11 ms·

Opal - Ruby to Javascript compiler

130 points by cap10morgan 14y ago

jonny_eh 14y ago
While very impressive it makes me nervous. The JS it outputs just in the basic tutorial looks extremely complex, I'd hate to debug that code! Compare with CoffeeScript, where the output is quite easy to follow, and therefore debug.
- wtetzner 14y ago
  The difference is that CoffeeScript was designed to compile to JavaScript, so it can adopt JavaScript semantics. Ruby doesn't have the same semantics as JavaScript, so you can't have a 1-to-1 mapping of language constructs.
  - jonny_eh 14y ago
    Oh I get that. I'm sure they did as good as job as possible, but it still makes me nervous. As nice a language as Ruby is, I don't think it's worth the trade-off. I'll stick with CoffeeScript since it's a nice compromise between Ruby and JavaScript.
- denysonique 14y ago
  OpalScript is going to solve this problem
1qaz2wsx3edc 14y ago
Yup, that's some good brainfuck: (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice, __klass = __opal.klass; var adam = nil, __a, __b; (__b = [1, 2, 3, 4], __b.$each._p = (__a = function(a) { if (a == null) a = nil; return this.$puts(a) }, __a._s = self, __a), __b.$each()); (function(__base, __super){ // line 5, (file), class Foo function Foo() {}; Foo = __klass(__base, __super, "Foo", Foo); var Foo_prototype = Foo.prototype, __scope = Foo._scope; return Foo_prototype.$name = function() { if (this.name == null) this.name = nil; return this.name }, Foo_prototype['$name='] = function(val) { return this.name = val }, nil })(self, null); adam = __scope.Foo.$new(); adam['$name=']("Adam Beynon"); return self.$puts(adam.$name()); })();
- ghayes 14y ago
  If you look at this rationally, it's actually pretty sane. It's just very simple JavaScript OOP inline with translated code. Even more beautiful is the output of modules: module Run def run puts "I am running!" end end module Jump def jump puts "I am jumping!" end end class Foo include Run include Jump end mario = Foo.new mario.run mario.jump translates to: (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice, __module = __opal.module, __klass = __opal.klass; // Define Mario var mario = nil; // Javascript "Run" class (function(__base){ // line 2, (file), module Run function Run() {}; Run = __module(__base, "Run", Run); var Run_prototype = Run.prototype, __scope = Run._scope; Run_prototype.$run = function() { return this.$puts("I am running!"); } ;Run._donate(["$run"]); })(self); // Javascript "Jump" class (function(__base){ // line 8, (file), module Jump function Jump() {}; Jump = __module(__base, "Jump", Jump); var Jump_prototype = Jump.prototype, __scope = Jump._scope; Jump_prototype.$jump = function() { return this.$puts("I am jumping!"); } ;Jump._donate(["$jump"]); })(self); // JavaScript "Foo" class (function(__base, __super){ // line 14, (file), class Foo function Foo() {}; Foo = __klass(__base, __super, "Foo", Foo); var Foo_prototype = Foo.prototype, __scope = Foo._scope; // $include Run / Jump Foo.$include(__scope.Run); return Foo.$include(__scope.Jump); })(self, null); // The ruby executing code translation mario = __scope.Foo.$new(); mario.$run(); return mario.$jump(); })();
  - sic1 14y ago
    While we are posting contrived examples. What was ever wrong with this? var Foo = function() {}; Foo.prototype.jump = function() { return "I jump." }; Foo.prototype.run = function() { return "I run." }; var mario = new Foo(); mario.run(); mario.jump(); I can't imagine that opal code running nearly as fast as javascript. And if we are waving around compiled js - coffeescript does a much better job of being readable. You just black-boxed the whole thing. I like to know what is happening with my js. Cool for the rubyist in you i guess. I just kinda go o_0
5vforest 14y ago
What the use case for something like this? Am I missing something?
- astrodust 14y ago
  Porting existing code without having to re-implement. Keeping a single reference implementation of a particular method.
  - rgovind 14y ago
    on related note, when and if node.js takes off, does it make sense to have a php-to-javascript compiler so people don't need to redo a lot of stuff?
- mikesea 14y ago
  Rewriting your entire Rails app in Node so that it goes faster!
- Sanddancer 14y ago
