Re: [racket-users] aws package fails against google cloud storage

['John Clements' via Racket Users]

> On Sep 7, 2016, at 1:02 PM, Sam Tobin-Hochstadt  wrote:
> 
> Isn't there also the option of using the aws pkg at the hash from before the 
> change to v4?

Yes, definitely. (In fact, that’s what I wound up doing, after a git bisect.) I 
might just fork and branch and submit it as a separate pkg to the server.

John

> 
> Sam
> 
> On Wed, Sep 7, 2016 at 3:23 PM 'John Clements' via Racket Users 
>  wrote:
> 
> > On Sep 7, 2016, at 10:48 AM, Tony Garnock-Jones  wrote:
> >
> > On 09/06/2016 02:40 PM, 'John Clements' via Racket Users wrote:
> >> Obvious fixes that I don’t like:
> >>
> >> 1) stop using google cloud storage, starting using Amazon S3.
> >> 2) use the old PLaneT version instead of the shiny new pkg version.
> >>
> >> Any other suggestions?
> >
> > 3) maybe there's a "google API" for GCS?
> 
> Yes, there definitely is. That’s also definitely more work than #2 :).
> 
> >
> > If there is, maybe you can extend or use
> > https://pkgn.racket-lang.org/package/google.
> 
> Ah! didn’t know about this!
> 
> … needs docs, though, and it looks like you don’t have any of the google 
> cloud stuff in there?
> 
> Sigh, always more work to be done.
> 
> John
> 
> 
> 
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Re: [racket-users] aws package fails against google cloud storage

[Sam Tobin-Hochstadt]

Isn't there also the option of using the aws pkg at the hash from before
the change to v4?

Sam

On Wed, Sep 7, 2016 at 3:23 PM 'John Clements' via Racket Users <
racket-users@googlegroups.com> wrote:

>
> > On Sep 7, 2016, at 10:48 AM, Tony Garnock-Jones 
> wrote:
> >
> > On 09/06/2016 02:40 PM, 'John Clements' via Racket Users wrote:
> >> Obvious fixes that I don’t like:
> >>
> >> 1) stop using google cloud storage, starting using Amazon S3.
> >> 2) use the old PLaneT version instead of the shiny new pkg version.
> >>
> >> Any other suggestions?
> >
> > 3) maybe there's a "google API" for GCS?
>
> Yes, there definitely is. That’s also definitely more work than #2 :).
>
> >
> > If there is, maybe you can extend or use
> > https://pkgn.racket-lang.org/package/google.
>
> Ah! didn’t know about this!
>
> … needs docs, though, and it looks like you don’t have any of the google
> cloud stuff in there?
>
> Sigh, always more work to be done.
>
> John
>
>
>
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Re: [racket-users] aws package fails against google cloud storage

['John Clements' via Racket Users]

> On Sep 7, 2016, at 10:48 AM, Tony Garnock-Jones  wrote:
> 
> On 09/06/2016 02:40 PM, 'John Clements' via Racket Users wrote:
>> Obvious fixes that I don’t like:
>> 
>> 1) stop using google cloud storage, starting using Amazon S3.
>> 2) use the old PLaneT version instead of the shiny new pkg version.
>> 
>> Any other suggestions? 
> 
> 3) maybe there's a "google API" for GCS?

Yes, there definitely is. That’s also definitely more work than #2 :).

> 
> If there is, maybe you can extend or use
> https://pkgn.racket-lang.org/package/google.

Ah! didn’t know about this!

… needs docs, though, and it looks like you don’t have any of the google cloud 
stuff in there?

Sigh, always more work to be done.

John



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Re: [racket-users] aws package fails against google cloud storage

[Tony Garnock-Jones]

On 09/06/2016 02:40 PM, 'John Clements' via Racket Users wrote:
> Obvious fixes that I don’t like:
> 
> 1) stop using google cloud storage, starting using Amazon S3.
> 2) use the old PLaneT version instead of the shiny new pkg version.
> 
> Any other suggestions? 

