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examples please, because so far i have only seen this from common lisp and smalltalk. there is also pike where i can reload classes or objects at runtime, thus

by em-bee 3y ago

examples please, because so far i have only seen this from common lisp and smalltalk. there is also pike where i can reload classes or objects at runtime, thus avoiding a full restart, but it's not as closely integrated as in smalltalk and you actually have to build your app in a way that allows you to do that.

lenkite 3y ago
Java supports live debugging and profiling.
- db48x 3y ago
  But that’s not the same thing at all. If you’re debugging an exception in Java, you cannot continue execution as if the exception had not been thrown at all. With Common Lisp’s condition system you can.
  - lenkite 3y ago
    Umm.. you can throw an exception, you can return to previous call frame, you can reload modified classes. If you want unlimited code modification, you can use dcevm https://github.com/dcevm/dcevm https://github.com/dcevm/dcevm https://www.jetbrains.com/help/idea/altering-the-program-s-execution-flow.html https://www.jetbrains.com/help/idea/altering-the-program-s-e...
  - regularfry 3y ago
    The question was whether you can debug a live service while it's handling live traffic. Not whether you can fix it. Java can definitely do the former, and definitely can't do the latter.
    - em-bee 3y ago
      my question specifically was which languages/runtimes allow you to actually make changes to the code in a live process without restarting it.
      - deleted 3y ago
        [deleted]
      - regularfry 3y ago
        Your question moved the goalposts. Making change to a running system wasn't part of db48x's claim to which dleslie responded. It was explicitly excluded, in fact.
        em-bee 3y ago
        ok, fair, but what i am asking about is a feature of common lisp (and smalltalk or pike), so i didn't pay attention to the exclusion. that was not deliberate. my bad. (maybe you could say i moved the goalpost back to the original topic)
dleslie 3y ago
JavaScript immediately comes to mind.
- em-bee 3y ago
  how do you do it? in the browsers debugger? maybe, but that is not integrated with your actual source files, so you have to be careful to track your changes and copy them to your source. that may help in some cases but isn't really practical.
pjc50 3y ago
It's not always usable, but Visual Studio offers this for C# (works most of the time) or C++ (works in fewer cases because of the terrible header model)
- em-bee 3y ago
  but you wouldn't be able to use that on your production server, would you?

by em-bee 3y ago

lenkite 3y ago

Java supports live debugging and profiling.

db48x 3y ago
But that’s not the same thing at all. If you’re debugging an exception in Java, you cannot continue execution as if the exception had not been thrown at all. With Common Lisp’s condition system you can.
- lenkite 3y ago
  Umm.. you can throw an exception, you can return to previous call frame, you can reload modified classes. If you want unlimited code modification, you can use dcevm https://github.com/dcevm/dcevm https://github.com/dcevm/dcevm https://www.jetbrains.com/help/idea/altering-the-program-s-execution-flow.html https://www.jetbrains.com/help/idea/altering-the-program-s-e...
- regularfry 3y ago
  The question was whether you can debug a live service while it's handling live traffic. Not whether you can fix it. Java can definitely do the former, and definitely can't do the latter.
  - em-bee 3y ago
    my question specifically was which languages/runtimes allow you to actually make changes to the code in a live process without restarting it.
    - deleted 3y ago
      [deleted]
    - regularfry 3y ago
      Your question moved the goalposts. Making change to a running system wasn't part of db48x's claim to which dleslie responded. It was explicitly excluded, in fact.
      - em-bee 3y ago
        ok, fair, but what i am asking about is a feature of common lisp (and smalltalk or pike), so i didn't pay attention to the exclusion. that was not deliberate. my bad. (maybe you could say i moved the goalpost back to the original topic)

dleslie 3y ago

JavaScript immediately comes to mind.

em-bee 3y ago
how do you do it? in the browsers debugger? maybe, but that is not integrated with your actual source files, so you have to be careful to track your changes and copy them to your source. that may help in some cases but isn't really practical.

pjc50 3y ago

It's not always usable, but Visual Studio offers this for C# (works most of the time) or C++ (works in fewer cases because of the terrible header model)

em-bee 3y ago
but you wouldn't be able to use that on your production server, would you?