6 ms·

Skulpt: client side Python without preprocessing

112 points by galfarragem 9y ago

meredydd 9y ago
Hi there! One of the Skulpt maintainers here. (Also founder of Anvil - https://anvil.works https://anvil.works. Never thought I'd have two projects on the front page at once!) Feel free to ask any questions about the gory internals and how it works. You might also enjoy my talk from PyCon US this summer, about how Skulpt compiles blocking Python code into non-blocking Javascript: https://anvil.works/blog/pycon-talk https://anvil.works/blog/pycon-talk
- primitivesuave 9y ago
  Thank you for building such a fantastic tool that has gotten so many more people coding in Python.
  - meredydd 9y ago
    Thank-you! It's definitely a team effort, including several educators as well as the teams from Trinket and Anvil (where I'm a cofounder). A particular shout-out for Albert-Jan Nijburg, who does some contracting for Trinket but donates a lot of his own time to the project. (I think we're top two contributors at the moment, but this varies a lot - we also get summer students who are very helpful.)
    - eah13 9y ago
      I can second this sentiment. Meredydd and Albert Jan have made a good deal of Skulpt's most technically interesting features (which in turn enable a more seamless user experience). I'm a cofounder of Trinket and we knew early on that this project was something we would use heavily and wanted to support. We support more languages now (including server side Python, Java, and with R coming soon) but our skulpt-based free Python trinket remains our most popular one. Our users have benefitted hugely from contributions by Meredydd, Albert Jan, Michael Ebert, Marie Chatfield, Scott Rixner, Brad Miller, and a whole bunch of other contributors. Go team!
- j_s 9y ago
  Yesterday's discussion demonstrated quite a bit of interest in using Python everywhere: Anvil: full stack web apps built only with Python | https://news.ycombinator.com/item?id=15584124 https://news.ycombinator.com/item?id=15584124 (Oct 2017, 195 comments) reply
- stuaxo 9y ago
  It would be good if there was some compatibility between Skulpt and Brython an equivalent to Pip that worked on both would be great.
eigengrau 9y ago
How does this compare to Brython (http://brython.info/ http://brython.info/), apart from missing the Python 3 support? Are there any custom bindings to the browser API?
- meredydd 9y ago
  I think it's mostly a difference in approach. Brython sets out to "replace Javascript with Python" as the language of scripting the Web. This means it has custom bindings to the browser API, supports writing Brython in <script> tags, uses slightly funky/un-Pythonic operators to do DOM manipulation, etc. Brython code can't block, to my knowledge (although the Python 3 async stuff makes that constraint much less painful these days). Skulpt is "a Python implementation in JS". It doesn't have built-in DOM bindings - it's typically used within a project like Anvil or Trinket which provides higher-level (and therefore more Pythonic) modules for display/input/IO. Skulpt code can block, which also helps keep those APIs simple. I guess my summary would be that Brython is great for scripting your HTML in Python rather than Javascript, but Skulpt is best for providing a Python runtime in your app. Does that make sense? (Of course, you'd have to ask a Brython developer for their take on it ;) )
  - azag0 9y ago
    Why the quotes around "Python implementation in JS"? Isn't it literally just that?
    - meredydd 9y ago
      They're quotes from each respective project's homepage :)
- albertjan 9y ago
  We are working on python3 support and skulpt does have a python3 mode which emulates the biggest differences between py2 and py3. (like from __future__ import). But it doesn't understand any of the new syntax added by python3 yet.
primitivesuave 9y ago
Many people, especially kids, will at some point encounter an online learning tool where you can just run Python in the browser. Chances are the underlying interpreter is Skulpt. A short list of examples: - https://pythonroom.com https://pythonroom.com: has a free online curriculum with more helpful error messages that kids can understand and real-time analytics for teachers - https://trinket.io https://trinket.io: handles Python, turtle graphics, and pygal charting in the browser - https://tynker.com https://tynker.com: their Python notebook feature uses Skulpt - http://interactivepython.org http://interactivepython.org: a popular open-source textbook that has excellent Parson's problems - http://codeskulptor.org http://codeskulptor.org: implements some custom Skulpt libraries that I haven't seen anywhere else - https://www.coursera.org/learn/interactive-python-1 https://www.coursera.org/learn/interactive-python-1: Coursera's interactive Python course That's just the ones I could remember off the top of my head. I truly believe this is one of the most impactful open-source projects of all time, especially if you consider the impact is has on kids (i.e. future computer scientists) that can use an excellent teaching language like Python directly in their web browser.
- closed 9y ago
  I work as an engineer at https://datacamp.com https://datacamp.com, and we run the code directly on a server, but I've always thought it would be interesting to try building interactive programming exercises with Skulpt.
  - peller 9y ago
    I've always wondered, how do you isolate/protect against people doing nefarious things in a setup like that?
    - mikkom 9y ago
      Virtual machine is probably the most common solution.
  - eah13 9y ago
    I'm a big fan of datacamp. You should definitely give this a try. It would be great to expand the reach of your lessons without the infrastructure overhead of every user hitting your server with their code. Hit up the skulpt dev listserve if you want some help. Or I'm at elliott@trinket.io. Plug: you could easily prototype this with Trinket embeds. Add #!/bin/python3 to the top of our Python (Skulpt) trinkets to get strict Py3 mode. Add data files via the + button (no directory support, so treat them as all in the local directory). Use the Share menu to get embed code. Paste. You've got your first interactive lesson. If your users like it, you can then decide whether and how to build skulpt in to the site.
