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@mitsuhiko Not gonna happen ;) Forbidding shadowing altogether is a huge win, and a huge conceptual simplification. How arrogant! You'd think he'd step back fo

@mitsuhiko Not gonna happen ;) Forbidding shadowing altogether is a huge win, and a huge conceptual simplification. How arrogant! You'd think he'd step back for a second and consider the suggestion, but it sounds like he's on autopilot.

latchkey 15y ago
It sounds like he had 140 characters to succinctly say what he wanted to say.
statictype 15y ago
Everyday there seems to be a new post on HN, complete with inflammatory headline, criticizing Coffeescript in someway because it doesn't work in the exact way the author expected. There are lots of people throwing in their $0.02 on how the language should work without having joined the mailing list or seen any discussions on the thought process behind its features. I'm not saying the suggestion made isn't reasonable, but I can understand glib replies like this from the author that don't make too much effort to explain his stance more than 140 characters.
- showell30 15y ago
  In fairness, Armin (the author the blog post) did engage Jeremy (the author of coffeescript) on this issue over twitter. I wish that he would allow comments on his blog. I also wish that he could engage the broader CS community in a proper forum before dissing the language and/or creating a fork of the language. He's overreacting. This whole blog post apparently started because he had a naming collision with "log" in one of his programs. CS does have a mailing list, but most of the action happens via github issues.
  - the_mitsuhiko 15y ago
    > I wish that he would allow comments on his blog. Why? Hackernews and reddit exist and everybody is free to send me a mail or contact me on twitter. This way I do not have to moderate any comments or deal with spam. > I also wish that he could engage the broader CS community in a proper forum before dissing the language and/or creating a fork of the language. And do what? Duplicating an issue that is already there? Commenting on a dead issue? The author has expressed his unwillingness to deal with this issue so why should I reopen the issue there? > He's overreacting. How am I? I wrote a very short blog post about why I think the scoping is bad and how it caused me problems. Many people asked me on Twitter why I think the scoping does not work as good as it should and since I only have 140 characters to explain stuff there I wrote it to my blog. How else should I communicate that? > CS does have a mailing list, but most of the action happens via github issues. There is an issue about this topic from a year ago which was closed and the author does not want this to be changed. I am okay with that, a language needs leadership. That does not mean however that other people should not know about this issue when they design the next programming language.
    - showell30 15y ago
      I wish that you would allow comments on your blog, so that folks following your twitter link would be able to see both sides of the issue, but I obviously understand your spam issues, which is why I said "wish" and not "should". I wish that you would engage the CS community on this topic without the sole agenda of getting this fixed. It's true that the issue was put to rest a while ago, but the decision wasn't made in a vacuum--there was consensus involved. I think it's a little unfair to say that Jeremy "has expressed his unwillingness to deal with this issue"; that makes it sound like he was dismissing you or dismissing further debate on this, when in fact he just told you what had already been decided. When I say you're overreacting on this issue, it's just my opinion, so don't get too worked up about it. You had a bug. "Log" means two things. IMHO you don't need to fork coffeescript; that would be a gross overreaction, but YMMV. You are not doing anything wrong by taking the time to write up your opinion in a blog--if I implied that in any way, it was not out of malice; it was just imprecise writing on my part.
    - dtf 15y ago
