[racket-users] reporting contract violations in executable programs

2018-11-01 Thread Alexander McLin
I’m a little confused here, to me it looks like the second contract violation is completely different from the first one. You were expecting `foo` to raise a contract violation but in your executable example it appears that contract violation is being raised by the `build-path` function not

Re: [racket-users] How to tighten the contract on a function

2018-09-05 Thread Alexander McLin
Something like the following program: #lang racket (module foomod racket (provide foo) (define/contract (foo arg) (-> string? #t) #t)) (require 'foomod) (provide (contract-out (foo (-> non-empty-string? #t On Tuesday, September 4, 2018 at 9:00:06 PM UTC-4, David K. Storrs wrote: > >

Re: [racket-users] How to tighten the contract on a function

2018-09-05 Thread Alexander McLin
What about reproviding foo and using contract-out to wrap foo in a new contract? On Tuesday, September 4, 2018 at 9:00:06 PM UTC-4, David K. Storrs wrote: > > > > On Tue, Sep 4, 2018 at 8:55 PM, Matthew Butterick > wrote: > >> >> On Sep 4, 2018, at 3:54 PM, David Storrs > > wrote: >> >> Say

[racket-users] Re: Recommendation for learning syntax?

2018-08-07 Thread Alexander McLin
I was an attendee of Racket Summer School 2018 where we covered syntax-parse extensively. The lecture plans and problem assignments are still available online and they together comprise a good tutorial for syntax-parse and language design principles. I encourage you to give it a try!

Re: [racket-users] Unicode identifiers

2018-05-16 Thread Alexander McLin
Would it be possible to adjust the readtable to replace "→" with "->" ? On Wednesday, May 16, 2018 at 10:32:43 AM UTC-4, Andrew Kent wrote: > > `racket/string` needs to be required _for syntax_ in order to work in the > suggested way (because it's bindings are needed at compile time). > > The

[racket-users] Re: error in DrRacket but not in script

2018-04-10 Thread Alexander McLin
My guess the problem is (define imleftname #"./tsukubaleft.jpg") You're using a relative path to the jpg file which may be valid wherever your script file is located but DrRacket is probably starting up with a different working directory and the relative path is not resolving successfully.

Re: [racket-users] Struct general question

2018-03-30 Thread Alexander McLin
As an aside, vectors are intended to be a constant-time access data structure. Lists aren't so it won't make sense to build vectors on top of lists which would make for non-constant slot access times. On Monday, March 26, 2018 at 4:13:02 PM UTC-4, lysseus wrote: > > > > > On Mar 26, 2018, at

Re: [racket-users] racket (7) on a new arch

2018-02-23 Thread Alexander McLin
On Friday, February 23, 2018 at 11:08:23 AM UTC-5, David K. Storrs wrote: > > > On Thu, Feb 22, 2018 at 11:14 AM, Alexander McLin <alex@gmail.com > > wrote: > >> As one of those who have been following RISC-V progress for several years >> and also interes

Re: [racket-users] racket (7) on a new arch

2018-02-22 Thread Alexander McLin
As one of those who have been following RISC-V progress for several years and also interested in seeing Racket being ported to that architecture I want to drop a note to let you know you have my support! -- You received this message because you are subscribed to the Google Groups "Racket

Re: [racket-users] Adding interactive overlays to racket plots

2018-02-04 Thread Alexander McLin
Your interactive plot looks wonderful and would be a good replacement for some of R's statistical graphing features. I'm excited you're making this valuable contribution to Racket. I did noticed something in your documentation at

[racket-users] Re: Reliably propagating received log messages to ports

2018-02-01 Thread Alexander McLin
Thanks all for your inputs. I tried `with-intercepted-logged` before though it didn't solve all of my issues, though as Robby mentioned, my code probably isn't accurately capturing all of the start and exit nuances my need reflect, I'll need to think more about the big picture to do a better

[racket-users] Reliably propagating received log messages to ports

2018-01-31 Thread Alexander McLin
Thank you for your suggestions. Alexander McLin -- 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 opti

[racket-users] Re: How to integrate Racket with a .Net application?

2018-01-31 Thread Alexander McLin
All three approaches you outlined are viable but web service is easiest to set up. >From what you described, it seems it would be a low-performance use for Racket and only simple data structures will be passed back and forth on an infrequent basis. Web service would be a good fit for that.