amelius 9y ago
How long until we can compile Python to Web-assembly? EDIT: I just realized this can mean two things: 1. Compiling python source code to Web-assembly. 2. Compiling the python interpreter/compiler to Web-assembly.
- albertjan 9y ago
  (Contributor to skulpt and pypy.js here) That is a difficult question to ask and I think the original developer of pypy.js Ryan Kelly is most suited to answer it. There are some people that have tried feeding the asm.js from pypy.js to the asm.js -> wasm compiler. Which with a lot of fiddling may work for the non-jitted version. But if you want all the pypy speed you'll want to jit wasm to the browser. I would love to know if you can do synchronous calls in wasm.
  - meredydd 9y ago
    As Albert-Jan and I discussed at PyCon this weekend, the long-term future for Skulpt quite possibly involves compiling to WASM rather than Javascript. This is very unlikely to happen until every modern browser supports WASM. Neither Trinket's educational mission nor Anvil's "web apps for the world" mission are compatible with leaving users behind just because their workplace or school runs IE. The runtime can be remarkably small (Skulpt is 228kb minified and gzipped, including the standard library), so I think it's a feasible target. (Pypy.js is, of course, enormous!)
    - albertjan 9y ago
      What @meredydd means is, leaving the compiler written in javascript but emitting wasm, so compiling python into wasm with javascript. Too many compilers! :P
    - steveklabnik 9y ago
      > This is very unlikely to happen until every modern browser supports WASM WASM ships in every evergreen browser today: http://caniuse.com/#feat=wasm http://caniuse.com/#feat=wasm Only significant browser missing it is IE; only Edge has support.
eah13 9y ago
I'm a co-founder of Trinket and thought I'd explain why we chose Skulpt. Client-side execution lets you do visual things that would be slow and complicated (maybe practically impossible) if you ran them server side. Visual results are one of the most important motivators for students learning to code. Take our Sense HAT emulator, made in partnership with Raspberry Pi: https://trinket.io/sense-hat https://trinket.io/sense-hat This uses 3D CSS and SVG to make a virtual Raspberry Pi that you can rotate around. The Sense HAT has a gyroscope, accelerometer, etc that kids can actually program to respond to these movements. The alternative to this emulator was the Raspberry Pi Foundation sending boxes of computers to classrooms (which they still do). But the emulator makes this scalable while also synergizing with the computers: kids can download their code and run it on the real device if they want. The next phase in the project is letting kids run their code in space. Mission Zero uses the emulator to let European kids get their code run on one of the Raspberry Pis in orbit on the International Space Station: https://trinket.io/mission-zero https://trinket.io/mission-zero Skulpt makes this possible. Why not Brython or RapydScript? Theoretically, either could do most of this. Skulpt is designed for the needs of teachers and learners. Those projects have slightly different goals (making Python a web scripting language and providing a Pythonic way to write JS, respectively) which may make them a better fit for your project but we've found Skulpt to meet our users' needs the best. Our users are teachers and students in middle and high school, and some undergrads, who want to write, run, and share programs and websites as quickly and easily as possible. They need reasonable speed, fidelity to Python and lots of fun visuals. Turtle, Matplotlib, and now the Sense HAT emulator provide the visuals. Skulpt isn't perfect but it's got a great community and is getting better all the time. I think it's the clear best choice if your users are teaching or learning. And projects like Anvil (anvil.works) show how the project can work outside of education as well, in that case for non-specialist business analysts/ops people who would otherwise be stringing together spreadsheets.
cafogleman 9y ago
Hacker News strikes again. I'm receiving a '503 Over Quota' from the site right now.
- eah13 9y ago
  https://github.com/skulpt/skulpt https://github.com/skulpt/skulpt while you wait
  - tim333 9y ago
    Or the Google cache http://webcache.googleusercontent.com/search?q=cache:6RzAnjuDojsJ:www.skulpt.org/+&cd=1&hl=en&ct=clnk&gl=uk http://webcache.googleusercontent.com/search?q=cache:6RzAnju...
- albertjan 9y ago
  Oh nooo, I'll try and track down the person that has the creds to fix this :) ...
meredydd 9y ago
Urk! Albert-Jan is busily trying to wake someone up and get the site back up. Meanwhile: Archive link: http://archive.is/leOnD http://archive.is/leOnD GitHub: https://github.com/skulpt/skulpt https://github.com/skulpt/skulpt
deleted 9y ago
[deleted]
tim333 9y ago
Archive link if you get a 'Over Quota': https://web.archive.org/web/20171027212510/http://www.skulpt.org/ https://web.archive.org/web/20171027212510/http://www.skulpt...
albertjan 9y ago
We're back up! :)
- dpedu 9y ago
  The code won't run in my browser and I'm seeing Javascript errors. Hope this helps: https://i.imgur.com/gRLw9IW.png https://i.imgur.com/gRLw9IW.png
fulafel 9y ago
Standard Python is nicer for writing clients in many cases.
pgbovine 9y ago
creator of http://pythontutor.com/ http://pythontutor.com/ here ... skulpt is great and i know one of its maintainers quite well. one use case that's important is using it to distribute self-contained zero-install tutorials onto computers such as school machines and those in less-well-resourced parts of the world without good Internet access. you can deliver an HTML/CSS/JS zip file on a USB stick or CD-ROM and get lessons up and running even without Internet access. that said, though, one reason I haven't made the plunge to Skulpt and still choose to run Python server-side is that as students get more advanced, they will inevitably run into edge cases and other weird behavior where skulpt will not match CPython, and the error messages and other outputs they get will become inconsistent with expectations. that's why i still continue to run CPython server-side in a sandbox for http://pythontutor.com/ http://pythontutor.com/