      For what it's worth, thanks for that detailed article. I've just used Coffeescript for a large-ish WebGL project and had no idea of that behaviour. I got freaked out when I got to the bottom of that first fragment and saw log vs log. I'm going to keep using Coffeescript, I love it. Maybe this kind of scoping isn't the best decision for modularity and teamwork, but on reflection at least the rules are simple and consistent enough for a single programmer to keep in mind.
    - rimantas 15y ago
      > How else should I communicate that? Who says you should?
    - jashkenas 15y ago
      Blog posts about (and against) CoffeeScript features are great, as is discussion on HN, as is discussion on the issues pages. In addition, nothing in CoffeeScript is set in stone -- because every script compiled with every version of CoffeeScript is compatible with every other version, we're much more comfortable making changes to the language than we otherwise would be. If you can make the case that this change is a good idea, we'll definitely make it. So feel free to comment on the old issue or open a new one if you wish.
  - colin_jack 15y ago
    > He's overreacting. This whole blog post apparently started because he had a naming collision with "log" in one of his programs Surprised at that reaction, he's had a problem and he's written an excellent blog post about it.
locci 15y ago
I think this is a recurring discussion from the dawn of coffeescript. See for example: https://github.com/jashkenas/coffee-script/issues/238 https://github.com/jashkenas/coffee-script/issues/238 I really don't understand why this isn't being fixed: doesn't global by default break encapsulation? I'm probably missing something, but this is the main reason I haven't tried coffeescript yet.
- showell30 15y ago
  Just to be completely clear, variables are only at top level scope if you declare them at top-level scope. The variables "x" below are completely encapsulated within f1 and f2. The variables at top-level scope are intentional in the code below--I really do intend f1, f2, and how_many_times_functions_have_been_called to refer to the same entity throughout the file. how_many_times_functions_have_been_called = 0 f1 = -> how_many_times_functions_have_been_called += 1 # refers to top-level scope console.log x # undefined x = 1 console.log x # 1 f2 = -> f1() # refers to f1 at top-level scope how_many_times_functions_have_been_called += 1 # refers to lop-level scope console.log x # undefined x = 2 console.log x # 2 f1() # you can call f1, it's at top-level scope f2() # you can call f2, it's at top-level scope console.log how_many_times_functions_have_been_called # 3, refers to top-level scope console.log x? # false, x does not exist at top_level scope
  - locci 15y ago
    Yes, I probably wasn't very clear: what I meant is that a programmer writing a function somewhere in a program must have a complete knowledge of the scope where the function is and will be in the future, including changes in global variables exposed by the interpreter/browser. In the end I would find me forced to add a prefix to all the variables in order to avoid collisions, just like I would be forced to do, if the language only had a single global scope. This behaviour seems quite unreasonable to me, but I haven't been able to find explanations about it, other than it's expected behaviour.
    - jashkenas 15y ago
danso 15y ago
I think Jeremy probably has one of the highest programming-chops-to-arrogance ratios among today's top programmers. It was a tweet, he said what he needed to say. He's been more than willing on HN to step in and explain Coffeescript to critics and offer helpful critiques of competing frameworks (well, in the context of Backbone). Here's how he introduced CoffeeScript to HN almost exactly two years from today: http://news.ycombinator.com/item?id=1014080 http://news.ycombinator.com/item?id=1014080
- tjholowaychuk 15y ago
  "top programmers" don't write javascript and web apps, we're all pretty much noobs
  - murloc 15y ago
    But he writes coffeescript so unlike you he's a "top programmer". except for times when he writes javascript which probably would be when hes drunk or for whatever reasons his IQ has dropped.
