9 ms·

Haskell as a JavaScript MVC framework

55 points by zygomega 11y ago

Detrus 11y ago
Github link is broken .org instead of .com https://github.com/tonyday567/mvc-todo https://github.com/tonyday567/mvc-todo
- cies 11y ago
  I did not even find the GitHub link... This brings you straight to the meat of the project: https://github.com/tonyday567/mvc-todo/tree/master/library/Todo https://github.com/tonyday567/mvc-todo/tree/master/library/T...
  - cies 11y ago
    And the actual Action sumtype is here: https://github.com/tonyday567/mvc-todo/blob/cb4bbb613aa31ba6d2da17db0d1c00a34c3581bd/library/Todo/Model.hs#L71 https://github.com/tonyday567/mvc-todo/blob/cb4bbb613aa31ba6...
bshimmin 11y ago
I'm sure it's very clever, but the result (http://tonyday567.github.io/static/index-auto.html http://tonyday567.github.io/static/index-auto.html) didn't work for me in Chrome (but did in Firefox). I suppose the unfortunate problem with this is that delivering it with an issue like that would mean that approximately 99.99% of the web developers out there would have no idea how to fix it (the generated JS is utterly incomprehensible, of course).
- a-saleh 11y ago
  That is something I was worried about, because afaik, ghcjs is still fairly experimental. But ability to use ghc's magic to produce javascript sounds aluring :-) I think, that if you could integrate source-map capabilities (haven't tried http://hackage.haskell.org/package/sourcemap http://hackage.haskell.org/package/sourcemap yet) it might make the debug process more bearable. But if you would be looking for haskell-like-language with more comprehensible to-javascript output, http://www.purescript.org/ http://www.purescript.org/ pleasantly suprised me (even though I had time to barely get past the hello world :-)
  - TazeTSchnitzel 11y ago
    I wanted to use PureScript, but the language is too unstable for me. They're getting rid of lists and pattern matching for them in the next version, for example, because they made the mistake of using JS's Array type.
    - codygman 11y ago
      Can you list some ways/reasons Purescript is too unstable for you? Maybe a link to the JS Array type mistake? I've used purescript for some semi-serious stuff before and didn't notice anything unstable.
      - TazeTSchnitzel 11y ago
        The next minor version of PureScript is changing everything. That's scary.
        purescript 11y ago
        s/minor/major
cies 11y ago
Good article, I really like the insight of how sum types can be used in MVC, and how the OO community is oblivious of this. Nice short read.
peferron 11y ago
I'm a big fan of static typing, including sum types. But can someone explain to me what's so great here? The highlight of the article is having a unique Action sum type instead of a myriad of separate functions. But the action still has to be processed by a myriad of separate equations (is that the correct Haskell term? Not familiar with the language): apply ClearCompleted tds = over todosItems (Map.filter (\x -> view itemStatus x /= Completed)) tds apply (DeleteItem x) tds = over todosItems (Map.delete x) tds apply (EditItem x) tds = set todosEditing (Just x) tds ... "Only one of the 68 frameworks defined an Action" is probably because it's simpler to directly call the right function, rather than over-engineering things with a short-lived intermediary representation. If actions need to "be serialized, recorded for later analytics, and generated automatically" then it makes much more sense. But this is a TODO sample app. YAGNI. And if we really need it, it's not like JS cannot do it: function apply(action, todos) { switch (action.type) { case 'ClearCompleted': return todos.filter(todo => !todo.completed); case 'DeleteItem': return todos.filter(todo => todo !== action.todo); ... } } The above has probably been done a billion times in one form or another. Of course it's not safe from typos in the case strings or missing cases, but that's a broader issue with JS in general, not specifically related to sum types. I'm not trying to shoot down Haskell here, I really wish someone will point to something I'm missing and make it click. But right now it just looks like over-engineering that JS could do but chooses not to. (Regarding footnote #4: Swift also has sum types and is fairly popular.)
- L8D 11y ago
  You're not missing anything. What you and the author are describing (in terms of pattern/architecture) has existed for quite a while but was widely popularized recently by Facebook's [Flux](https://facebook.github.io/flux https://facebook.github.io/flux). The author is either naive towards current state of the JavaScript landscape or their just being arrogant about what is actually unique to 'functional' programming.
  - christopherscot 11y ago
    Yep, was thinking the same exact thing when I saw "actions".
virtualwhys 11y ago
Yikes, 1,670KB for generated javascript alone, that's kind of a deal breaker. GHCJS has a ways to go methinks. Js_of_ocaml and Scala.js are far better suited for production use today as the type safety "tax" is much smaller (i.e. binary is at most 1/4 the size for equivalent functionality). EDIT: didn't realize you cannot yet call into Haskell from GHCJS, and even Haskell to GHCJS requires going through FFI[1] Meh, might as well use Fay or Haste if that's the caste. [1] http://stackoverflow.com/questions/29967135/how-to-call-haskell-from-javascript-with-ghcjs http://stackoverflow.com/questions/29967135/how-to-call-hask...
- TazeTSchnitzel 11y ago
  I quite like Haste for Haskell to JS compilation. Its output isn't too bloated.
  - codygman 11y ago
    Purescript (while not quite Haskell) also has very small output and is strict by default. There's also the very fun, informative, and productive "Purescript By Example"[0] book. 0: https://leanpub.com/purescript/read https://leanpub.com/purescript/read
FractalNerve 11y ago
I start to like Haskell and would enjoy learning to use it for the Web, but look at the size of it: http://i.imgur.com/kPHl4L7.png http://i.imgur.com/kPHl4L7.png 7834KB is way too large for just that, I'm afraid. I've 120Mbit/s, that's why it still loads fast, but I remember how slow, but fascinating surfing with 56K modem was.
- cschneid 11y ago
  I've explored ghcjs. I had a reasonable react based site down to ~400k after dead code removal and minification. Still biggish, but not multi-megabyte. The raw unoptimized code was in the several megabyte range though.
  - FractalNerve 11y ago
    I think it would be worth sharing that on a blog post submitted to HN. Sounds like a lot of work, maybe there are ways to automate that with a shell script or a Haskell program. 400KB is absolutely okay I think.
    - codygman 11y ago
      I agree, that would be awesome to study/emulate. Possibly use some of the techniques to make GHCJS programs smaller.
al2o3cr 11y ago
"It’s going to become much harder for haskell to avoid success" I have 100% faith in the Haskell community's ability to keep doing what they've been doing for years. ;)

