Re: [racket-users] Rackterm error

[William G Hatch]

On Tue, Sep 05, 2017 at 05:07:41PM -0400, James wrote:

I'm trying out Rackterm for the purpose of running commands put together from a 
GUI but it looks like the thread is crashing as soon as I try to create a 
terminal canvas.  Is it something I am not doing right or is there a bug?  I am 
able to run rackterm/xterm without error and that contains very similar code.





Here's my code:

#lang racket

(require racket/gui
rackterm/private/terminal-canvas
)

(define frame (new frame% [label "Example"]
  (width 800)
  (height 800)
  ))

(send frame show #t)

(define my-term (new terminal-canvas%
   [parent frame]
   [font-size 14]
   [font-name "Courier"]
   [term-var "rackterm"]
   [command-and-args '("ls -lh")]
   [set-title-callback (lambda (title) (send frame set-label 
title))]
   [horiz-margin 2]
   [vert-margin 2]
))


The terminal window appears and then immediately closes with the following 
error message:

"The evaluation thread is no longer running, so no evaluation can take place 
until the next execution.

Exited successfully."



Well, this is caused by my not having actually cleaned up the code for it to be 
used in any sort of general way, rather than specifically only by my one xterm 
(hence terminal canvas is still in the private directory).  But there is a 
`handle-subproc-ended` method that I put a TODO in to make it configurable, but 
currently just kills the canvas, because usually you want an xterm to close 
when the shell inside it exits.  But you could make a subclass that overrides 
that method, or even better, improve my bad code and send a pull request.  Or 
eventually I'll fix things up and release them properly.

Also '("ls -lh") should be '("ls" "-lh").

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Re: [racket-users] Redex v6.4 "broke" LambdaJS

[natasha_danas]

On Wednesday, September 6, 2017 at 2:45:18 PM UTC-4, Sam Caldwell wrote:
> History behind this change: 
> https://groups.google.com/d/msg/racket-users/1SVVqsg4ARQ/vVxKiAvaAQAJ
> Relevant commit: 
> https://github.com/racket/redex/commit/cbb2d88b98fb814325f0d4ee468e1abaf4f6c3a7
> 
> So changing e_1 and e_2 to be anything that is *not* a non-terminal in your 
> model should do the trick.
> 
> -Sam Caldwell
> 
> 
> On Wed, Sep 6, 2017 at 2:39 PM, Ben Greenman  wrote:
> 
> I think it'll work if you delete the underscores, e.g. change "e_1" to "e1".
> 
> 
> 
> 
> On Wed, Sep 6, 2017 at 2:22 PM,   wrote:
> (For some reason the mail I sent to usersracket-lang.org last week never 
> made it to the Google Group, so I'm posting directly...)
> 
> 
> 
> Hello,
> 
> 
> 
> I'm a 2nd year PhD student working with Shriram Krishnamurthi on improving 
> Redex's testing/checking performance and capabilities.
> 
> 
> 
> I was looking to use LambdaJS (http://cs.brown.edu/research/plt/dl/jssem/v1/) 
> as a case study, but unfortunately jscore.ss does not compile under the 
> latest version of Redex.
> 
> 
> 
> The shortcut used in the eval reduction relation
> 
> ...
> 
> with
> 
>    [(--> (σ (in-hole E e_1)) (σ (in-hole E e_2)))
> 
>     (==> e_1 e_2)]))
> 
> now throws an error "reduction-relation: shortcut name may not be a 
> non-terminal in: e_1."
> 
> 
> 
> I believe this was caused by the following change 
> (https://github.com/racket/redex/blob/master/redex-lib/redex/HISTORY.txt) in 
> Redex v6.4:
> 
> 
> 
> changed shortcuts in --> so that non-terminals are no
> 
> longer allowed for the names in the shortcut "parameters"
> 
> These shortcut names were never constrained to actually be
> 
> non-terminals, so this change is intended entirely to be
> 
> able to give a helpful error message in an attempt to avoid
> 
> confusion
> 
> 
> 
> As a Redex novice, I'm failing to avoid confusion in this case. Any advice on 
> a simple way to change the shortcut / reduction relation to respect this 
> change in Redex is greatly appreciated.
> 
> 
> 
> Thanks for the help!
> 
> 
> 
> --
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> 
> 
> 
> 
> 
> 
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Thank you for the relevant group posting... I see, it's an identifier because 
it is in the context of a shortcut. I was mistaking the type of e_1 to be a 
pattern in the context of inner in-hole. Unfortunately, I did not parse 
'shortcut name' in the error message to mean 'shortcut name for an expected 
identifier.' Thanks for the clarification! 

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Re: [racket-users] Redex v6.4 "broke" LambdaJS

[Sam Caldwell]

History behind this change:
https://groups.google.com/d/msg/racket-users/1SVVqsg4ARQ/vVxKiAvaAQAJ
Relevant commit:
https://github.com/racket/redex/commit/cbb2d88b98fb814325f0d4ee468e1abaf4f6c3a7

So changing e_1 and e_2 to be anything that is *not* a non-terminal in your
model should do the trick.

