Re: [racket-users] Reliably propagating received log messages to ports
On 1/31/2018 5:00 PM, Alexander McLin wrote: During the tool's start up period prior to calling the main function I set up a log receiver to receive messages at the desired level and place it inside a sync loop within its own thread. Each time a sync event is received, it is written out to the port, then loop back to waiting for the next sync event. It works reasonably well except I have a new problem, when the tool exits, it often exits before the thread handling the log receiver propagation to the port has finished receiving all the log events, as a result my logging output is frequently truncated. Given this undesired situation, I need to figure out a better way to reliably propagate all log messages to ports before the tool exits normally or due to a raised exception. There may be a better way, but I handle this kind of thing with dynamic-wind. The program's main function looks like (start : (dynamic-wind (lambda () ;;; startup services ... ) (lambda () ;;; program's purpose ... ) (lambda () ;;;shutdown services ... ) ) : ) There is `with-logging-to-port` except I will need to set up multiple ports and the idea of wrapping the tool's main body with multiple `with-logging-to-port` for each port isn't appealing and it still doesn't resolve the problem. I use with-logging-to-port in the individual logger threads to direct their output. I don't wrap it around all the code. I was wondering if anyone has a better suggestion? Is there a way to detect if there are pending log events waiting to be received by the log receiver? Not that I know of, but if you structure the logger so that it must be specifically shut down, you can drain the message queue before terminating. 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. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Datalog Question
Something like kevin(Y) :- foo(x, Y), Y != 3. kevin(Y)? On Wed, Jan 31, 2018 at 5:13 PM, Kevin Forchione wrote: > Can anyone tell me how I would use the datalog = and != tokens? The > documentation says they can separate terms, such as != . In the > program below, how would I create a query for foo(x, ?) where ? is not 3? > > #lang datalog > > foo(bil, 1). > foo(bob, 3). > foo(joe, 2). > > I imagine I’d have to create a rule of some sort. > > -Kevin > > -- > 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]=- -=[ Associate ProfessorPLT @ CS @ UMass Lowell ]=- -=[ Moses 1:33: And worlds without number have I created; ]=- -- 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.
[racket-users] Datalog Question
Can anyone tell me how I would use the datalog = and != tokens? The documentation says they can separate terms, such as != . In the program below, how would I create a query for foo(x, ?) where ? is not 3? #lang datalog foo(bil, 1). foo(bob, 3). foo(joe, 2). I imagine I’d have to create a rule of some sort. -Kevin -- 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] Reliably propagating received log messages to ports
I think the right approach here is to recognize that you have a more complex protocol than is currently reflected in your code and dive into Racket's evt support. In this particular case, I suggest you make a new channel that the loop in the thread also listens on, If yet another channel comes in on that one, you flush all pending messages and then send a message back saying "I'm done". Then the code that catches the exit can use that mechanism to communicate "I'm about to exit, please finish up". Robby On Wed, Jan 31, 2018 at 4:00 PM, Alexander McLin wrote: > So I am using Racket's logging facilities in a command-line tool I'm > developing. I have various defined loggers in a sensible hierarchical > configuration for use as needed. > > During the tool's start up period prior to calling the main function I set > up a log receiver to receive messages at the desired level and place it > inside a sync loop within its own thread. Each time a sync event is > received, it is written out to the port, then loop back to waiting for the > next sync event. > > It works reasonably well except I have a new problem, when the tool exits, > it often exits before the thread handling the log receiver propagation to > the port has finished receiving all the log events, as a result my logging > output is frequently truncated. > > Given this undesired situation, I need to figure out a better way to > reliably propagate all log messages to ports before the tool exits normally > or due to a raised exception. > > There is `with-logging-to-port` except I will need to set up multiple ports > and the idea of wrapping the tool's main body with multiple > `with-logging-to-port` for each port isn't appealing and it still doesn't > resolve the problem. > > I was wondering if anyone has a better suggestion? Is there a way to detect > if there are pending log events waiting to be received by the log receiver? > > I realize the fundamental nature of my issue is that Racket's logging is > asynchronous while I want synchronous behavior. I may be better off just > using old-fashioned `println`s > > 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 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] Reliably propagating received log messages to ports
Does `with-intercepted-logging` do what you want? It should take care of the sychronization aspects, like `with-logging-to-port` does, while letting you do whatever you want with the message, e.g., sending them to different ports. Vincent On Wed, 31 Jan 2018 16:00:58 -0600, Alexander McLin wrote: > > So I am using Racket's logging facilities in a command-line tool I'm > developing. I have various defined loggers in a sensible hierarchical > configuration for use as needed. > > During the tool's start up period prior to calling the main function I set up > a log receiver to receive messages at the desired level and place it inside a > sync loop within its own thread. Each time a sync event is received, it is > written out to the port, then > loop back to waiting for the next sync event. > > It works reasonably well except I have a new problem, when the tool exits, it > often exits before the thread handling the log receiver propagation to the > port has finished receiving all the log events, as a result my logging output > is frequently truncated. > > Given this undesired situation, I need to figure out a better way to reliably > propagate all log messages to ports before the tool exits normally or due to > a raised exception. > > There is `with-logging-to-port` except I will need to set up multiple ports > and the idea of wrapping the tool's main body with multiple > `with-logging-to-port` for each port isn't appealing and it still doesn't > resolve the problem. > > I was wondering if anyone has a better suggestion? Is there a way to detect > if there are pending log events waiting to be received by the log receiver? > > I realize the fundamental nature of my issue is that Racket's logging is > asynchronous while I want synchronous behavior. I may be better off just > using old-fashioned `println`s > > 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 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.