    - tjholowaychuk 15y ago
      99% of the popular people out there are just above average enough to make useful projects for those lesser experienced. Most truly talented people are not very well known, they're busy hacking on v8, the kernel etc. Tools for average programming just get more of a spotlight. Is Express complex? no, people just use it, is coffeescript complex? no, is boostrap complex? no..
      - danso 15y ago
        That sounds like a really accurate statistic. So what's your metric for this? Besides the obvious law that low-level code is the only grounds for elite coding, I mean.
        murloc 15y ago
equark 15y ago
Don't jump the gun. The reason is that he's already had many discussions about this and has formed an opinion. See: https://github.com/jashkenas/coffee-script/issues/712 https://github.com/jashkenas/coffee-script/issues/712 https://github.com/jashkenas/coffee-script/issues/238 https://github.com/jashkenas/coffee-script/issues/238 Whether he's right is another question. But if you don't like his decision you can use the Coco (https://github.com/satyr/coco https://github.com/satyr/coco) fork which fixes it by introducing := for nonlocal assignment.
- barrkel 15y ago
  The reasoning basically seems to be "if you misuse this feature (i.e. have top-level symbols), you'll get bugs (like the OP discovered), therefore don't misuse this feature (i.e. keep your top scopes clean), and therefore you won't get bugs, and therefore it's not a problem with CoffeeScript". It shouldn't take a lot of thought to see why this is a somewhat user-hostile, passive-aggressive approach for a language. If something is ill-advised, the language should actively steer you away from it, not dissuade you with subtle bugs a few thousand lines of code down the road. I think this scheme would be more workable if sigils or similar conventions of some kind were mandatory for top-level symbols. Then it would be much harder to accidentally wander into this problem. The language he seems to be drawing inspiration from, Ruby, does do this.
  - jashkenas 15y ago
    I'm afraid that's not quite the reasoning... Like everything in languages (or APIs), there's a tradeoff here. By making scoping automatic, and (hopefully) forbidding shadowing, you can make the language conceptually simpler. Think of it as making variables be "referentially transparent" in terms of their lexical scope. Everywhere you see "A" within a given lexical scope -- you know that "A" always refers to the same thing. In a language with "var" and with shadowing, "A" could mean many different things within any given lexical scope, and you have to hunt for the nearest declaration to tell which one it is. On the downside, you have what Armin describes: If you happen to try to use the same name for two different things within the same lexical scope, it won't work. Since it's always the case that you are able to choose a more descriptive name for your variable, and gain clearer code by it, I think it's very much a tradeoff worth making.
whateverer 15y ago
@mitsuhiko Not gonna happen ;) Forbidding shadowing altogether is a huge win, and a huge conceptual simplification. Poppycock. It doesn't get simpler than a. newly bound variables are new b. any variable which wasn't bound in the present scope must be bound in a enclosing scope. If your language makes it much more complicated than First Order Logic (http://cnx.org/content/m12081/latest/ http://cnx.org/content/m12081/latest/), you're doing it wrong. Of course, it's kind of socially acceptable to get wrong because a lot of language designers didn't think it through and used the same operator for both binding and reassigning a variable (i.e. '=').
jashkenas 15y ago
Sorry -- that was supposed to be a friendly tweet-sized response. The discussion about this "feature" is always good to have, especially because it's one of the most rightfully controversial changes that CoffeeScript makes to JavaScript semantics. There are dozens of lengthy conversations about this in the CoffeeScript issues, if you'd like to take a deeper look.