3) maybe there's a "google API" for GCS?

If there is, maybe you can extend or use
https://pkgn.racket-lang.org/package/google.

(Perhaps https://cloud.google.com/storage/docs/json_api/ is the relevant
API?)

Tony

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Re: [racket-users] TR + Hash tables -> chaperone errors ?

[Sam Tobin-Hochstadt]

It's not clear what's going on here without seeing more of the code. A
minimal example isn't necessary, just something runnable.

Sam

On Wed, Sep 7, 2016 at 1:31 PM, 'John Clements' via Racket Users
 wrote:
> I’m getting chaperone errors that seem to occur when calling a function 
> defined in TR that uses hash-union to construct hash tables from another file.
>
> Here’s the text of the error:
>
> procedure chaperone: non-chaperone result;
>  received a 2nd argument that is not a chaperone of the original 2nd argument
>   original: '#hash(("storage-mode" . "local") ("db-password" . 
> "captain_teach") ("tar-binary" . "/usr/bin/tar") ("master-user" . 
> "masteru...@example.com") ("cloud-secret-key" . "YOUR-SECRET-KEY") ("db-name" 
> . "captain_teach_testing") ("zip-binary" . "/usr/bin...
>   received: '#hash(("storage-mode" . "local") ("db-password" . 
> "captain_teach") ("tar-binary" . "/usr/bin/tar") ("master-user" . 
> "masteru...@example.com") ("cloud-secret-key" . "YOUR-SECRET-KEY") ("db-name" 
> . "captain_teach_testing") ("zip-binary" . "/usr/bin…
>
> Here’s what I haven’t done:
>
> 1) updated DrRacket from  6.6.0.4--2016-08-29
> 2) tried to minimize the code
>
> … because there’s an easy workaround. However, if anyone’s interested in this 
> bug, I’d be glad to try to zoom in and isolate a small example and submit a 
> PR.
>
> Thanks!
>
> John
>
>
>
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[racket-users] TR + Hash tables -> chaperone errors ?

['John Clements' via Racket Users]

I’m getting chaperone errors that seem to occur when calling a function defined 
in TR that uses hash-union to construct hash tables from another file.

Here’s the text of the error:

procedure chaperone: non-chaperone result;
 received a 2nd argument that is not a chaperone of the original 2nd argument
  original: '#hash(("storage-mode" . "local") ("db-password" . "captain_teach") 
("tar-binary" . "/usr/bin/tar") ("master-user" . "masteru...@example.com") 
("cloud-secret-key" . "YOUR-SECRET-KEY") ("db-name" . "captain_teach_testing") 
("zip-binary" . "/usr/bin...
  received: '#hash(("storage-mode" . "local") ("db-password" . "captain_teach") 
("tar-binary" . "/usr/bin/tar") ("master-user" . "masteru...@example.com") 
("cloud-secret-key" . "YOUR-SECRET-KEY") ("db-name" . "captain_teach_testing") 
("zip-binary" . "/usr/bin…

Here’s what I haven’t done:

1) updated DrRacket from  6.6.0.4--2016-08-29
2) tried to minimize the code

… because there’s an easy workaround. However, if anyone’s interested in this 
bug, I’d be glad to try to zoom in and isolate a small example and submit a PR.

Thanks!

John



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Re: [racket-users] Re: lambda and the equivalent define / "defun"

[Jon Zeppieri]

On Wed, Sep 7, 2016 at 12:18 PM, Jon Zeppieri  wrote:

>
> Note that this function still generates a list as output. I suppose it
> could instead generate as many values as there are initial elements of xs,
>


Uh, and you can disregard this statement altogether, since it's crazy
[sorry]. `foldl*`, like `foldl`, does not need to generate a list as output.