[racket-users] Reliably propagating received log messages to ports
So I am using Racket's logging facilities in a command-line tool I'm developing. I have various defined loggers in a sensible hierarchical configuration for use as needed. During the tool's start up period prior to calling the main function I set up a log receiver to receive messages at the desired level and place it inside a sync loop within its own thread. Each time a sync event is received, it is written out to the port, then loop back to waiting for the next sync event. It works reasonably well except I have a new problem, when the tool exits, it often exits before the thread handling the log receiver propagation to the port has finished receiving all the log events, as a result my logging output is frequently truncated. Given this undesired situation, I need to figure out a better way to reliably propagate all log messages to ports before the tool exits normally or due to a raised exception. There is `with-logging-to-port` except I will need to set up multiple ports and the idea of wrapping the tool's main body with multiple `with-logging-to-port` for each port isn't appealing and it still doesn't resolve the problem. I was wondering if anyone has a better suggestion? Is there a way to detect if there are pending log events waiting to be received by the log receiver? I realize the fundamental nature of my issue is that Racket's logging is asynchronous while I want synchronous behavior. I may be better off just using old-fashioned `println`s 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 options, visit https://groups.google.com/d/optout.
Re: [racket-users] Apparent Datalog error?
On 1/31/2018 2:51 PM, Matthias Felleisen wrote: > On Jan 31, 2018, at 2:15 PM, George Neuner wrote: > > > On 1/31/2018 2:10 PM, Sam Caldwell wrote: >> Your definition of `ancestor` is one or two steps of parentage: >> >> > ancestor(A, B) :- parent(A, B). >> > ancestor(A, B) :- >> parent(A, C), >> parent(C, B). >> >> I suspect you want one of those lines to appeal to the `ancestor` relation to allow longer chains. > > Knowing nothing about datalog he asks naively: > > Shouldn't the ruleancestor(A, B) :- parent(A, C), parent(C, B). be applied recursively? It is — except that there’s no recursion. > Kevin's definition would work in Prolog. No it wouldn’t. Sorry ... brain freeze. Somehow I misread Kevin's code as being ancestor(A, B) :- parent(A, C), ancestor(C, B). which would work. You and Sam both are absolutely correct that it does not work as written. Apologies for the noise. 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. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Apparent Datalog error?
> On Jan 31, 2018, at 2:15 PM, George Neuner wrote: > > > On 1/31/2018 2:10 PM, Sam Caldwell wrote: >> Your definition of `ancestor` is one or two steps of parentage: >> >> > ancestor(A, B) :- parent(A, B). >> > ancestor(A, B) :- >> parent(A, C), >> parent(C, B). >> >> I suspect you want one of those lines to appeal to the `ancestor` relation >> to allow longer chains. > > Knowing nothing about datalog he asks naively: > > Shouldn't the ruleancestor(A, B) :- parent(A, C), parent(C, B). be > applied recursively? It is — except that there’s no recursion. > Kevin's definition would work in Prolog. No it wouldn’t. -- 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] Apparent Datalog error?