latchkey 15y ago

It sounds like he had 140 characters to succinctly say what he wanted to say.

statictype 15y ago

Everyday there seems to be a new post on HN, complete with inflammatory headline, criticizing Coffeescript in someway because it doesn't work in the exact way the author expected. There are lots of people throwing in their $0.02 on how the language should work without having joined the mailing list or seen any discussions on the thought process behind its features. I'm not saying the suggestion made isn't reasonable, but I can understand glib replies like this from the author that don't make too much effort to explain his stance more than 140 characters.

showell30 15y ago
In fairness, Armin (the author the blog post) did engage Jeremy (the author of coffeescript) on this issue over twitter. I wish that he would allow comments on his blog. I also wish that he could engage the broader CS community in a proper forum before dissing the language and/or creating a fork of the language. He's overreacting. This whole blog post apparently started because he had a naming collision with "log" in one of his programs. CS does have a mailing list, but most of the action happens via github issues.
- the_mitsuhiko 15y ago
  > I wish that he would allow comments on his blog. Why? Hackernews and reddit exist and everybody is free to send me a mail or contact me on twitter. This way I do not have to moderate any comments or deal with spam. > I also wish that he could engage the broader CS community in a proper forum before dissing the language and/or creating a fork of the language. And do what? Duplicating an issue that is already there? Commenting on a dead issue? The author has expressed his unwillingness to deal with this issue so why should I reopen the issue there? > He's overreacting. How am I? I wrote a very short blog post about why I think the scoping is bad and how it caused me problems. Many people asked me on Twitter why I think the scoping does not work as good as it should and since I only have 140 characters to explain stuff there I wrote it to my blog. How else should I communicate that? > CS does have a mailing list, but most of the action happens via github issues. There is an issue about this topic from a year ago which was closed and the author does not want this to be changed. I am okay with that, a language needs leadership. That does not mean however that other people should not know about this issue when they design the next programming language.
  - showell30 15y ago
    I wish that you would allow comments on your blog, so that folks following your twitter link would be able to see both sides of the issue, but I obviously understand your spam issues, which is why I said "wish" and not "should". I wish that you would engage the CS community on this topic without the sole agenda of getting this fixed. It's true that the issue was put to rest a while ago, but the decision wasn't made in a vacuum--there was consensus involved. I think it's a little unfair to say that Jeremy "has expressed his unwillingness to deal with this issue"; that makes it sound like he was dismissing you or dismissing further debate on this, when in fact he just told you what had already been decided. When I say you're overreacting on this issue, it's just my opinion, so don't get too worked up about it. You had a bug. "Log" means two things. IMHO you don't need to fork coffeescript; that would be a gross overreaction, but YMMV. You are not doing anything wrong by taking the time to write up your opinion in a blog--if I implied that in any way, it was not out of malice; it was just imprecise writing on my part.
  - dtf 15y ago
    For what it's worth, thanks for that detailed article. I've just used Coffeescript for a large-ish WebGL project and had no idea of that behaviour. I got freaked out when I got to the bottom of that first fragment and saw log vs log. I'm going to keep using Coffeescript, I love it. Maybe this kind of scoping isn't the best decision for modularity and teamwork, but on reflection at least the rules are simple and consistent enough for a single programmer to keep in mind.
  - rimantas 15y ago
    > How else should I communicate that? Who says you should?
  - jashkenas 15y ago
    Blog posts about (and against) CoffeeScript features are great, as is discussion on HN, as is discussion on the issues pages. In addition, nothing in CoffeeScript is set in stone -- because every script compiled with every version of CoffeeScript is compatible with every other version, we're much more comfortable making changes to the language than we otherwise would be. If you can make the case that this change is a good idea, we'll definitely make it. So feel free to comment on the old issue or open a new one if you wish.
- colin_jack 15y ago
  > He's overreacting. This whole blog post apparently started because he had a naming collision with "log" in one of his programs Surprised at that reaction, he's had a problem and he's written an excellent blog post about it.

locci 15y ago

I think this is a recurring discussion from the dawn of coffeescript. See for example: https://github.com/jashkenas/coffee-script/issues/238 https://github.com/jashkenas/coffee-script/issues/238 I really don't understand why this isn't being fixed: doesn't global by default break encapsulation? I'm probably missing something, but this is the main reason I haven't tried coffeescript yet.

showell30 15y ago
Just to be completely clear, variables are only at top level scope if you declare them at top-level scope. The variables "x" below are completely encapsulated within f1 and f2. The variables at top-level scope are intentional in the code below--I really do intend f1, f2, and how_many_times_functions_have_been_called to refer to the same entity throughout the file. how_many_times_functions_have_been_called = 0 f1 = -> how_many_times_functions_have_been_called += 1 # refers to top-level scope console.log x # undefined x = 1 console.log x # 1 f2 = -> f1() # refers to f1 at top-level scope how_many_times_functions_have_been_called += 1 # refers to lop-level scope console.log x # undefined x = 2 console.log x # 2 f1() # you can call f1, it's at top-level scope f2() # you can call f2, it's at top-level scope console.log how_many_times_functions_have_been_called # 3, refers to top-level scope console.log x? # false, x does not exist at top_level scope
- locci 15y ago
  Yes, I probably wasn't very clear: what I meant is that a programmer writing a function somewhere in a program must have a complete knowledge of the scope where the function is and will be in the future, including changes in global variables exposed by the interpreter/browser. In the end I would find me forced to add a prefix to all the variables in order to avoid collisions, just like I would be forced to do, if the language only had a single global scope. This behaviour seems quite unreasonable to me, but I haven't been able to find explanations about it, other than it's expected behaviour.
  - jashkenas 15y ago