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Re: [racket-users] Re: lambda and the equivalent define / "defun"

[Jon Zeppieri]

On Wed, Sep 7, 2016 at 12:18 PM, Jon Zeppieri  wrote:

>
>
> ```
> #lang racket/base
>
> (require racket/match)
>
> (define (foldl* proc init . xs)
>   (match xs
> ['() init]
> [(cons x xs) (apply foldl* proc (proc x init) xs)]))
> ```
>
>
I should provide an example. So, if you were using the normal `foldl`,
you'd have:

```
> (foldl cons '() '(1 2 3 4))
'(4 3 2 1)
```

Instead, here's you'd do:

```
> (foldl* cons '() 1 2 3 4)
'(4 3 2 1)
 ```

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Re: [racket-users] Re: lambda and the equivalent define / "defun"

[Jon Zeppieri]

On Wed, Sep 7, 2016 at 11:54 AM, Sanjeev Sharma  wrote:

> Just illustrates the changing structure (increased nesting depth) on each
> recursive call
>
> The initial call to t2 changes the structure of the 
> argument/parameter - it puts in a list where there was no list.
>
> Each recursive call from inside t2 again changes the structure, adding an
> enclosing '() for the  parameter
>
> For the usual (no ) function call It's not an issue for the standard
> car/cdr idiom of walking down recursive structures.
>
>
Okay, I think I follow you.

My first piece of advice (which I think I already mentioned) is to use a
fixed-arity helper function. I understand that you want to do this without
a helper function, but, really, using a helper function is the idiomatic
approach. That said, I'll provide an example of a recursive variable-arity
function that uses `apply` instead. The purpose of `apply` is to use the
individual members of a list as separate arguments to a function call.
Here's a vararg version of `foldl`, limited to a single input "list":

```
#lang racket/base

(require racket/match)

(define (foldl* proc init . xs)
  (match xs
['() init]
[(cons x xs) (apply foldl* proc (proc x init) xs)]))
```

In the recursive case, `apply` is used to provide the elements of xs as
separate arguments to `foldl*`. Note that this function still generates a
list as output. I suppose it could instead generate as many values as there
are initial elements of xs, but that would be an awful pain to use.

- Jon

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Re: [racket-users] Re: lambda and the equivalent define / "defun"

[Sanjeev Sharma]

Just illustrates the changing structure (increased nesting depth) on each 
recursive call

The initial call to t2 changes the structure of the  argument/parameter - 
it puts in a list where there was no list.

Each recursive call from inside t2 again changes the structure, adding an 
enclosing '() for the  parameter

For the usual (no ) function call It's not an issue for the standard 
car/cdr idiom of walking down recursive structures. 

On Wednesday, September 7, 2016 at 9:28:23 AM UTC-4, Jon Zeppieri wrote:

> On Wed, Sep 7, 2016 at 8:33 AM, Sanjeev Sharma  wrote:
> Thanks for joining in.
> 
> 
> 
> The amended question had nothing to do with the earlier example
> 
> 
> 
> Okay.
>  
> 
> 
> I'm  wondering if there's a quick, standard (and easily understood) idiom 
> (without an internal helper function) to recur on the variable argument list y
> 
> 
> 
> I'm still not sure what you mean, and I don't understand what your `t2` 
> example is supposed to do.
> 
> 
> 
> -Jon

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Re: [racket-users] handin server error

[Spencer Florence]

This is a little bit of a hack and weakens the handin server security but
adding the following to the top of your checker file should make this error
go away:

```
 (require handin-server/sandbox)

  (sandbox-path-permissions
   (cons
(list 'read"/")
(sandbox-path-permissions)))
```

--spencer

On Tue, Aug 23, 2016 at 4:15 PM Cameron Swords 
wrote:

> Hi,
>
> I'm trying to set up a handin server for a class this semester, and I'm
> getting the weirdest error message from the client side. Here it is:
>
> submit error: Error in your code --
> file-exists?: `exists' access denied for libobj.so
>
> This seems tied to the fact that the submission file requires another file
> (precisely, it requires 2htdp/image as `(require 2htdp/image)`), and when I
> remove that it works fine (though obviously inhibits the assignment).
>
> Attached are the checker and configuration.
>
> Any help would mean a lot!
>
> Thanks,
> Cameron Swords
>
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Re: [racket-users] TR warning with pict3d-canvas% (in pict3d)

[Tim Brown]

:-(

Latest nightly "snapshot 6.6.0.4--2016-09-07(42f4784/a)" still throws
the error.