  Using the language you're comfortable with client-side. Though what this really shows, once again, is that we really need a good, open, virtual machine specification for client-side byte code so we aren't stuck with the same javascript hammer for all problems.
  - MatthewPhillips 14y ago
    ? Doesn't this show that we aren't stuck with the same hammer? Opal is a different hammer.
    - rrouse 14y ago
      Not really. You're still using Javascript in the end.
      - ville 14y ago
DanielRibeiro 14y ago
Cool idea. Not the first attempt though: http://hotruby.yukoba.jp/ http://hotruby.yukoba.jp/ https://github.com/whitequark/coldruby https://github.com/whitequark/coldruby http://rb2js.rubyforge.org/ http://rb2js.rubyforge.org/ http://www.ntecs.de/blog/articles/2007/01/08/rubyjs-javascript-no-thank-you/ http://www.ntecs.de/blog/articles/2007/01/08/rubyjs-javascri... https://github.com/jessesielaff/red https://github.com/jessesielaff/red http://www.playmycode.com/docs/quby http://www.playmycode.com/docs/quby https://github.com/mattknox/8ball https://github.com/mattknox/8ball Unfortunately, none of them seem to be to handle the mor dynamic features of ruby, like method_missing, which diminishes the possibility of reusing existing ruby code in the browser.
- pygy_ 14y ago
  Javascript Harmony (ES6) Proxies will allow to define getter catchall and other kinds of traps. See https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Proxy https://developer.mozilla.org/en-US/docs/JavaScript/Referenc...
  - tlack 14y ago
    Minor FYI: for this who want to play with Proxies right now, you can use a recent-ish copy of node invoked with node --harmony_proxies Enjoy!
    - pygy_ 14y ago
      Actually, V8 implements an older version of the spec. You can get a polyfill created by the designer of the Proxy spec here: https://github.com/tvcutsem/harmony-reflect https://github.com/tvcutsem/harmony-reflect It requires `node --harmony` (actually only Harmony Proxies and Harmony WeakMaps, but the rest doesn't hurt.)
- tlrobinson 14y ago
  While I never finished it, my "CappRuby" prototype supported method_missing since it compiled to use the Objective-J runtime. https://github.com/tlrobinson/cappruby https://github.com/tlrobinson/cappruby
Xcelerate 14y ago
I really like this idea of compiling code to Javascript. Brenden Eich makes some good points for it in his series of slides (starting here: http://brendaneich.github.com/Strange-Loop-2012/#/21 http://brendaneich.github.com/Strange-Loop-2012/#/21). I'm working on a little programming language myself that compiles to Javascript. In most languages that do this, I wish there was better information on the mapping between the domain language and its Javascript codomain. I think this would be a good open source project idea: a tool to assist in the compilation of various languages to Javascript. Something to the effect of how source lines in C can be printed above their generated assembly. Anyone want to give it a shot?
- spacemanaki 14y ago
  I think what you've described would be mostly accomplished by source maps: http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/ http://www.html5rocks.com/en/tutorials/developertools/source...
- slurgfest 14y ago
  Why is it not possible to engineer a basic VM to do this job from the start, rather than retrofitting Javascript to act as a bytecode?
  - adrusi 14y ago
    implementing a vm in javascript would be noticeably slower than compiling directly to javascript. Dart has its own vm, which will eventually be bundled with chrome since it's a google-backed project, but for backwards compatibility it still needs a dart source to javascript source compiler.
dyscrete 14y ago
It's a great idea, but it seems ridiculous how even simple arithmetic gets translated to an unreadable mess of javascript. puts 4 + 2 + 5 + (19 + 3 * 4) - 8 / 10 translates to: (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice; var __a, __b, __c, __d, __e, __f, __g, __h; return self.$puts((__a = (__c = (__e = (__g = 4, __h = 2, typeof(__g) === 'number' ? __g + __h : __g['$+'](__h)), __f = 5, typeof(__e) === 'number' ? __e + __f : __e['$+'](__f)), __d = (__e = 19, __f = (__g = 3, __h = 4, typeof(__g) === 'number' ? __g * __h : __g['$*'](__h)), typeof(__e) === 'number' ? __e + __f : __e['$+'](__f)), typeof(__c) === 'number' ? __c + __d : __c['$+'](__d)), __b = (__c = 8, __d = 10, typeof(__c) === 'number' ? __c / __d : __c['$/'](__d)), typeof(__a) === 'number' ? __a - __b : __a['$-'](__b))) })();