danso 15y ago

I think Jeremy probably has one of the highest programming-chops-to-arrogance ratios among today's top programmers. It was a tweet, he said what he needed to say. He's been more than willing on HN to step in and explain Coffeescript to critics and offer helpful critiques of competing frameworks (well, in the context of Backbone). Here's how he introduced CoffeeScript to HN almost exactly two years from today: http://news.ycombinator.com/item?id=1014080 http://news.ycombinator.com/item?id=1014080

tjholowaychuk 15y ago
"top programmers" don't write javascript and web apps, we're all pretty much noobs
- murloc 15y ago
  But he writes coffeescript so unlike you he's a "top programmer". except for times when he writes javascript which probably would be when hes drunk or for whatever reasons his IQ has dropped.
  - tjholowaychuk 15y ago
    99% of the popular people out there are just above average enough to make useful projects for those lesser experienced. Most truly talented people are not very well known, they're busy hacking on v8, the kernel etc. Tools for average programming just get more of a spotlight. Is Express complex? no, people just use it, is coffeescript complex? no, is boostrap complex? no..
    - danso 15y ago
      That sounds like a really accurate statistic. So what's your metric for this? Besides the obvious law that low-level code is the only grounds for elite coding, I mean.
      - murloc 15y ago

equark 15y ago

Don't jump the gun. The reason is that he's already had many discussions about this and has formed an opinion. See: https://github.com/jashkenas/coffee-script/issues/712 https://github.com/jashkenas/coffee-script/issues/712 https://github.com/jashkenas/coffee-script/issues/238 https://github.com/jashkenas/coffee-script/issues/238 Whether he's right is another question. But if you don't like his decision you can use the Coco (https://github.com/satyr/coco https://github.com/satyr/coco) fork which fixes it by introducing := for nonlocal assignment.

barrkel 15y ago
The reasoning basically seems to be "if you misuse this feature (i.e. have top-level symbols), you'll get bugs (like the OP discovered), therefore don't misuse this feature (i.e. keep your top scopes clean), and therefore you won't get bugs, and therefore it's not a problem with CoffeeScript". It shouldn't take a lot of thought to see why this is a somewhat user-hostile, passive-aggressive approach for a language. If something is ill-advised, the language should actively steer you away from it, not dissuade you with subtle bugs a few thousand lines of code down the road. I think this scheme would be more workable if sigils or similar conventions of some kind were mandatory for top-level symbols. Then it would be much harder to accidentally wander into this problem. The language he seems to be drawing inspiration from, Ruby, does do this.
- jashkenas 15y ago
  I'm afraid that's not quite the reasoning... Like everything in languages (or APIs), there's a tradeoff here. By making scoping automatic, and (hopefully) forbidding shadowing, you can make the language conceptually simpler. Think of it as making variables be "referentially transparent" in terms of their lexical scope. Everywhere you see "A" within a given lexical scope -- you know that "A" always refers to the same thing. In a language with "var" and with shadowing, "A" could mean many different things within any given lexical scope, and you have to hunt for the nearest declaration to tell which one it is. On the downside, you have what Armin describes: If you happen to try to use the same name for two different things within the same lexical scope, it won't work. Since it's always the case that you are able to choose a more descriptive name for your variable, and gain clearer code by it, I think it's very much a tradeoff worth making.

whateverer 15y ago

@mitsuhiko Not gonna happen ;) Forbidding shadowing altogether is a huge win, and a huge conceptual simplification. Poppycock. It doesn't get simpler than a. newly bound variables are new b. any variable which wasn't bound in the present scope must be bound in a enclosing scope. If your language makes it much more complicated than First Order Logic (http://cnx.org/content/m12081/latest/ http://cnx.org/content/m12081/latest/), you're doing it wrong. Of course, it's kind of socially acceptable to get wrong because a lot of language designers didn't think it through and used the same operator for both binding and reassigning a variable (i.e. '=').

jashkenas 15y ago

Sorry -- that was supposed to be a friendly tweet-sized response. The discussion about this "feature" is always good to have, especially because it's one of the most rightfully controversial changes that CoffeeScript makes to JavaScript semantics. There are dozens of lengthy conversations about this in the CoffeeScript issues, if you'd like to take a deeper look.