Re: [racket-users] Equivalent of dynamic-wind post-thunk for with-handlers

2018-01-24 Thread Alexander McLin
On Wednesday, January 24, 2018 at 5:54:44 PM UTC-5, Alexis King wrote: > > Based on your question, why not just use dynamic-wind in combination > with with-handlers? Just keep in mind that the post-thunk could be > called multiple times if there is a continuation jump into value-thunk, > so

[racket-users] Equivalent of dynamic-wind post-thunk for with-handlers

2018-01-24 Thread Alexander McLin
I have a with-handlers expression which handles several exceptions appropriately and raises user-error exceptions, I have some additional code I'd like to be executed after the exception have been handled, analogous to dyanmic-wind's post-thunk argument or like the finally clause of a

[racket-users] Re: Installing Racket Package `gregor` inside a Docker container

2017-12-27 Thread Alexander McLin
I don't have much to add but wanted to note that the problem appears to be in rendering grengor's documentation. The package itself may be installed fine, just not its associated documentation. You can test to verify if package is installed by querying via raco pkg or just requiring gregor in a

[racket-users] Re: New package: Argo: JSON Schema validation

2017-08-30 Thread Alexander McLin
This is quite a timely post. I had been looking into using a JSON schema validation C library and using FFI to hook into that for my projects. I'll give your new package a try! Thank you for making it available Jesse. -- You received this message because you are subscribed to the Google

[racket-users] Re: query-exec SQLite3 multiple statements

2017-07-28 Thread Alexander McLin
Yes, you can use DrRacket to debug the file at collects/db/private/sqlite3/connection.rkt. That one is likely the most relevant one for you. Alternatively, you could wait till Racket 6.10 is released which is very soon I think. The bug fixes to the db library might reveal the correct error

[racket-users] Re: query-exec SQLite3 multiple statements

2017-07-26 Thread Alexander McLin
I tried query-exec on those SQL strings you posted on gist on my local copy of Racket 6.8 with an in-memory SQLite3 db and it worked fine. I'm not sure what's causing your issue. What version of Racket and SQLite3 are you running on your machine? Is it Windows, Linux, or Mac OSX? >

[racket-users] Re: query-exec SQLite3 multiple statements

2017-07-26 Thread Alexander McLin
One more thing for you to check, make sure there's no trailing whitespace after the end of your statement's terminating semi-colon, that will also trigger the `multiple statements given` error. That bug has been also fixed in the current repository. -- You received this message because you

[racket-users] Re: query-exec SQLite3 multiple statements

2017-07-26 Thread Alexander McLin
It appears you're giving to `query-exec` a string consisting of two statements; the create table and insert into statements. `query-exec` only supports executing one statement at a time. If you break your two statements up into two strings and call `query-exec` on each one, it should work. --

[racket-users] Re: Searching diffrences in two lists

2017-06-28 Thread Alexander McLin
Consider using the following function https://docs.racket-lang.org/reference/pairs.html?q=memq#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._memq%29%29 It's helpful to sketch out the general steps you'd need to be able to carry out the procedure to solve the problem. My quick sketch

[racket-users] Re: inspecting a table error 'error 'query: multiple statements given'

2017-06-25 Thread Alexander McLin
FYI, the misleading "multiple statements given" error has been fixed in the racket master branch and correct syntax error message is now being raised. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop

[racket-users] Re: Executing batch statements against a database using `db` library.

2017-05-12 Thread Alexander McLin
Thank you Alex, your code looks comprehensive and ought cover my use case. Appreciate your sharing! Best, Alexander -- 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

[racket-users] Executing batch statements against a database using `db` library.

2017-05-12 Thread Alexander McLin
`db` library doesn't seem to provide support for executing batch statements against a database. I'm trying to initialize and create an in-memory SQLite3 database using a SQL schema file. `query-exec` and its friends only support executing single SQL statements. Reading documentation isn't

[racket-users] Re: Racket Package Catalog Site and Raco Commands

2017-04-24 Thread Alexander McLin
While I have no strong preferences for whether it would be better to allow end-users determine what tags to apply as opposed to automatic system tags, it might be more effective to make provisions for special tags to be supported in info.rkt and have the catalog automatically read those tags if

[racket-users] Re: Racket Package Catalog Site and Raco Commands

2017-04-24 Thread Alexander McLin
All of your suggestions are great and get my vote. To elaborate on the raco tag, it should list all the commands *and* subcommands. Example: pkg package tag: raco: pkg install, pkg update, pkg remove, etc. -- You received this message because you are subscribed to the Google Groups "Racket

