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Show HN: Céu, Structured Synchronous Reactive Programming

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Re: Show HN: Céu, Structured Synchronous Reactive Programming

#31

Post by AlexanderDhoore »

fsantanna wrote: post #30
AlexanderDhoore wrote: post #29

I've been trying to learn more about synchronous programming languages for a while now. Will definitely look into this. Does anyone know how I could get my hands on Lustre or Esterel? They are not freely available, or are they? Also any good books or resources are very much appreciated.

You can download Esterel freely: http://www-sop.inria.fr/esterel-org/files/Html/Downloads/Dow... (AFAIK, it is not open source though.) [EDIT] For documentation, see "The Esterel Language Primer": http://www.rw.cdl.uni-saarland.de/~kaestner/es0203/esterel_p... Don't know about Lustre.

Thank you! I'm actually working on my own synchronous language, but it's more in line with Lustre than Esterel. Synchronous dataflow with soft real-time goals. If it starts to look like something decent I'll put it on github.

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#32

Post by ratstew »

AlexanderDhoore wrote: post #31
fsantanna wrote: post #30

Earlier quoted context omitted.

You can download Esterel freely: http://www-sop.inria.fr/esterel-org/files/Html/Downloads/Dow... (AFAIK, it is not open source though.) [EDIT] For documentation, see "The Esterel Language Primer": http://www.rw.cdl.uni-saarland.de/~kaestner/es0203/esterel_p... Don't know about Lustre.

Thank you! I'm actually working on my own synchronous language, but it's more in line with Lustre than Esterel. Synchronous dataflow with soft real-time goals. If it starts to look like something decent I'll put it on github.

Since you're interested in the implementation of synchronous languages you could also take a look at Quartz [1]. Their book is a fantastic resource about the topic.

[1] http://www.averest.org

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#34

Post by tluyben2 »

fsantanna wrote: post #2

Hi, I'm the author of the programming language Céu. Although Céu is about 5 years now, this is the first time I post to "Show HN". In this new version, we are trying to surpass the academic fences with a more polished work (docs, build, etc). All feedback is welcome. Francisco

Thanks for posting it. And for sticking with it that long. It is something I will one time do but I did not try enough languages yet to forge my own.

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#35

Post by jessaustin »

fsantanna wrote: post #8
teleclimber wrote: post #7

Earlier quoted context omitted.

It would be helpful if you could provide a high-level explanation of what "Structured Reactive Programming" means and what problem you are trying to solve with current solutions? How is it different from current reactive environments?

Thank you, I will improve the page. In summary: Reactive: code executes in reactions to events Synchronous: reactions run to completion, i.e., there's no implicit preemption or real parallelism (this avoids explicit synchronization: locks, queues, etc) Structured: programs use structured control mechanisms, such as "await" (to suspend a line of execution), and "par" (to combine multiple awaiting lines of execution) S…

Synchronous: reactions run to completion, i.e., there's no implicit preemption or real parallelism

Does this mean a program will hang if e.g. disk or network access takes too long?

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#36

Post by hisham_hm »

jessaustin wrote: post #35
fsantanna wrote: post #8

Earlier quoted context omitted.

Thank you, I will improve the page. In summary: Reactive: code executes in reactions to events Synchronous: reactions run to completion, i.e., there's no implicit preemption or real parallelism (this avoids explicit synchronization: locks, queues, etc) Structured: programs use structured control mechanisms, such as "await" (to suspend a line of execution), and "par" (to combine multiple awaiting lines of execution) S…

Synchronous: reactions run to completion, i.e., there's no implicit preemption or real parallelism Does this mean a program will hang if e.g. disk or network access takes too long?

Yes in theory. But in practice the language includes "async" support so you can guard these few operations that may take long. Like in a functional language you assume everything is pure unless marked to have side-effects, here you assume every reaction is instant unless is something that has to be explicitly "awaited" for. It's a pretty clean model.

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#37

Post by agumonkey »

fsantanna wrote: post #2

Hi, I'm the author of the programming language Céu. Although Céu is about 5 years now, this is the first time I post to "Show HN". In this new version, we are trying to surpass the academic fences with a more polished work (docs, build, etc). All feedback is welcome. Francisco

What were your influences ? other "synchronous" languages like lucid ?

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#38

Post by fsantanna »

agumonkey wrote: post #37
fsantanna wrote: post #2

Hi, I'm the author of the programming language Céu. Although Céu is about 5 years now, this is the first time I post to "Show HN". In this new version, we are trying to surpass the academic fences with a more polished work (docs, build, etc). All feedback is welcome. Francisco

What were your influences ? other "synchronous" languages like lucid ?

The main influence is Esterel, but we visited most synchronous literature (including Lucid).

We also take the syntax from Pascal/Lua and the basic types and expressions from C (due to source compatibility).

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#39

Post by agumonkey »

fsantanna wrote: post #38
agumonkey wrote: post #37

Earlier quoted context omitted.

What were your influences ? other "synchronous" languages like lucid ?

The main influence is Esterel, but we visited most synchronous literature (including Lucid). We also take the syntax from Pascal/Lua and the basic types and expressions from C (due to source compatibility).

Thanks a lot. We had a class in esterel in college, but it flew over my head at the time, sadly. Time to revisit the whole thing.

May I ask you if you have some favorite references/papers about the subject ?

Re: Show HN: Céu, Structured Synchronous Reactive Programming

#40

Post by fsantanna »

jessaustin wrote: post #35
fsantanna wrote: post #8

Earlier quoted context omitted.

Thank you, I will improve the page. In summary: Reactive: code executes in reactions to events Synchronous: reactions run to completion, i.e., there's no implicit preemption or real parallelism (this avoids explicit synchronization: locks, queues, etc) Structured: programs use structured control mechanisms, such as "await" (to suspend a line of execution), and "par" (to combine multiple awaiting lines of execution) S…

Synchronous: reactions run to completion, i.e., there's no implicit preemption or real parallelism Does this mean a program will hang if e.g. disk or network access takes too long?

External calls in C require an underscore (e.g., "_printf") to be easily trackable as possibly unsafe.

Also, at some point in the code (e.g., after you include your libraries), one can disable these calls with a directive.

But typically, one will use bindings for asynchronous libraries, such as libuv (https://github.com/fsantanna/ceu-libuv).

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