9 ms·

Can you connect to a running server or other running application, inspect live in memory data, change live in memory data, redefine functions and classes and ha

Can you connect to a running server or other running application, inspect live in memory data, change live in memory data, redefine functions and classes and have those changes take immediate effect without restarting the server or app? I think that is that is the big difference. It’s a triple edged sword bonded to a double barreled shotgun though, and the very antithesis of the idea of functional programming vs mutable state.

mathisfun123 3y ago
>Can you connect to a running server or other running application, inspect live in memory data, change live in memory data, redefine functions and classes and have those changes take immediate effect without restarting the server or app? The answer to all of these things, at least in python, is emphatically yes. I do this absolutely all the time. You can debug from one process to another if you've loaded the right hooks. You don't need to take my word for it or even try to do it; you just need to reason a fortiori: python can do it because it's an interpreter with a boxed calling convention and managed memory, just like lisp interpreters. It's amazing: people will die on this hill for some reason but lisp isn't some kind of mysterious system that was and continues to be beyond us mere mortal language/runtime designers. the good ideas in lisp were recognized as good ideas and then incorporated and improved upon.
- FPGAhacker 3y ago
  Can you give me some links? I don’t program clojure much these days but I’ve never found anything comparable in python.
  - mathisfun123 3y ago
    https://www.jetbrains.com/help/pycharm/remote-debugging-with-product.html https://www.jetbrains.com/help/pycharm/remote-debugging-with... I need to be very clear so that no one misunderstands: this is not proprietary pycharm functionality - this is all due to to sys.settrace and the pydev debug protocol https://www.pydev.org/manual_adv_remote_debugger.html https://www.pydev.org/manual_adv_remote_debugger.html So you can hook this up completely by yourself with some work but lucky for you and me pycharm makes it effortless.
- vkazanov 3y ago
  The answer to all these things should be "just doesn't work in practise", not for real programs anyways. Unlike Lisp, Python doesn't lean itself well to this mode of development. Primitive CLI-like tinkering, figuring out language features, calc-like usage - maybe. But not a single time in 15 years of doing Python across the industry I saw anybody using these features for serious program development, or live coding, or REPL-driven development.
  - mathisfun123 3y ago
    >Primitive CLI-like tinkering, figuring out language features, calc-like usage - maybe. But not a single time in 15 years of doing Python across the industry I saw anybody using these features for serious program development, or live coding, or REPL-driven development. I swear you people are like ostriches in the sand over this - Django, pytest, fastapi, pytorch, Jax, all use these features and more. I work on DL compilers and I use those features every day - python is a fantastic edsl host for whatever IR you can dream of. So just because you're in some sector/area/job that doesn't put you in contact with this kind of python dev doesn't mean it's not happening, doesn't mean that python doesn't support it, doesn't mean it's an accidentally supported API (as if such a thing could even be possible). Really what this convo is doing is underscoring for me how there really is nothing more to be learned from lisp - I had a lingering doubt that I'd missed some aspect but you guys are all repeating the same thing over and over. So thanks!
    - vkazanov 3y ago
      Listen, I've been on many sides: Lisp stuff, Python stuff, C stuff, etc. I don't think that "something has to be learned". Lisp has many good ideas, Python has good ideas. But REPL-driven development is not one of them. But let me explain. You see, it's not about how REPL in Python just does not allow something (even though it is rather primitive). Python makes it superhard to tweak things, even if you can change a certain variable in memory. Here's why. Think about Lisp programs, including OOP flavours. These fundamentally consist of 2 things: a list of functions + a list a variables. If you replace a function or a variable then every call will go through it. And that's it. You change a function - all calls to it will be routed through the new implementation. Because of REPL-centric culture of things people really do organise their programs around this style of development. Python was developed with an dynamic OOP idea in mind where everything is an object, everything is a reference. Endless references to references of references to references. It's a massive graph, including methods and functions and objects and classes and metaclasses. There is no single list of functions where you can just replace this name-to-implementation mapping. TL;DR Replacing a single reference doesn't change much in the general case. It does work in some cases. But that's not enough for people to rely on it as main development driver. Python fundamentally makes a different tradeoff than your average lisp.