Tim

On 07/09/16 15:37, Sam Tobin-Hochstadt wrote:
> I think this is fixed in the git repository. Can you try a snapshot build and 
> see if that works?
> 
> Sam
> 
> On Wed, Sep 7, 2016 at 10:35 AM Tim Brown  > wrote:
> 
> Folks (Neil?),
> 
> Another type issue, but this time with pict3d.
> I am trying to use the following code to display a sphere.
> But there seems to be an issue throwing up a warning. A warning
> that “will become an error in a future release”. A warning that
> also seems to be using up a lot of juice to print itself out.
> 
> Has anyone any idea where to improve the type declarations to
> suppress this?
> 
> ;;
> #lang typed/racket/gui
> (require pict3d)
> 
> (define f (new frame% [label "T"] [width 400] [height 400]))
> 
> (new pict3d-canvas% [parent f] [pict3d (sphere origin 1/2)])
> 
> (send f show #t)
> ;;
> 
> Generates numerous errors of the form:
> 
> cpointer?: contract violation
>   any-wrap/c: Unable to protect opaque value passed as `Any`
>   value: #
>   This warning will become an error in a future release.
>   in: the 1st argument of
>   a part of the or/c of
>   (or/c
>struct-predicate-procedure?/c
>(-> Any boolean?))
>   contract from: (interface for cpointer?)
>   blaming: /pict3d/typed/opengl/ffi-types.rkt
>(assuming the contract is correct)
>   at: /pict3d/typed/opengl/ffi-types.rkt:19.20
> 
> 
> ffi-types.rkt:19 is:
>  ..
>  17  (require/typed
>  18   ffi/unsafe
> *19   [#:opaque CPointer cpointer?]  ; includes Bytes and other things 
> that can be used as cpointers
>  20   [#:opaque CType ctype?]
>  21   )
>  ..
> which seems perfectly innocuous to me :-/
> 
> Tim
> 
> --
> Tim Brown CEng MBCS >
> 
> City Computing Limited · www.cityc.co.uk 
> 
>   City House · Sutton Park Rd · Sutton · Surrey · SM1 2AE · GB
> T:+44 20 8770 2110 · F:+44 20 8770 2130
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[racket-users] TR warning with pict3d-canvas% (in pict3d)

[Tim Brown]

Folks (Neil?),

Another type issue, but this time with pict3d.
I am trying to use the following code to display a sphere.
But there seems to be an issue throwing up a warning. A warning
that “will become an error in a future release”. A warning that
also seems to be using up a lot of juice to print itself out.

Has anyone any idea where to improve the type declarations to
suppress this?

;;
#lang typed/racket/gui
(require pict3d)

(define f (new frame% [label "T"] [width 400] [height 400]))

(new pict3d-canvas% [parent f] [pict3d (sphere origin 1/2)])

(send f show #t)
;;

Generates numerous errors of the form:

cpointer?: contract violation
  any-wrap/c: Unable to protect opaque value passed as `Any`
  value: #
  This warning will become an error in a future release.
  in: the 1st argument of
  a part of the or/c of
  (or/c
   struct-predicate-procedure?/c
   (-> Any boolean?))
  contract from: (interface for cpointer?)
  blaming: /pict3d/typed/opengl/ffi-types.rkt
   (assuming the contract is correct)
  at: /pict3d/typed/opengl/ffi-types.rkt:19.20


ffi-types.rkt:19 is:
 ..
 17  (require/typed
 18   ffi/unsafe
*19   [#:opaque CPointer cpointer?]  ; includes Bytes and other things that can 
be used as cpointers
 20   [#:opaque CType ctype?]
 21   )
 ..
which seems perfectly innocuous to me :-/