55 points by zygomega 11y ago

Github link is broken .org instead of .com https://github.com/tonyday567/mvc-todo https://github.com/tonyday567/mvc-todo

cies 11y ago
I did not even find the GitHub link... This brings you straight to the meat of the project: https://github.com/tonyday567/mvc-todo/tree/master/library/Todo https://github.com/tonyday567/mvc-todo/tree/master/library/T...
- cies 11y ago
  And the actual Action sumtype is here: https://github.com/tonyday567/mvc-todo/blob/cb4bbb613aa31ba6d2da17db0d1c00a34c3581bd/library/Todo/Model.hs#L71 https://github.com/tonyday567/mvc-todo/blob/cb4bbb613aa31ba6...

bshimmin 11y ago

I'm sure it's very clever, but the result (http://tonyday567.github.io/static/index-auto.html http://tonyday567.github.io/static/index-auto.html) didn't work for me in Chrome (but did in Firefox). I suppose the unfortunate problem with this is that delivering it with an issue like that would mean that approximately 99.99% of the web developers out there would have no idea how to fix it (the generated JS is utterly incomprehensible, of course).

a-saleh 11y ago
That is something I was worried about, because afaik, ghcjs is still fairly experimental. But ability to use ghc's magic to produce javascript sounds aluring :-) I think, that if you could integrate source-map capabilities (haven't tried http://hackage.haskell.org/package/sourcemap http://hackage.haskell.org/package/sourcemap yet) it might make the debug process more bearable. But if you would be looking for haskell-like-language with more comprehensible to-javascript output, http://www.purescript.org/ http://www.purescript.org/ pleasantly suprised me (even though I had time to barely get past the hello world :-)
- TazeTSchnitzel 11y ago
  I wanted to use PureScript, but the language is too unstable for me. They're getting rid of lists and pattern matching for them in the next version, for example, because they made the mistake of using JS's Array type.
  - codygman 11y ago
    Can you list some ways/reasons Purescript is too unstable for you? Maybe a link to the JS Array type mistake? I've used purescript for some semi-serious stuff before and didn't notice anything unstable.
    - TazeTSchnitzel 11y ago
      The next minor version of PureScript is changing everything. That's scary.
      - purescript 11y ago
        s/minor/major

cies 11y ago

Good article, I really like the insight of how sum types can be used in MVC, and how the OO community is oblivious of this. Nice short read.