mathisfun123 3y ago

>Can you connect to a running server or other running application, inspect live in memory data, change live in memory data, redefine functions and classes and have those changes take immediate effect without restarting the server or app? The answer to all of these things, at least in python, is emphatically yes. I do this absolutely all the time. You can debug from one process to another if you've loaded the right hooks. You don't need to take my word for it or even try to do it; you just need to reason a fortiori: python can do it because it's an interpreter with a boxed calling convention and managed memory, just like lisp interpreters. It's amazing: people will die on this hill for some reason but lisp isn't some kind of mysterious system that was and continues to be beyond us mere mortal language/runtime designers. the good ideas in lisp were recognized as good ideas and then incorporated and improved upon.

FPGAhacker 3y ago
Can you give me some links? I don’t program clojure much these days but I’ve never found anything comparable in python.
- mathisfun123 3y ago
  https://www.jetbrains.com/help/pycharm/remote-debugging-with-product.html https://www.jetbrains.com/help/pycharm/remote-debugging-with... I need to be very clear so that no one misunderstands: this is not proprietary pycharm functionality - this is all due to to sys.settrace and the pydev debug protocol https://www.pydev.org/manual_adv_remote_debugger.html https://www.pydev.org/manual_adv_remote_debugger.html So you can hook this up completely by yourself with some work but lucky for you and me pycharm makes it effortless.
vkazanov 3y ago
The answer to all these things should be "just doesn't work in practise", not for real programs anyways. Unlike Lisp, Python doesn't lean itself well to this mode of development. Primitive CLI-like tinkering, figuring out language features, calc-like usage - maybe. But not a single time in 15 years of doing Python across the industry I saw anybody using these features for serious program development, or live coding, or REPL-driven development.
- mathisfun123 3y ago
  >Primitive CLI-like tinkering, figuring out language features, calc-like usage - maybe. But not a single time in 15 years of doing Python across the industry I saw anybody using these features for serious program development, or live coding, or REPL-driven development. I swear you people are like ostriches in the sand over this - Django, pytest, fastapi, pytorch, Jax, all use these features and more. I work on DL compilers and I use those features every day - python is a fantastic edsl host for whatever IR you can dream of. So just because you're in some sector/area/job that doesn't put you in contact with this kind of python dev doesn't mean it's not happening, doesn't mean that python doesn't support it, doesn't mean it's an accidentally supported API (as if such a thing could even be possible). Really what this convo is doing is underscoring for me how there really is nothing more to be learned from lisp - I had a lingering doubt that I'd missed some aspect but you guys are all repeating the same thing over and over. So thanks!
  - vkazanov 3y ago
    Listen, I've been on many sides: Lisp stuff, Python stuff, C stuff, etc. I don't think that "something has to be learned". Lisp has many good ideas, Python has good ideas. But REPL-driven development is not one of them. But let me explain. You see, it's not about how REPL in Python just does not allow something (even though it is rather primitive). Python makes it superhard to tweak things, even if you can change a certain variable in memory. Here's why. Think about Lisp programs, including OOP flavours. These fundamentally consist of 2 things: a list of functions + a list a variables. If you replace a function or a variable then every call will go through it. And that's it. You change a function - all calls to it will be routed through the new implementation. Because of REPL-centric culture of things people really do organise their programs around this style of development. Python was developed with an dynamic OOP idea in mind where everything is an object, everything is a reference. Endless references to references of references to references. It's a massive graph, including methods and functions and objects and classes and metaclasses. There is no single list of functions where you can just replace this name-to-implementation mapping. TL;DR Replacing a single reference doesn't change much in the general case. It does work in some cases. But that's not enough for people to rely on it as main development driver. Python fundamentally makes a different tradeoff than your average lisp.