Tim

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  City House · Sutton Park Rd · Sutton · Surrey · SM1 2AE · GB
T:+44 20 8770 2110 · F:+44 20 8770 2130

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Re: [racket-users] Re: lambda and the equivalent define / "defun"

[Jon Zeppieri]

On Wed, Sep 7, 2016 at 8:33 AM, Sanjeev Sharma  wrote:

> Thanks for joining in.
>
> The amended question had nothing to do with the earlier example
>

Okay.


>
> I'm  wondering if there's a quick, standard (and easily understood) idiom
> (without an internal helper function) to recur on the variable argument
> list y
>

I'm still not sure what you mean, and I don't understand what your `t2`
example is supposed to do.

-Jon

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Re: [racket-users] typed/racket/gui : possible bug in slider%.get-value

[Sam Tobin-Hochstadt]

Thanks for noticing this! The type of `get-value` was wrong, probably
due to reading `position-integer?` in the docs as `positive-integer?`,
or something like that. I'll push a repair.

Sam

On Wed, Sep 7, 2016 at 7:47 AM, Tim Brown  wrote:
> The following code produces a contract error; I think TR is making
> assumptions that it probably shouldn’t be.
>
> Please could someone investigate.
>
> Thanks,
>
> Tim
>
> ;;;
> #lang typed/racket/gui
> (define f (new frame% [label "Frame"]))
> (define sldr
>(new slider%
> [parent f]
> [max-value 0]
> [min-value -1]
> [init-value 0]
> [callback (λ (sldr cntrl-evnt)
> (displayln (get-v)))]
> [label (format "It's false if negative")]))
>
> (define (get-v) : (Option Index)
>   (define v (send sldr get-value))
>   (printf "~s ~s ~s~%" v (negative? v) (if (negative? v) #f v))
>   (if (negative? v)
>   #f
>   (cast v Index)))
>
> (send f show #t)
> (send sldr set-value -1)
> (get-v)
> ;;;
>
> Runtime error is:
> --
> broke its own contract
>   promised: Index
>   produced: -1
>   in: Index
>   contract from: cast
>   blaming: cast
>(assuming the contract is correct)
>   at: unsaved-editor:18.6
> --
>
> --
> Tim Brown CEng MBCS 
> 
> City Computing Limited · www.cityc.co.uk
>   City House · Sutton Park Rd · Sutton · Surrey · SM1 2AE · GB
> T:+44 20 8770 2110 · F:+44 20 8770 2130
> 
> City Computing Limited registered in London No:1767817.
> Registered Office: City House, Sutton Park Road, Sutton, Surrey, SM1 2AE
> VAT No: GB 918 4680 96
>
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Re: [racket-users] Re: lambda and the equivalent define / "defun"

[Sanjeev Sharma]

Thanks for joining in.

The amended question had nothing to do with the earlier example

I'm  wondering if there's a quick, standard (and easily understood) idiom 
(without an internal helper function) to recur on the variable argument list y

The flatten's not ideal - I may want to retain some sub-list structure 

(define x 4)
(define t2
  (lambda y
(let ((z (car y)))
  (display y)(newline)
  (display (flatten y))(newline)
  (display z)(newline)
  (if (> x 0)
  (begin
(set! x (- x 1))
;(t2 (cdr y)))
(t2 y))
  (void)
(t2 1 2 3 4 5 6)



RETURNS
(1 2 3 4 5 6)
(1 2 3 4 5 6)
1
((1 2 3 4 5 6))
(1 2 3 4 5 6)
(1 2 3 4 5 6)
(((1 2 3 4 5 6)))
(1 2 3 4 5 6)
((1 2 3 4 5 6))
1 2 3 4 5 6
(1 2 3 4 5 6)
(((1 2 3 4 5 6)))
(1 2 3 4 5 6)
(1 2 3 4 5 6)
1 2 3 4 5 6


