[racket-users] big-bang + right click?

[Stephen Foster]

Is there a way to differentiate between left and right click with a 
big-bang on-mouse handler?  Or if not, is there some workaround I can use 
to detect right clicks?

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Re: [racket-users] Does Racket offer anything for implementing a language with its own GC that could manage GPU memory?

[Gustavo Massaccesi]

> Also I forgot to note that I also want my language to have indentation
> sensitive syntax. Would that be doable in Racket?

It's possible (but I never tried it). In the official distribution there
are a few languages implemented in Racket that doesn't look like Racket at
all. For example https://docs.racket-lang.org/algol60/index.html and
https://docs.racket-lang.org/honu/index.html . I also remember a recent
talk by Mathew Flatt about how to implement a non standard language (with
princess and castles ...) but I can't find a link now.

Gustavo


On Sun, Feb 11, 2018 at 2:19 PM, Marko Grdinic  wrote:

> Also I forgot to note that I also want my language to have indentation
> sensitive syntax. Would that be doable in Racket?
>
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[racket-users] Re: Symbolic links and filesystem-change-evt

[George Neuner]

On Wed, 14 Feb 2018 16:35:04 -0600, Philip McGrath
 wrote:

>It appears that a `filesystem-change-evt` created with a path referring to
>a symbolic link effectively watches the target of the link for changes, not
>the link itself. For example, deleting the link and creating a new link
>that points to a different target does not cause the event to become ready
>for synchronization. (I've included a demonstration program at the end of
>this email.)
>
>If this is the expected behavior, it seems like it would be worth
>mentioning in the documentation for `filesystem-change-evt`.
>  :


Changing a symlink should cause a change event on the link's parent
directory.  

As to monitoring the link file itself, I'm not sure that can be done.
AFAICT, Windows and Linux both will transfer a file notify request on
the symlink to be on the target instead.

George

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Re: [racket-users] More DrRacket binding arrow woes

[Matthias Felleisen]

Here is a snippet of code in the language: 

#lang network-flow

;; sample graph

problem: maximize from a to d 

node a -- 10 --> b
node a -- 20 --> c
node b -- 30 --> d
node c -- 30 --> d

Here is a link to the language 

http://www.ccs.neu.edu/home/matthias/4620-s18/network-syn-lang.rkt 


(The github repo for the course is private. Sorry)

— Matthias



> On Feb 15, 2018, at 1:26 AM, Sorawee Porncharoenwase 
>  wrote:
> 
> Thank you for your advice!
> 
> If your code is online and you don't mind, could you point me to the project 
> or any other tutorial so that I can see the sample code? Right now I have 
> https://docs.racket-lang.org/guide/hash-reader.html but the grammar is rather 
> simple. It would be nice if there is a more complex example.
> 
> On Wednesday, February 14, 2018 at 9:32:23 PM UTC-5, Matthias Felleisen wrote:
> 
> Instead of parsing the raw strings, you might consider the following 
> alternative: 
> 
>  — use read tables to nail down identifier syntax and literal constant syntax 
>  — define all keywords and operators and whatever as plain syntax ids that 
> raise a syntax error 
>  — all remaining things are your identifiers  
>  — now use module-begin to turn the sequence of tokens into a tree where each 
> of your identifiers becomes an actual Racket id 
> 
> I just wrote a neat little paren-free language for optmizing network flows 
> this way and it’s a rather viable strategy. 
> 
> 
> 
>> On Feb 14, 2018, at 5:39 AM, Sorawee Porncharoenwase 
>>  wrote:
>> 
>> It works now! I think I simply need a `strip-context` and avoid 
>> `datum->syntax`.
>> 
>> Thank you very much for your help!
>> 
>> On Wednesday, February 14, 2018 at 5:15:06 AM UTC-5, Alexis King wrote:
>> It is worth pointing out that Check Syntax does not see the result of 
>> your reader, it sees the fully-expanded module and performs its analysis 
>> from there. Therefore, it can be useful to use the macro stepper with 
>> macro hiding disabled to inspect the fully-expanded module to make sure 
>> that the information at least appears to be in place. 
>> 
>> In the case of your language, I would use the macro stepper to ensure 
>> the following three things are happening: 
>> 
>>   1. The `sum` identifier appears in binding position in the 
>>  fully-expanded program, and it has the appropriate source location 
>>  information. 
>> 
>>   2. The `sum` identifier also appears in use position in the 
>>  fully-expanded program, and it has distinct source location 
>>  information from the identifier in binding position. 
>> 
>>   3. Both identifiers are syntax-original?. 
>> 
>> If those things are all the case, it’s difficult for me to say much more 
>> without looking at the code itself. 
>> 
>> (As an aside, you should probably be providing the first argument of 
>> my-read-syntax as the first argument to `parse` instead of (object-name 
>> in), but I’m not sure if that’s at all related to the issue here.) 
>> 
>> > On Feb 13, 2018, at 23:33, Sorawee Porncharoenwase 
>> >  wrote: 
>> > 
>> > I have a similar problem but I can't figure out a way to fix it yet 
>> > :( 
>> > 
>> > So, when I hover on `sum` on line 3, I get "no bound occurrences". 
>> > That's definitely false since the program runs fine, and `sum` has a 
>> > bound occurrence below (e.g., line 5). 
>> > 
>> > I print the syntax objects passed into `#%module-begin` in the REPL. 
>> > The srcloc seems right to me. 
>> > 
>> > What baffles me further is that when I follow Robby's suggestion to 
>> > insert a printf inside check-syntax code: 
>> > 
>> > (printf "~a ~a ~a\n" stx-obj (syntax-source stx-obj) (syntax-line 
>> > stx-obj)) 
>> > 
>> > I get the following result (only relevant lines shown) 
>> > 
>> > # #f #f 
>> > # #f #f 
>> > # string 3 
>> > # string 3 
>> > # #f #f 
>> > # string 3 
>> > # #f #f 
>> > # string 5 
>> > # #f #f 
>> > # #f #f 
>> > # string 7 
>> > # string 7 
>> > # string 7 
>> > # #f #f 
>> > # string 7 
>> > ... 
>> > 
>> > So: the sum on line 3 is either missing or somehow becomes `#> > temp1> #f #f` 
>> > 
>> > And sum on line 7 has a correct srcloc, except that the syntax-source 
>> > somehow changes from `'unsaved-editor` to `string`?!? 
>> > 
>> > FYI, I use megaparsack's `parse-syntax-string` like this: 
>> > 
>> > (define (parse src in) 
>> >   (define len (string-length "#lang recursive-language")) 
>> >   (parse-result! 
>> >(parse-syntax-string toplevel/p 
>> > (datum->syntax #f (port->string in) 
>> >(list src 1 len (add1 len) 0 
>> > 
>> > And this is my module reader 
>> > 
>> > (module reader racket 
>> >   (require syntax/strip-context) 
>> >   (require "parser.rkt") 
>> >   (provide (rename-out [my-read-syntax read-syntax] 
>> >[my-read