[racket-users] Racket Package Catalog Site and Raco Commands

2017-04-24 Thread Alexander McLin
First of all, I wish to express my appreciation for such a beautifully designed package catalog site located at pkgs.racket-lang.org. I was wondering if we could add a special search term category or tag that list all available raco commands that packages may install? For example, when

Re: [racket-users] Announcing Leibniz, a new language in the Racket universe

2017-04-20 Thread Alexander McLin
> Indeed. What would be such classical papers from your field? One paper I have in mind is Hodgkin & Huxley's paper published in 1952 where they first wrote down the equations describing the membrane voltage of the giant squid axon.

[racket-users] Re: [Shameless self-promotion] Articles about programming-language theory for working programmers in Racket

2017-04-17 Thread Alexander McLin
Leandro, Your article comes at a good time for me because I received my copy of "Semantics Engineering with PLT Redex" last week and am preparing to start studying it. I thought your examples are a nice exposition of the complex ideas that go into selecting features a programming language

[racket-users] Re: inspecting a table error 'error 'query: multiple statements given'

2017-04-17 Thread Alexander McLin
The error message is unclear but I believe SQLite do not support parameters for PRAGMA statements. The SQLite documentation at http://www.sqlite.org/lang_expr.html#varparam specifically says parameters are supported by expressions. PRAGMA statements are not expressions. If you examine the

Re: [racket-users] Announcing Leibniz, a new language in the Racket universe

2017-04-16 Thread Alexander McLin
This looks quite promising, I'm liking the progress and examples so far. The idea of using the same notation to express both equations and algorithms excites me. It would certainly make it easier to write down and analyze algorithms implementing a set of model equations in a language

[racket-users] Re: linking with raco ctool : unable to find libracket3mxxxxxxx.lib

2017-03-14 Thread Alexander McLin
You need to compile Racket from source to generate the .lib file, it is not distributed with the installation. You need to make sure the source is the same version as your installed Racket and it is compiled targeting the same bit architecture as the installed Racket version. Then copy the

Re: [racket-users] Request for Information about Racket and .NET interop support

2017-01-16 Thread Alexander McLin
I understand where you're coming from. My organization is flexible and isn't ideologically committed to one particular platform. Microsoft's community promise is just that, a promise. It can be changed or revoked at any time in the future. I've been encouraging adoption of open system

Re: [racket-users] Request for Information about Racket and .NET interop support

2017-01-16 Thread Alexander McLin
Thank you Matthias for the historical information, it was interesting to learn that a porting project was sponsored by Microsoft in .NET's early days. Were any papers describing the efforts published? Porting Racket to .NET definitely is ambitious and as you have said, it seems unlikely .NET

[racket-users] Request for Information about Racket and .NET interop support

2017-01-15 Thread Alexander McLin
much welcome. Best, Alexander McLin -- 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, v

Re: [racket-users] Re: racket users fight for their right to colon keywords

2015-11-24 Thread Alexander McLin
I remember those classes as a student, to be honest I didn't really actually started to learn till after I'd left undergraduate. Don't get me wrong, I know how frustrating syntax/semantics nuances can be. I've been reflecting on the idea of existential keywords the past couple days and have

[racket-users] Re: racket users fight for their right to colon keywords

2015-11-22 Thread Alexander McLin
in the keyword grammar when all other keyword cases are allowed to assume arbitrary values. Aλexander On Sunday, November 22, 2015 at 12:08:49 PM UTC-5, Alexander McLin wrote: > I don't really have a horse in this race. My position is very similar to > Alexis which is why I didn'

[racket-users] Re: racket users fight for their right to colon keywords

2015-11-22 Thread Alexander McLin
I don't really have a horse in this race. My position is very similar to Alexis which is why I didn't vote in the poll too. When I first arrived to Racket the #: syntax made me go "what in the world?" Since then I've grown to appreciate the reasoning behind the deliberate eye catching keyword

[racket-users] Re: Gear VR

2015-07-01 Thread Alexander McLin
On Wednesday, July 1, 2015 at 7:07:03 AM UTC-4, AJ Campbell wrote: JSON is probably going to be the go-to format to send/receive renderable 3D packets. The thought of doing it with XML makes me feel ill. I'm sure Racket can handle JSON data (it very well might already for all I know), but