-Sam Caldwell

On Wed, Sep 6, 2017 at 2:39 PM, Ben Greenman 
wrote:

> I think it'll work if you delete the underscores, e.g. change "e_1" to
> "e1".
>
> On Wed, Sep 6, 2017 at 2:22 PM,  wrote:
>
>> (For some reason the mail I sent to usersracket-lang.org last week
>> never made it to the Google Group, so I'm posting directly...)
>>
>> Hello,
>>
>> I'm a 2nd year PhD student working with Shriram Krishnamurthi on
>> improving Redex's testing/checking performance and capabilities.
>>
>> I was looking to use LambdaJS (http://cs.brown.edu/research/
>> plt/dl/jssem/v1/) as a case study, but unfortunately jscore.ss does not
>> compile under the latest version of Redex.
>>
>> The shortcut used in the eval reduction relation
>> ...
>> with
>>[(--> (σ (in-hole E e_1)) (σ (in-hole E e_2)))
>> (==> e_1 e_2)]))
>> now throws an error "reduction-relation: shortcut name may not be a
>> non-terminal in: e_1."
>>
>> I believe this was caused by the following change (
>> https://github.com/racket/redex/blob/master/redex-lib/redex/HISTORY.txt)
>> in Redex v6.4:
>>
>> changed shortcuts in --> so that non-terminals are no
>> longer allowed for the names in the shortcut "parameters"
>> These shortcut names were never constrained to actually be
>> non-terminals, so this change is intended entirely to be
>> able to give a helpful error message in an attempt to avoid
>> confusion
>>
>> As a Redex novice, I'm failing to avoid confusion in this case. Any
>> advice on a simple way to change the shortcut / reduction relation to
>> respect this change in Redex is greatly appreciated.
>>
>> Thanks for the help!
>>
>> --
>> 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.
>>
>
> --
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Re: [racket-users] Redex v6.4 "broke" LambdaJS

[Ben Greenman]

I think it'll work if you delete the underscores, e.g. change "e_1" to "e1".

On Wed, Sep 6, 2017 at 2:22 PM,  wrote:

> (For some reason the mail I sent to usersracket-lang.org last week
> never made it to the Google Group, so I'm posting directly...)
>
> Hello,
>
> I'm a 2nd year PhD student working with Shriram Krishnamurthi on improving
> Redex's testing/checking performance and capabilities.
>
> I was looking to use LambdaJS (http://cs.brown.edu/research/
> plt/dl/jssem/v1/) as a case study, but unfortunately jscore.ss does not
> compile under the latest version of Redex.
>
> The shortcut used in the eval reduction relation
> ...
> with
>[(--> (σ (in-hole E e_1)) (σ (in-hole E e_2)))
> (==> e_1 e_2)]))
> now throws an error "reduction-relation: shortcut name may not be a
> non-terminal in: e_1."
>
> I believe this was caused by the following change (
> https://github.com/racket/redex/blob/master/redex-lib/redex/HISTORY.txt)
> in Redex v6.4:
>
> changed shortcuts in --> so that non-terminals are no
> longer allowed for the names in the shortcut "parameters"
> These shortcut names were never constrained to actually be
> non-terminals, so this change is intended entirely to be
> able to give a helpful error message in an attempt to avoid
> confusion
>
> As a Redex novice, I'm failing to avoid confusion in this case. Any advice
> on a simple way to change the shortcut / reduction relation to respect this
> change in Redex is greatly appreciated.
>
> Thanks for the help!
>
> --
> 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
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[racket-users] Redex v6.4 "broke" LambdaJS

[natasha_danas]

(For some reason the mail I sent to usersracket-lang.org last week never 
made it to the Google Group, so I'm posting directly...)

Hello,

I'm a 2nd year PhD student working with Shriram Krishnamurthi on improving 
Redex's testing/checking performance and capabilities.

I was looking to use LambdaJS (http://cs.brown.edu/research/plt/dl/jssem/v1/) 
as a case study, but unfortunately jscore.ss does not compile under the latest 
version of Redex.

The shortcut used in the eval reduction relation
...
with
   [(--> (σ (in-hole E e_1)) (σ (in-hole E e_2)))
(==> e_1 e_2)]))
now throws an error "reduction-relation: shortcut name may not be a 
non-terminal in: e_1."

I believe this was caused by the following change 
(https://github.com/racket/redex/blob/master/redex-lib/redex/HISTORY.txt) in 
Redex v6.4:

changed shortcuts in --> so that non-terminals are no
longer allowed for the names in the shortcut "parameters"
These shortcut names were never constrained to actually be
non-terminals, so this change is intended entirely to be
able to give a helpful error message in an attempt to avoid
confusion

As a Redex novice, I'm failing to avoid confusion in this case. Any advice on a 
simple way to change the shortcut / reduction relation to respect this change 
in Redex is greatly appreciated.

Thanks for the help!

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[racket-users] Inside Racket Seminar 7. Alexis King on Hackett

[Jay McCarthy]

On September 22nd at 3:30pm Eastern time, please join us for the
seventh Inside Racket Seminar where Alexis King will give us a
walk-through of the Hackett programming language implementation.

As before, it will be on Google Hangouts on Air with Alexis walking
through the code and giving an explanation of how it all hooks
together. This is not a tutorial on Racket or on the library, but a
kind of oral history and explanation of the software and how it works.
Our hope is that this will increase the ability of others to build and
maintain similar software as we share this kind of expertise in a way
that doesn't fit our existing distribution mechanisms (research
papers, RacketCon talks, documentation, etc.)

Link to the stream:
https://www.youtube.com/watch?v=3xFWcNarb3Q

I hope that you are able to attend and send your own questions as we go through.

I have linked some related reading on the Wiki page:

https://github.com/racket/racket/wiki/Inside-Racket-Seminar-7.-Alexis-King-on-Hackett

Please feel free to send questions beforehand, on this thread or to me
personally. We will archive the video for later viewing, etc.

As it turns out, Alexis will also be speaking at RacketCon this year
in a shorter form, so you may consider this a kind of preview for what
is to come there. Check out the rest of the speakers and find
registrations details here:

http://con.racket-lang.org

See you all soon!

-- 
-=[ Jay McCarthy   http://jeapostrophe.github.io]=-
-=[ Associate ProfessorPLT @ CS @ UMass Lowell ]=-
-=[ Moses 1:33: And worlds without number have I created; ]=-

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