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How I want to write Node: Stream all the things

caolanmcmahon.com

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Re: How I want to write Node: Stream all the things

#71

Post by gruseom »

delluminatus wrote: post #66
gruseom wrote: post #61

Earlier quoted context omitted.

I have a question about the async library: what does it do if an asynchronous function or a callback raises an exception? The word "catch" doesn't appear in https://github.com/caolan/async/blob/master/lib/async.js . I ask because I wrote some Lisp macros (I work in a Lisp that compiles to JS) to implement a few async patterns I need, and making sure that exceptions are trapped and threaded into the callback chain cor…

Last I checked, exceptions were not widely used in javascript because the try... catch block was a huge performance loss. I forget why exactly -- I want to say that the browser would spin up a whole new interpreter for catch blocks, just like with eval -- and it might be fixed in more modern JS engines, but I've still never seen exceptions used in JS. So I wouldn't be surprised if async doesn't handle them at all.

But runtime errors are exceptions, so even if your code doesn't throw them, you have this problem. No?

Re: How I want to write Node: Stream all the things

#72

Post by kimjotki2 »

It looks like this whole notion of 'stream' is just a syntactic sugar for javascript guys who lost themselves in a bunch of nested stupid callbacks, which is worse than lisp parens. Instead of nesting whole callbacks, create a stream in the middle; execute first half of callback chain and dump the result into the stream so that next half of callback chain can be executed later.

Why is this so an enlightenment for node guys? UNIX does it right since epoch - simple programs perform simple tasks and connected via pipes. Python has gevent, so you don't even need 'a stream' or other bullshit, you just write the code as-is and greenlets provide the concurrency needed.

The real enlightenment comes from 'programming properly'; you start with C and torture your brain with function pointers and realize why it is a good idea to treat functions as a first-class objects. then you learn some 'proper' functional programming languages like lisp or something to learn how to think in functional way. which is the only guaranteed and proven path to prevent yourself from shooting your own foot by writing 20+ nested callbacks. If you start with binding an anonymous function to a 's click event and think you can do this to do real programming, you'll never get it right.

Re: How I want to write Node: Stream all the things

#73

Post by woah »

kimjotki2 wrote: post #72

It looks like this whole notion of 'stream' is just a syntactic sugar for javascript guys who lost themselves in a bunch of nested stupid callbacks, which is worse than lisp parens. Instead of nesting whole callbacks, create a stream in the middle; execute first half of callback chain and dump the result into the stream so that next half of callback chain can be executed later. Why is this so an enlightenment for nod…

Wise words of wisdom from kimjotki2, the only real programmer on the internet. Bow down, bitches.

Re: How I want to write Node: Stream all the things

#74

Post by woah »

gruseom wrote: post #71
delluminatus wrote: post #66

Earlier quoted context omitted.

Last I checked, exceptions were not widely used in javascript because the try... catch block was a huge performance loss. I forget why exactly -- I want to say that the browser would spin up a whole new interpreter for catch blocks, just like with eval -- and it might be fixed in more modern JS engines, but I've still never seen exceptions used in JS. So I wouldn't be surprised if async doesn't handle them at all.

But runtime errors are exceptions, so even if your code doesn't throw them, you have this problem. No?

You generally pass expected errors up the chain, exceptions are for things like syntax and type errors etc, that only happen if you have coded it wrong. I run the server on forever.js, then go back in and fix my mistakes if that happens.

Re: How I want to write Node: Stream all the things

#75

Post by woah »

spion wrote: post #47
nailer wrote: post #43

Earlier quoted context omitted.

- Why BlueBird? What's wrong with Q? - Isn't data a scope down? - https://github.com/petkaantonov/bluebird/blob/master/API.md is API based, not task based. async is API based too, but the API has names like 'waterfall' and 'parallel'. I can click them because I know what they mean. Promises just makes me feel like I'm reading about and endless series of abstractions.

There is nothing wrong with Q, but Bluebird is a bit more node-oriented and also has really, really low CPU/memory overhead (lower than caolan's async). Also it provides the best debugging experience, period - because of its long stack traces spanning multiple previous async events. I didn't quite understand the comment about data being a scope down. What do you mean? Yes, promises do have quite a steep learning curv…

Thanks for the awesome blog post. I read it extensively when I was trying to use promises for everything. I ended up deciding that it was not worth the trouble of learning a lib with like 30 methods for a tiny bit of syntax sugar. Callbacks have never even really bothered me. Named functions FTW.

Re: How I want to write Node: Stream all the things

#76

Post by tjholowaychuk »

kimjotki2 wrote: post #72

It looks like this whole notion of 'stream' is just a syntactic sugar for javascript guys who lost themselves in a bunch of nested stupid callbacks, which is worse than lisp parens. Instead of nesting whole callbacks, create a stream in the middle; execute first half of callback chain and dump the result into the stream so that next half of callback chain can be executed later. Why is this so an enlightenment for nod…

yup! node does streams horribly wrong

Re: How I want to write Node: Stream all the things

#77

Post by rubiquity »

hamburglar wrote: post #10

This is highly intriguing, but I must ask why the JS community has this fascination with obscure identifiers like "_". It decreases readability when what should be a logically-chosen descriptive identifier for your class is replaced with a single character that visually recedes into the language syntax. Edit: I've grudgingly given jquery a pass on this because of its ubiquity, but come on, a stream library? Not to me…

Underscore uses the "_" variable because, well the library is actually named "underscore." Highland uses the "_" because... I don't have anything nice to say.

Re: How I want to write Node: Stream all the things

#79

Post by codygman »

lukasm wrote: post #78

I really like Node, but I want a language with sane semantics. What's the best option apart from JS and CoffeScript. TypeScript is awesome, but I'm afraid that there will no good community, because of MS stigma.

You can use Haskell for the same semantics if I understand you correctly. Actually coming from Node, Go might be a better fit.

Re: How I want to write Node: Stream all the things

#80

Post by rubiquity »

onestone wrote: post #18
glenjamin wrote: post #6

If you're doing Node.js, Caolan's async library is pretty much part of the standard toolkit. I know Caolan's been thinking about this and reworking it for a while, so I'll be interested to see whether it manages to see significant takeup.

Indeed caolan/async has been a de-facto standard until recently. But for me personally it has become obsolete, with the standardization of generators and promises.

This. The best part of Harmony is to wipe libraries like this off the face of the planet. I dread the days of trying to pick between 10 different flow control libraries. A few years ago 5 new flow control libraries were coming out every month.
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