On Tuesday, September 6, 2016 at 9:04:07 PM UTC-4, Jon Zeppieri wrote:
> On Tue, Sep 6, 2016 at 8:50 PM, Jon Zeppieri  wrote:
>  
> The `(lambda s ...)` is variable-arity, but when you call `ss` internally 
> [...]
> 
> 
> Sorry, I realized after that your `ss` function essentially *is* a wrapper 
> around your `subsets` function -- which is exactly what I was suggesting. 
> However, there's no reason for it to duplicate so much of the work of 
> `subsets`. Since `subsets` works on any list, your definition of `ss` can 
> simply be:
> 
> 
> (define (ss . xs) (subsets xs))
> 
> 
> The only purpose of `ss` is to package up its arguments as a list and pass 
> that list to `subsets`.
> 
> 
> - Jon

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[racket-users] typed/racket/gui : possible bug in slider%.get-value

[Tim Brown]

The following code produces a contract error; I think TR is making
assumptions that it probably shouldn’t be.

Please could someone investigate.

Thanks,

Tim

;;;
#lang typed/racket/gui
(define f (new frame% [label "Frame"]))
(define sldr
   (new slider%
[parent f]
[max-value 0]
[min-value -1]
[init-value 0]
[callback (λ (sldr cntrl-evnt)
(displayln (get-v)))]
[label (format "It's false if negative")]))

(define (get-v) : (Option Index)
  (define v (send sldr get-value))
  (printf "~s ~s ~s~%" v (negative? v) (if (negative? v) #f v))
  (if (negative? v)
  #f
  (cast v Index)))

(send f show #t)
(send sldr set-value -1)
(get-v)
;;;

Runtime error is:
--
broke its own contract
  promised: Index
  produced: -1
  in: Index
  contract from: cast
  blaming: cast
   (assuming the contract is correct)
  at: unsaved-editor:18.6
--

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Re: [racket-users] Racket module creation in org-mode?

[Stephen De Gabrielle]

Sorry, I'm not sure I understand what you mean.

You can use the module form to define more than one module in a file.
There is also the sub-modules functionality.

Both are documented at
https://docs.racket-lang.org/guide/Module_Syntax.html#%28part._module-syntax%29

Kind regards
Stephen
On Tue, 6 Sep 2016 at 19:59, Lawrence Bottorff  wrote:

> Just wondering if creating a module always has to be based on a .rkt file?
> Would there be any way to create, say, modules (one or more) in an org-mode
> file, perhaps one module per babel code block? . . . Trying to get org-mode
> to be more "modular."
>
> --
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Kind regards,
Stephen
--
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Re: [racket-users] aws package fails against google cloud storage

['John Clements' via Racket Users]

> On Sep 6, 2016, at 5:42 PM, Greg Hendershott  
> wrote:
> 
> Until this thread today, I wasn't even aware the AWS package could be
> used with GCS.
> 
> It was a fair amount of work to update things to use v4 sig a year ago:
> 
>  https://github.com/greghendershott/aws/milestone/5?closed=1
> 
> If only I'd known, I could have used GCS compatibility as an excuse
> not to do that. ;)
> 
> Seriously, IIUC the issue is that newer AWS data centers don't even
> support v2 sig anymore. One of the few users of the AWS package that I
> know of had requested v4 so they could use Frankfurt.
> 
> 
> By the way, I myself am not an active user of this package. Originally
> I undertook it as one of the
> suggested-ways-people-could-help-with-Racket. Although I've had
> limited time lately, I'm happy to maintain it. Having said that I'd
> welcome any active user who wanted to do more with it than I current
> have time to do.

Sounds like the right thing to do might be to make a branch and offer it as a 
different racket package. If I have time (somewhat unlikely), I’ll fork this 
repo and do that. Many thanks for all your hard work!

John


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