112 points by galfarragem 9y ago

Hi there! One of the Skulpt maintainers here. (Also founder of Anvil - https://anvil.works https://anvil.works. Never thought I'd have two projects on the front page at once!) Feel free to ask any questions about the gory internals and how it works. You might also enjoy my talk from PyCon US this summer, about how Skulpt compiles blocking Python code into non-blocking Javascript: https://anvil.works/blog/pycon-talk https://anvil.works/blog/pycon-talk

primitivesuave 9y ago
Thank you for building such a fantastic tool that has gotten so many more people coding in Python.
- meredydd 9y ago
  Thank-you! It's definitely a team effort, including several educators as well as the teams from Trinket and Anvil (where I'm a cofounder). A particular shout-out for Albert-Jan Nijburg, who does some contracting for Trinket but donates a lot of his own time to the project. (I think we're top two contributors at the moment, but this varies a lot - we also get summer students who are very helpful.)
  - eah13 9y ago
    I can second this sentiment. Meredydd and Albert Jan have made a good deal of Skulpt's most technically interesting features (which in turn enable a more seamless user experience). I'm a cofounder of Trinket and we knew early on that this project was something we would use heavily and wanted to support. We support more languages now (including server side Python, Java, and with R coming soon) but our skulpt-based free Python trinket remains our most popular one. Our users have benefitted hugely from contributions by Meredydd, Albert Jan, Michael Ebert, Marie Chatfield, Scott Rixner, Brad Miller, and a whole bunch of other contributors. Go team!
j_s 9y ago
Yesterday's discussion demonstrated quite a bit of interest in using Python everywhere: Anvil: full stack web apps built only with Python | https://news.ycombinator.com/item?id=15584124 https://news.ycombinator.com/item?id=15584124 (Oct 2017, 195 comments) reply
stuaxo 9y ago
It would be good if there was some compatibility between Skulpt and Brython an equivalent to Pip that worked on both would be great.

eigengrau 9y ago

How does this compare to Brython (http://brython.info/ http://brython.info/), apart from missing the Python 3 support? Are there any custom bindings to the browser API?

