Hello. Recently I have faced the “world age problem” several times. That means, after searching for my problems, this website came up with themes like “world age workaround” or “How to Bypass the World Age Problem”. I am not a computer scientist, so maybe this is a stupid question, but I have not …

How to Bypass the World Age Problem does have some information Seems to be to do with redeclaring functions and/or the order they are defined in, and using eval / @eval

Thank you for this information. I’ve read some pages and maybe, I get an idea. But I need a starting point to understand this issue completely and want to be sure, that I’ve understood this correctly. Can someone please revise or confirm the following? Every compilation of a function gets a “time …

The reason for worlds is because of optimizations. If functions can be defined (and redefined) at arbitrary points (and instantly take effect), then that would limit the possible optimizations that can be made. Therefore, new functions are only made visible to the system (become usable) after hittin…

You might also want to share a minimal working example (MWE) of your code. In my experience, world age issues are rather uncommon and perhaps you are using eval in cases where you shouldn’t.

Thank you very much for your answer, kristoffer.carlsson. This helps me a lot. I will take a closer look at this whole theme on the weekend; especially at your link, mbauman. If errors related to world age continue to appear, I will let you know and share my code. At the moment, I just want to und…

I would add that requiring modifications to dispatch to take effect immediately is one of those classic behaviors in dynamic languages that makes them hard/impossible to compile without heroic efforts (along with reified local scopes, the ability to add state to objects dynamically at any point, etc…

Seel also here for a detailed explanation , and here for an explanation of invokelatest . It would be nice to have something about this in the manual at some point…

This is a great explanation, thank you! Would you be so kind as to elaborate on “after hitting toplevel” please? What does that mean? Thanks

Top level is where the execution hits global scope for example if the code below was a file that we run, I’ve indicated the places where “top level” is reached <-------------- top level module M <-------------- top level function f(x) return x end <-------------- top level struct Bar a::In…

World Age Problem Explanation

General Usage

mbauman March 15, 2018, 1:26pm 5

Check out "running in world age X, while current world is Y" errors for another explanation.

2 Likes

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World Age Problem Explanation

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