On 1/31/2018 2:10 PM, Sam Caldwell wrote: Your definition of `ancestor` is one or two steps of parentage: > ancestor(A, B) :- parent(A, B). > ancestor(A, B) :- parent(A, C), parent(C, B). I suspect you want one of those lines to appeal to the `ancestor` relation to allow longer chains. Knowing nothing about datalog he asks naively: Shouldn't the rule ancestor(A, B) :- parent(A, C), parent(C, B). be applied recursively? Kevin's definition would work in Prolog. 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. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Apparent Datalog error?
Your definition of `ancestor` is one or two steps of parentage: > ancestor(A, B) :- parent(A, B). > ancestor(A, B) :- parent(A, C), parent(C, B). I suspect you want one of those lines to appeal to the `ancestor` relation to allow longer chains. - Sam Caldwell On Wed, Jan 31, 2018 at 1:53 PM, Kevin Forchione wrote: > Walking through the datalog tutorial I got the following transcript: > > Welcome to DrRacket, version 6.12 [3m]. > Language: datalog, with debugging; memory limit: 512 MB. > > parent(john, douglas). > > parent(john, douglas)? > parent(john, douglas). > > parent(john, evlyn)? > > > parent(bob, john). > > parent(A, B)? > parent(john, douglas). > parent(bob, john). > > parent(ebbon, bob). > > parent(john, B)? > parent(john, douglas). > > parent(A, A)? > > > ancestor(A, B) :- parent(A, B). > > ancestor(A, B) :- > parent(A, C), > parent(C, B). > > ancestor(A, B)? > ancestor(ebbon, bob). > ancestor(bob, john). > ancestor(john, douglas). > ancestor(bob, douglas). > ancestor(ebbon, john). > > > > It seems that the correct answer should also include ancestor(ebbon, > douglas). Am I doing something wrong? > > -Kevin > > > -- > 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.
[racket-users] Apparent Datalog error?
Walking through the datalog tutorial I got the following transcript: Welcome to DrRacket, version 6.12 [3m]. Language: datalog, with debugging; memory limit: 512 MB. > parent(john, douglas). > parent(john, douglas)? parent(john, douglas). > parent(john, evlyn)? > parent(bob, john). > parent(A, B)? parent(john, douglas). parent(bob, john). > parent(ebbon, bob). > parent(john, B)? parent(john, douglas). > parent(A, A)? > ancestor(A, B) :- parent(A, B). > ancestor(A, B) :- parent(A, C), parent(C, B). > ancestor(A, B)? ancestor(ebbon, bob). ancestor(bob, john). ancestor(john, douglas). ancestor(bob, douglas). ancestor(ebbon, john). > It seems that the correct answer should also include ancestor(ebbon, douglas). Am I doing something wrong? -Kevin -- 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] How to integrate Racket with a .Net application?
Another way is for two (OS) processes to "pipe" I/O to each other. The back-and-forth "protocol"? It could be as simple/ad-hoc vs. as formal/ceremonial as you prefer. It could be text line-oriented, or JSON, or s-expressions, or raw bytes. I might use this as a starting point, get some mileage, then decide if it's adequate or what to do instead. p.s. If you squint and abstract away certain details, this is similar to the HTTP service approach. -- 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.
[racket-users] Re: How to integrate Racket with a .Net application?
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. Out of the last two approaches, the COM approach seems to me to be the better one. Although I have never used it, Racket provides MzCOM and .NET comes with additional support for interacting with COM from within the .NET environment. It would allow you to tightly integrate Racket into your application, pass complex data back and forth and achieve higher performance throughout, but likely it would be more work. I've used COM in the past for C++ applications; in those projects it was always a lot of work to configure and integrate COM. I would try setting up a web service first and if it's not adequate for whatever reason (performance, business requirements, etc) then I would try the COM approach. -- 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.
[racket-users] How to integrate Racket with a .Net application?
Hello: We have an application on Windows that can be extended with .Net components (DLL). We mostly use C# for this purpose. Our idea now is to "embed" Racket into one of these components. After reading the documentation of the FFI and de C API I am unsure what may a good way to accomplish that. Has anybody done something like this or has an implementation idea? We want to push some basic data (lists of structs, strings, numbers etc.) to a Racket component, trigger some functions and get some result back. This action is triggered by user input once in several days. There are several ways I am thinking about: - establish some sort of web service (talking JSON over HTTP) - use the C API - use the libraries for COM objects Any advice or ideas would be greatly appreciated! Best wishes, Daniel -- 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.