- Scriptor 14y ago
  It's really not terribly complicated to figure out what it does, here's the formatted version for adding two numbers (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice; var __a, __b; return self.$puts((__a = 1, __b = 2, typeof(__a) === 'number' ? __a + __b : __a['$+'](__b))) })(); The first line just declares some Opal-specific variables (__scope, nil, __breaker, etc.), which I guess are created whether or not they're actually used. The second line defines the temporary variables used to store the numbers. Then, depending on the type, it either actually adds them or use its own '$+' function, which I guess it adds to the prototype for all objects. In terms of having to ever debug something like that, I agree that it'd probably be a huge pain.
  - scott_s 14y ago
    I agree that it's reasonable. Consider this C program: int main() { return 4 + 2 + 5 + (19 + 3 * 4) - 8 / 10; } Becomes the following assembly: .section __TEXT,__text,regular,pure_instructions .globl _main .align 4, 0x90 _main: Leh_func_begin1: pushq %rbp Ltmp0: movq %rsp, %rbp Ltmp1: movl $42, -8(%rbp) movl -8(%rbp), %eax movl %eax, -4(%rbp) movl -4(%rbp), %eax popq %rbp ret Leh_func_end1: Yes, that's going from "high level" to "low level," but much of the same concepts exist. You have to set up a bunch of stuff unrelated to the computation first, which in the Ruby-to-JavaScript case means setting up the runtime system. In the C-to-assembly case, it means mucking around with the stack. Then the actual computation may not be the most optimal thing, because it was generated by a general framework which can handle any arbitrary computation. Reducing it to something more reasonable looking is an optimization.
jblock 14y ago
Source maps? Source maps.
lexy0202 14y ago
Can you interact with the dom inside opal?
- marcamillion 14y ago
  Seems so: > Document['.post .title'].html = @post[:title] Document['.post .body'].html = @post[:body] Document['.post .comments'].html = comments_html From https://github.com/opal/opal-rails#readme https://github.com/opal/opal-rails#readme
sambuna 14y ago
I certainly see future for this!
doktrin 14y ago
Being relatively new to cross-language compilation, how are one language's class APIs typically translated into another? For example : [1,2,3].shuffle [turns into] => (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice; return [1, 2, 3].$shuffle() })(); Of course, since JS arrays do not have a "shuffle" method, the output reads : TypeError: Object 1,2,3 has no method '$shuffle' Is the answer to simply use class/object methods that are present in both languages?
- mossity 14y ago
  Could probably also include something like Sugar.js or Underscore.js that tries to bring a lot of the missing syntactic sugar to JS.
vjeux 14y ago
Unfortunately their hash table uses Javascript objects. Therefore it does not behave exactly like Ruby. Eg: # Opal h = Hash.new h['0'] = 1 h[0] = 2 print h # {"0"=>2} # Ruby h = Hash.new h['0'] = 1 h[0] = 2 print h # {"0"=>1, 0=>2} It is very hard to reproduce those low level specifications without rebuilding everything from scratch sadly :(
- lucian1900 14y ago
  ECMA5 has real maps, which Opal could use. Some browsers support them already.
goggles99 14y ago
Can't those standards committees just do something right for once and create a standard for a vm that will run in the browser (a la Dartium)? Stop this monopoly and oppression of innovation!!!
jhrobert 14y ago
They lost me at the "nil" section. RubyScript is what we need => efficient code, à la coffeescript, with a Ruby syntax. There is some impedance mismatch between ruby & javascript semantics. Trying to hide this fact has a cost in terms of performance. I would love to have some ruby syntax as long as it does not compromize the speed of my code. There is a trend these days where syntax and semantics are becoming orthogonal, that's nice. Hence GoScript, PascalScript, PrologScript, CppScript, SmallScript... Thanks to sourcemaps the issue of the generated code readability has disappeared. Only the performance matters from now on.
- SilasX 14y ago
  >RubyScript is what we need => efficient code, à la coffeescript, with a Ruby syntax. Why not make a Ruby -> Coffeescript compiler, since they're a lot closer in the first place?