peferron 11y ago

I'm a big fan of static typing, including sum types. But can someone explain to me what's so great here? The highlight of the article is having a unique Action sum type instead of a myriad of separate functions. But the action still has to be processed by a myriad of separate equations (is that the correct Haskell term? Not familiar with the language): apply ClearCompleted tds = over todosItems (Map.filter (\x -> view itemStatus x /= Completed)) tds apply (DeleteItem x) tds = over todosItems (Map.delete x) tds apply (EditItem x) tds = set todosEditing (Just x) tds ... "Only one of the 68 frameworks defined an Action" is probably because it's simpler to directly call the right function, rather than over-engineering things with a short-lived intermediary representation. If actions need to "be serialized, recorded for later analytics, and generated automatically" then it makes much more sense. But this is a TODO sample app. YAGNI. And if we really need it, it's not like JS cannot do it: function apply(action, todos) { switch (action.type) { case 'ClearCompleted': return todos.filter(todo => !todo.completed); case 'DeleteItem': return todos.filter(todo => todo !== action.todo); ... } } The above has probably been done a billion times in one form or another. Of course it's not safe from typos in the case strings or missing cases, but that's a broader issue with JS in general, not specifically related to sum types. I'm not trying to shoot down Haskell here, I really wish someone will point to something I'm missing and make it click. But right now it just looks like over-engineering that JS could do but chooses not to. (Regarding footnote #4: Swift also has sum types and is fairly popular.)

L8D 11y ago
You're not missing anything. What you and the author are describing (in terms of pattern/architecture) has existed for quite a while but was widely popularized recently by Facebook's [Flux](https://facebook.github.io/flux https://facebook.github.io/flux). The author is either naive towards current state of the JavaScript landscape or their just being arrogant about what is actually unique to 'functional' programming.
- christopherscot 11y ago
  Yep, was thinking the same exact thing when I saw "actions".

virtualwhys 11y ago

Yikes, 1,670KB for generated javascript alone, that's kind of a deal breaker. GHCJS has a ways to go methinks. Js_of_ocaml and Scala.js are far better suited for production use today as the type safety "tax" is much smaller (i.e. binary is at most 1/4 the size for equivalent functionality). EDIT: didn't realize you cannot yet call into Haskell from GHCJS, and even Haskell to GHCJS requires going through FFI[1] Meh, might as well use Fay or Haste if that's the caste. [1] http://stackoverflow.com/questions/29967135/how-to-call-haskell-from-javascript-with-ghcjs http://stackoverflow.com/questions/29967135/how-to-call-hask...

TazeTSchnitzel 11y ago
I quite like Haste for Haskell to JS compilation. Its output isn't too bloated.
- codygman 11y ago
  Purescript (while not quite Haskell) also has very small output and is strict by default. There's also the very fun, informative, and productive "Purescript By Example"[0] book. 0: https://leanpub.com/purescript/read https://leanpub.com/purescript/read

FractalNerve 11y ago

I start to like Haskell and would enjoy learning to use it for the Web, but look at the size of it: http://i.imgur.com/kPHl4L7.png http://i.imgur.com/kPHl4L7.png 7834KB is way too large for just that, I'm afraid. I've 120Mbit/s, that's why it still loads fast, but I remember how slow, but fascinating surfing with 56K modem was.

cschneid 11y ago
I've explored ghcjs. I had a reasonable react based site down to ~400k after dead code removal and minification. Still biggish, but not multi-megabyte. The raw unoptimized code was in the several megabyte range though.
- FractalNerve 11y ago
  I think it would be worth sharing that on a blog post submitted to HN. Sounds like a lot of work, maybe there are ways to automate that with a shell script or a Haskell program. 400KB is absolutely okay I think.
  - codygman 11y ago
    I agree, that would be awesome to study/emulate. Possibly use some of the techniques to make GHCJS programs smaller.

al2o3cr 11y ago

"It’s going to become much harder for haskell to avoid success" I have 100% faith in the Haskell community's ability to keep doing what they've been doing for years. ;)