meredydd 9y ago
I think it's mostly a difference in approach. Brython sets out to "replace Javascript with Python" as the language of scripting the Web. This means it has custom bindings to the browser API, supports writing Brython in <script> tags, uses slightly funky/un-Pythonic operators to do DOM manipulation, etc. Brython code can't block, to my knowledge (although the Python 3 async stuff makes that constraint much less painful these days). Skulpt is "a Python implementation in JS". It doesn't have built-in DOM bindings - it's typically used within a project like Anvil or Trinket which provides higher-level (and therefore more Pythonic) modules for display/input/IO. Skulpt code can block, which also helps keep those APIs simple. I guess my summary would be that Brython is great for scripting your HTML in Python rather than Javascript, but Skulpt is best for providing a Python runtime in your app. Does that make sense? (Of course, you'd have to ask a Brython developer for their take on it ;) )
- azag0 9y ago
  Why the quotes around "Python implementation in JS"? Isn't it literally just that?
  - meredydd 9y ago
    They're quotes from each respective project's homepage :)
albertjan 9y ago
We are working on python3 support and skulpt does have a python3 mode which emulates the biggest differences between py2 and py3. (like from __future__ import). But it doesn't understand any of the new syntax added by python3 yet.

primitivesuave 9y ago

Many people, especially kids, will at some point encounter an online learning tool where you can just run Python in the browser. Chances are the underlying interpreter is Skulpt. A short list of examples: - https://pythonroom.com https://pythonroom.com: has a free online curriculum with more helpful error messages that kids can understand and real-time analytics for teachers - https://trinket.io https://trinket.io: handles Python, turtle graphics, and pygal charting in the browser - https://tynker.com https://tynker.com: their Python notebook feature uses Skulpt - http://interactivepython.org http://interactivepython.org: a popular open-source textbook that has excellent Parson's problems - http://codeskulptor.org http://codeskulptor.org: implements some custom Skulpt libraries that I haven't seen anywhere else - https://www.coursera.org/learn/interactive-python-1 https://www.coursera.org/learn/interactive-python-1: Coursera's interactive Python course That's just the ones I could remember off the top of my head. I truly believe this is one of the most impactful open-source projects of all time, especially if you consider the impact is has on kids (i.e. future computer scientists) that can use an excellent teaching language like Python directly in their web browser.

closed 9y ago
I work as an engineer at https://datacamp.com https://datacamp.com, and we run the code directly on a server, but I've always thought it would be interesting to try building interactive programming exercises with Skulpt.
- peller 9y ago
  I've always wondered, how do you isolate/protect against people doing nefarious things in a setup like that?
  - mikkom 9y ago
    Virtual machine is probably the most common solution.
- eah13 9y ago
  I'm a big fan of datacamp. You should definitely give this a try. It would be great to expand the reach of your lessons without the infrastructure overhead of every user hitting your server with their code. Hit up the skulpt dev listserve if you want some help. Or I'm at elliott@trinket.io. Plug: you could easily prototype this with Trinket embeds. Add #!/bin/python3 to the top of our Python (Skulpt) trinkets to get strict Py3 mode. Add data files via the + button (no directory support, so treat them as all in the local directory). Use the Share menu to get embed code. Paste. You've got your first interactive lesson. If your users like it, you can then decide whether and how to build skulpt in to the site.

amelius 9y ago

How long until we can compile Python to Web-assembly? EDIT: I just realized this can mean two things: 1. Compiling python source code to Web-assembly. 2. Compiling the python interpreter/compiler to Web-assembly.

albertjan 9y ago
(Contributor to skulpt and pypy.js here) That is a difficult question to ask and I think the original developer of pypy.js Ryan Kelly is most suited to answer it. There are some people that have tried feeding the asm.js from pypy.js to the asm.js -> wasm compiler. Which with a lot of fiddling may work for the non-jitted version. But if you want all the pypy speed you'll want to jit wasm to the browser. I would love to know if you can do synchronous calls in wasm.
- meredydd 9y ago
  As Albert-Jan and I discussed at PyCon this weekend, the long-term future for Skulpt quite possibly involves compiling to WASM rather than Javascript. This is very unlikely to happen until every modern browser supports WASM. Neither Trinket's educational mission nor Anvil's "web apps for the world" mission are compatible with leaving users behind just because their workplace or school runs IE. The runtime can be remarkably small (Skulpt is 228kb minified and gzipped, including the standard library), so I think it's a feasible target. (Pypy.js is, of course, enormous!)
  - albertjan 9y ago
    What @meredydd means is, leaving the compiler written in javascript but emitting wasm, so compiling python into wasm with javascript. Too many compilers! :P
  - steveklabnik 9y ago
    > This is very unlikely to happen until every modern browser supports WASM WASM ships in every evergreen browser today: http://caniuse.com/#feat=wasm http://caniuse.com/#feat=wasm Only significant browser missing it is IE; only Edge has support.