130 points by cap10morgan 14y ago

While very impressive it makes me nervous. The JS it outputs just in the basic tutorial looks extremely complex, I'd hate to debug that code! Compare with CoffeeScript, where the output is quite easy to follow, and therefore debug.

wtetzner 14y ago
The difference is that CoffeeScript was designed to compile to JavaScript, so it can adopt JavaScript semantics. Ruby doesn't have the same semantics as JavaScript, so you can't have a 1-to-1 mapping of language constructs.
- jonny_eh 14y ago
  Oh I get that. I'm sure they did as good as job as possible, but it still makes me nervous. As nice a language as Ruby is, I don't think it's worth the trade-off. I'll stick with CoffeeScript since it's a nice compromise between Ruby and JavaScript.
denysonique 14y ago
OpalScript is going to solve this problem

1qaz2wsx3edc 14y ago

Yup, that's some good brainfuck: (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice, __klass = __opal.klass; var adam = nil, __a, __b; (__b = [1, 2, 3, 4], __b.$each._p = (__a = function(a) { if (a == null) a = nil; return this.$puts(a) }, __a._s = self, __a), __b.$each()); (function(__base, __super){ // line 5, (file), class Foo function Foo() {}; Foo = __klass(__base, __super, "Foo", Foo); var Foo_prototype = Foo.prototype, __scope = Foo._scope; return Foo_prototype.$name = function() { if (this.name == null) this.name = nil; return this.name }, Foo_prototype['$name='] = function(val) { return this.name = val }, nil })(self, null); adam = __scope.Foo.$new(); adam['$name=']("Adam Beynon"); return self.$puts(adam.$name()); })();

ghayes 14y ago
If you look at this rationally, it's actually pretty sane. It's just very simple JavaScript OOP inline with translated code. Even more beautiful is the output of modules: module Run def run puts "I am running!" end end module Jump def jump puts "I am jumping!" end end class Foo include Run include Jump end mario = Foo.new mario.run mario.jump translates to: (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice, __module = __opal.module, __klass = __opal.klass; // Define Mario var mario = nil; // Javascript "Run" class (function(__base){ // line 2, (file), module Run function Run() {}; Run = __module(__base, "Run", Run); var Run_prototype = Run.prototype, __scope = Run._scope; Run_prototype.$run = function() { return this.$puts("I am running!"); } ;Run._donate(["$run"]); })(self); // Javascript "Jump" class (function(__base){ // line 8, (file), module Jump function Jump() {}; Jump = __module(__base, "Jump", Jump); var Jump_prototype = Jump.prototype, __scope = Jump._scope; Jump_prototype.$jump = function() { return this.$puts("I am jumping!"); } ;Jump._donate(["$jump"]); })(self); // JavaScript "Foo" class (function(__base, __super){ // line 14, (file), class Foo function Foo() {}; Foo = __klass(__base, __super, "Foo", Foo); var Foo_prototype = Foo.prototype, __scope = Foo._scope; // $include Run / Jump Foo.$include(__scope.Run); return Foo.$include(__scope.Jump); })(self, null); // The ruby executing code translation mario = __scope.Foo.$new(); mario.$run(); return mario.$jump(); })();
- sic1 14y ago
  While we are posting contrived examples. What was ever wrong with this? var Foo = function() {}; Foo.prototype.jump = function() { return "I jump." }; Foo.prototype.run = function() { return "I run." }; var mario = new Foo(); mario.run(); mario.jump(); I can't imagine that opal code running nearly as fast as javascript. And if we are waving around compiled js - coffeescript does a much better job of being readable. You just black-boxed the whole thing. I like to know what is happening with my js. Cool for the rubyist in you i guess. I just kinda go o_0

5vforest 14y ago

What the use case for something like this? Am I missing something?

astrodust 14y ago
Porting existing code without having to re-implement. Keeping a single reference implementation of a particular method.
- rgovind 14y ago
  on related note, when and if node.js takes off, does it make sense to have a php-to-javascript compiler so people don't need to redo a lot of stuff?
mikesea 14y ago
Rewriting your entire Rails app in Node so that it goes faster!
Sanddancer 14y ago
Using the language you're comfortable with client-side. Though what this really shows, once again, is that we really need a good, open, virtual machine specification for client-side byte code so we aren't stuck with the same javascript hammer for all problems.
- MatthewPhillips 14y ago
  ? Doesn't this show that we aren't stuck with the same hammer? Opal is a different hammer.
  - rrouse 14y ago
    Not really. You're still using Javascript in the end.
    - ville 14y ago

