars #f)
Re: [racket-users] Gear VR
We welcome all posts connected to Racket. Post away. -- Matthias p.s. The question is whether you get suitable feedback. My life is so abstract, I sometimes wonder what reality is :-) On Jun 23, 2015, at 7:36 PM, John Carmack wrote: The intersection of Gear VR owners and Racket users may consist of just me at the moment, but if anyone else here is interested in discussing the work I am doing with driving VR by Racket/Scheme, I would welcome the input. Would that be an appropriate topic on the list? -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Racket v6.2
On Tue, Jun 23, 2015 at 4:26 PM, Anthony Carrico acarr...@memebeam.org wrote: On 06/19/2015 11:19 PM, Ryan Culpepper wrote: With this release we are taking a major step forward to get our user community even more involved than in the past... It looks like I'm running currently running a snapshot. I've ran from github before, but I'll admit I'm not sure where I'd go to understand how to build from the multiple github repos. If instructions exist, it might be time to link to them under the http://racket-lang.org/ contrib. Hopefully that would include: * how to check-out Racket and whatever other repos, * build out-of-tree, * run racket, * sync, * build again. Here's what I do for building from git, and I think it's the simplest thing: $ git clone https://github.com/plt/racket $ cd racket $ make This clones a single (small) repository and then builds everything. It will automatically install the latest version of whatever other packages you need without actually cloning any of the other repositories. This means that you have a pretty minimal connection to git. When you need to update again, you can just update racket and then do another make and it will download the updates for the packages too. Now, sometimes you will actually want to have the git repos of other packages. That's easy too. Since I work on the Web server, here's what I did: # Create a helpful directory. There's nothing special about this name, but I like it $ mkdir extra-pkgs $ cd extra-pkgs # Tell racket to switch the web-server package from being a tar-ball install to being a git clone $ raco pkg update --clone web-server Now I'm good to go to $ cd web-server $ ed web-server-lib/web-server/main.rkt and so forth. Something that is neat about the new world is that it is easy to have a released version of Racket downloaded from the site, but have a git clone of some small set of other package repos that you are doing development on. The only difference will be the first three steps. I hope this helps, 3 Jay -- Jay McCarthy http://jeapostrophe.github.io Wherefore, be not weary in well-doing, for ye are laying the foundation of a great work. And out of small things proceedeth that which is great. - DC 64:33 -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Racket v6.2
On 06/23/2015 04:26 PM, Anthony Carrico wrote: On 06/19/2015 11:19 PM, Ryan Culpepper wrote: With this release we are taking a major step forward to get our user community even more involved than in the past... It looks like I'm running currently running a snapshot. I've ran from github before, but I'll admit I'm not sure where I'd go to understand how to build from the multiple github repos. If instructions exist, it might be time to link to them under the http://racket-lang.org/ I guess that would be: https://github.com/plt/racket/blob/master/INSTALL.txt The 550 lines of which start with: For Unix platforms, instead of using this source repository, consider getting source for the current Racket release from http://download.racket-lang.org/ or get a source snapshot (updated daily) from http://pre.racket-lang.org/installers/; which is how I probably ended up with my random snapshot rather than git :). -- Anthony Carrico -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. signature.asc Description: OpenPGP digital signature
[racket-users] Gear VR
The intersection of Gear VR owners and Racket users may consist of just me at the moment, but if anyone else here is interested in discussing the work I am doing with driving VR by Racket/Scheme, I would welcome the input. Would that be an appropriate topic on the list? -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Gear VR
On 06/23/2015 07:36 PM, John Carmack wrote: The intersection of Gear VR owners and Racket users may consist of just me at the moment, but if anyone else here is interested in discussing the work I am doing with driving VR by Racket/Scheme, I would welcome the input. Would that be an appropriate topic on the list? Very yes. Also, I'm definitely in the intersection: I've just changed research topics to functional 3D, and I've written a rendering engine and modeling API in Racket for it. What part do you have Racket playing in driving VR? Neil ⊥ -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
RE: [racket-users] Gear VR
Here is the overview of the work that I recently sent out internally. I started out with a pure-functional scripting interface, but it very rapidly became imperative, and it is in heavy flux. The sample scripts do capture the general flavor that I want this to have -- I think it will be easy enough to get interesting things happening that it will still tempt people who might be a little hostile to working in a Lisp. -- Here is the first preview of the general purpose VR scripting environment I have been working on. There isn’t anything exciting to look at, but if you squint real hard you can see where it might be going. After I get a bit farther along, we can build a PC version as well for cross platform support. Motivation: Doing VR GUI development in the native apps is unpleasant – you can gut it out in C++ with our current interfaces, but the iteration times and code structure don’t make it a lot of fun. In-editor prototyping is nice in Unity, but actual on-device testing cycle times are terrible, and you wind up with all the bulk of Unity and poor access to the native VR features like TimeWarp layers. With app signing, we have no way for developers to casually share work with each other or limited communities. My solution is to support development of VR applications in a scripting language with several modes: “Web like”, where the script is downloaded from the net for each execution and run by a single signed app that we provide (NetHMD). Fully specified by an app-scheme URI, this allows VR experiences to be launched directly from web pages or app-links on Facebook, which I think is VERY powerful – read about how great something is while browsing on your phone, then just click the link and get the “insert into HMD” dialog and jump right there. VR scripts can link to other VR scripts without leaving VR. There is no direct monetization here, but IAP can eventually be supported. “App like”, where the script is bundled into a conventional apk to be distributed through the store, and the scripting is simply used as a more effective development environment for some classes of applications. “Remote development”, where the script is actually executed in an IDE on a PC, communicating with NetHMD over a TCP connection. This allows sub-second code-change to VR change iteration cycles, and the use of a debugger. There might also be a use for a related mode where a central server directly drives one or more clients. Where it will win first: My “reference application” is the linking of multiple panoramic photos with text and audio annotations. This is a completely obvious application that is not performance sensitive, and even a non-programmer could copy-paste-modify the simple script for this to make a high quality experience. Once I hook up an ExoPlayer interface, this will completely subsume what I wanted to accomplish with “experience files” – the addition of static prop models to panoramic video, linking between different videos, merging of models or panoramas with videos that aren’t fully panoramic (GoPro, etc), and so on. Once I hook up the Social interfaces, this will make it much easier to build trivial “activities” for multi-user experiences – board games, card games, etc. It is already a big help for basic graphics development work – being able to just position a few quads with a custom shader and iterate on the shader programming remotely without rebuilding is a huge win. Implementation: This will be controversial, and I will have a longer discussion about it, but I chose Scheme (a Lisp) for the scripting language. If this all works out, we can eventually make C# and Javascript versions, but I have a bunch of reasons for going this way first. I am using Racket http://racket-lang.org/ for the PC development environment, and Chibi Scheme for the embedded interpreter on Android. Download Racket and walk through their quick-intro-with-pictures to get a feel for the language and you should be able to hack on the sample scripts I have been writing pretty quickly. Note that Racket is a very extended Scheme targeted at desktop apps, the embedded version is just the basic standard. All texture / model / sound resources are loaded and cached from network URI. For testing, you can just paste in any URI from a Google image search, which is convenient. For an actual project development, dropbox should work fine. I am favoring ease of development over performance, and it definitely won’t be suitable for a lot of tasks, but everything we have done with first party apps so far should be at least a candidate for development in this style once it is mature. Everything is super-rough right now, and I keep thinking “one more day of work will clean it up better for people to look at”, but it is past time I at least get this on everyone’s radar. actual Android apk redacted -- it is too