eah13 9y ago

I'm a co-founder of Trinket and thought I'd explain why we chose Skulpt. Client-side execution lets you do visual things that would be slow and complicated (maybe practically impossible) if you ran them server side. Visual results are one of the most important motivators for students learning to code. Take our Sense HAT emulator, made in partnership with Raspberry Pi: https://trinket.io/sense-hat https://trinket.io/sense-hat This uses 3D CSS and SVG to make a virtual Raspberry Pi that you can rotate around. The Sense HAT has a gyroscope, accelerometer, etc that kids can actually program to respond to these movements. The alternative to this emulator was the Raspberry Pi Foundation sending boxes of computers to classrooms (which they still do). But the emulator makes this scalable while also synergizing with the computers: kids can download their code and run it on the real device if they want. The next phase in the project is letting kids run their code in space. Mission Zero uses the emulator to let European kids get their code run on one of the Raspberry Pis in orbit on the International Space Station: https://trinket.io/mission-zero https://trinket.io/mission-zero Skulpt makes this possible. Why not Brython or RapydScript? Theoretically, either could do most of this. Skulpt is designed for the needs of teachers and learners. Those projects have slightly different goals (making Python a web scripting language and providing a Pythonic way to write JS, respectively) which may make them a better fit for your project but we've found Skulpt to meet our users' needs the best. Our users are teachers and students in middle and high school, and some undergrads, who want to write, run, and share programs and websites as quickly and easily as possible. They need reasonable speed, fidelity to Python and lots of fun visuals. Turtle, Matplotlib, and now the Sense HAT emulator provide the visuals. Skulpt isn't perfect but it's got a great community and is getting better all the time. I think it's the clear best choice if your users are teaching or learning. And projects like Anvil (anvil.works) show how the project can work outside of education as well, in that case for non-specialist business analysts/ops people who would otherwise be stringing together spreadsheets.

cafogleman 9y ago

Hacker News strikes again. I'm receiving a '503 Over Quota' from the site right now.

eah13 9y ago
https://github.com/skulpt/skulpt https://github.com/skulpt/skulpt while you wait
- tim333 9y ago
  Or the Google cache http://webcache.googleusercontent.com/search?q=cache:6RzAnjuDojsJ:www.skulpt.org/+&cd=1&hl=en&ct=clnk&gl=uk http://webcache.googleusercontent.com/search?q=cache:6RzAnju...
albertjan 9y ago
Oh nooo, I'll try and track down the person that has the creds to fix this :) ...

meredydd 9y ago

Urk! Albert-Jan is busily trying to wake someone up and get the site back up. Meanwhile: Archive link: http://archive.is/leOnD http://archive.is/leOnD GitHub: https://github.com/skulpt/skulpt https://github.com/skulpt/skulpt

deleted 9y ago

[deleted]

tim333 9y ago

Archive link if you get a 'Over Quota': https://web.archive.org/web/20171027212510/http://www.skulpt.org/ https://web.archive.org/web/20171027212510/http://www.skulpt...

albertjan 9y ago

We're back up! :)

dpedu 9y ago
The code won't run in my browser and I'm seeing Javascript errors. Hope this helps: https://i.imgur.com/gRLw9IW.png https://i.imgur.com/gRLw9IW.png

fulafel 9y ago

Standard Python is nicer for writing clients in many cases.

pgbovine 9y ago

creator of http://pythontutor.com/ http://pythontutor.com/ here ... skulpt is great and i know one of its maintainers quite well. one use case that's important is using it to distribute self-contained zero-install tutorials onto computers such as school machines and those in less-well-resourced parts of the world without good Internet access. you can deliver an HTML/CSS/JS zip file on a USB stick or CD-ROM and get lessons up and running even without Internet access. that said, though, one reason I haven't made the plunge to Skulpt and still choose to run Python server-side is that as students get more advanced, they will inevitably run into edge cases and other weird behavior where skulpt will not match CPython, and the error messages and other outputs they get will become inconsistent with expectations. that's why i still continue to run CPython server-side in a sandbox for http://pythontutor.com/ http://pythontutor.com/