DanielRibeiro 14y ago

Cool idea. Not the first attempt though: http://hotruby.yukoba.jp/ http://hotruby.yukoba.jp/ https://github.com/whitequark/coldruby https://github.com/whitequark/coldruby http://rb2js.rubyforge.org/ http://rb2js.rubyforge.org/ http://www.ntecs.de/blog/articles/2007/01/08/rubyjs-javascript-no-thank-you/ http://www.ntecs.de/blog/articles/2007/01/08/rubyjs-javascri... https://github.com/jessesielaff/red https://github.com/jessesielaff/red http://www.playmycode.com/docs/quby http://www.playmycode.com/docs/quby https://github.com/mattknox/8ball https://github.com/mattknox/8ball Unfortunately, none of them seem to be to handle the mor dynamic features of ruby, like method_missing, which diminishes the possibility of reusing existing ruby code in the browser.

pygy_ 14y ago
Javascript Harmony (ES6) Proxies will allow to define getter catchall and other kinds of traps. See https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Proxy https://developer.mozilla.org/en-US/docs/JavaScript/Referenc...
- tlack 14y ago
  Minor FYI: for this who want to play with Proxies right now, you can use a recent-ish copy of node invoked with node --harmony_proxies Enjoy!
  - pygy_ 14y ago
    Actually, V8 implements an older version of the spec. You can get a polyfill created by the designer of the Proxy spec here: https://github.com/tvcutsem/harmony-reflect https://github.com/tvcutsem/harmony-reflect It requires `node --harmony` (actually only Harmony Proxies and Harmony WeakMaps, but the rest doesn't hurt.)
tlrobinson 14y ago
While I never finished it, my "CappRuby" prototype supported method_missing since it compiled to use the Objective-J runtime. https://github.com/tlrobinson/cappruby https://github.com/tlrobinson/cappruby

Xcelerate 14y ago

I really like this idea of compiling code to Javascript. Brenden Eich makes some good points for it in his series of slides (starting here: http://brendaneich.github.com/Strange-Loop-2012/#/21 http://brendaneich.github.com/Strange-Loop-2012/#/21). I'm working on a little programming language myself that compiles to Javascript. In most languages that do this, I wish there was better information on the mapping between the domain language and its Javascript codomain. I think this would be a good open source project idea: a tool to assist in the compilation of various languages to Javascript. Something to the effect of how source lines in C can be printed above their generated assembly. Anyone want to give it a shot?

spacemanaki 14y ago
I think what you've described would be mostly accomplished by source maps: http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/ http://www.html5rocks.com/en/tutorials/developertools/source...
slurgfest 14y ago
Why is it not possible to engineer a basic VM to do this job from the start, rather than retrofitting Javascript to act as a bytecode?
- adrusi 14y ago
  implementing a vm in javascript would be noticeably slower than compiling directly to javascript. Dart has its own vm, which will eventually be bundled with chrome since it's a google-backed project, but for backwards compatibility it still needs a dart source to javascript source compiler.

dyscrete 14y ago

It's a great idea, but it seems ridiculous how even simple arithmetic gets translated to an unreadable mess of javascript. puts 4 + 2 + 5 + (19 + 3 * 4) - 8 / 10 translates to: (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice; var __a, __b, __c, __d, __e, __f, __g, __h; return self.$puts((__a = (__c = (__e = (__g = 4, __h = 2, typeof(__g) === 'number' ? __g + __h : __g['$+'](__h)), __f = 5, typeof(__e) === 'number' ? __e + __f : __e['$+'](__f)), __d = (__e = 19, __f = (__g = 3, __h = 4, typeof(__g) === 'number' ? __g * __h : __g['$*'](__h)), typeof(__e) === 'number' ? __e + __f : __e['$+'](__f)), typeof(__c) === 'number' ? __c + __d : __c['$+'](__d)), __b = (__c = 8, __d = 10, typeof(__c) === 'number' ? __c / __d : __c['$/'](__d)), typeof(__a) === 'number' ? __a - __b : __a['$-'](__b))) })();

Scriptor 14y ago
It's really not terribly complicated to figure out what it does, here's the formatted version for adding two numbers (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice; var __a, __b; return self.$puts((__a = 1, __b = 2, typeof(__a) === 'number' ? __a + __b : __a['$+'](__b))) })(); The first line just declares some Opal-specific variables (__scope, nil, __breaker, etc.), which I guess are created whether or not they're actually used. The second line defines the temporary variables used to store the numbers. Then, depending on the type, it either actually adds them or use its own '$+' function, which I guess it adds to the prototype for all objects. In terms of having to ever debug something like that, I agree that it'd probably be a huge pain.
- scott_s 14y ago
  I agree that it's reasonable. Consider this C program: int main() { return 4 + 2 + 5 + (19 + 3 * 4) - 8 / 10; } Becomes the following assembly: .section __TEXT,__text,regular,pure_instructions .globl _main .align 4, 0x90 _main: Leh_func_begin1: pushq %rbp Ltmp0: movq %rsp, %rbp Ltmp1: movl $42, -8(%rbp) movl -8(%rbp), %eax movl %eax, -4(%rbp) movl -4(%rbp), %eax popq %rbp ret Leh_func_end1: Yes, that's going from "high level" to "low level," but much of the same concepts exist. You have to set up a bunch of stuff unrelated to the computation first, which in the Ruby-to-JavaScript case means setting up the runtime system. In the C-to-assembly case, it means mucking around with the stack. Then the actual computation may not be the most optimal thing, because it was generated by a general framework which can handle any arbitrary computation. Reducing it to something more reasonable looking is an optimization.

jblock 14y ago

Source maps? Source maps.

lexy0202 14y ago

Can you interact with the dom inside opal?

marcamillion 14y ago
Seems so: > Document['.post .title'].html = @post[:title] Document['.post .body'].html = @post[:body] Document['.post .comments'].html = comments_html From https://github.com/opal/opal-rails#readme https://github.com/opal/opal-rails#readme

sambuna 14y ago

I certainly see future for this!

doktrin 14y ago

Being relatively new to cross-language compilation, how are one language's class APIs typically translated into another? For example : [1,2,3].shuffle [turns into] => (function() { var __opal = Opal, self = __opal.top, __scope = __opal, nil = __opal.nil, __breaker = __opal.breaker, __slice = __opal.slice; return [1, 2, 3].$shuffle() })(); Of course, since JS arrays do not have a "shuffle" method, the output reads : TypeError: Object 1,2,3 has no method '$shuffle' Is the answer to simply use class/object methods that are present in both languages?

mossity 14y ago
Could probably also include something like Sugar.js or Underscore.js that tries to bring a lot of the missing syntactic sugar to JS.

vjeux 14y ago

Unfortunately their hash table uses Javascript objects. Therefore it does not behave exactly like Ruby. Eg: # Opal h = Hash.new h['0'] = 1 h[0] = 2 print h # {"0"=>2} # Ruby h = Hash.new h['0'] = 1 h[0] = 2 print h # {"0"=>1, 0=>2} It is very hard to reproduce those low level specifications without rebuilding everything from scratch sadly :(

lucian1900 14y ago
ECMA5 has real maps, which Opal could use. Some browsers support them already.

goggles99 14y ago

Can't those standards committees just do something right for once and create a standard for a vm that will run in the browser (a la Dartium)? Stop this monopoly and oppression of innovation!!!

jhrobert 14y ago

They lost me at the "nil" section. RubyScript is what we need => efficient code, à la coffeescript, with a Ruby syntax. There is some impedance mismatch between ruby & javascript semantics. Trying to hide this fact has a cost in terms of performance. I would love to have some ruby syntax as long as it does not compromize the speed of my code. There is a trend these days where syntax and semantics are becoming orthogonal, that's nice. Hence GoScript, PascalScript, PrologScript, CppScript, SmallScript... Thanks to sourcemaps the issue of the generated code readability has disappeared. Only the performance matters from now on.

SilasX 14y ago
>RubyScript is what we need => efficient code, à la coffeescript, with a Ruby syntax. Why not make a Ruby -> Coffeescript compiler, since they're a lot closer in the first place?