What's the thing with global variables?

From what I've tried, using the global variables like this

var some_global_var: String = "Hey!"

fn main():
    print(some_global_var)

var some_global_var: String = "Hey!"

fn main():
    print(some_global_var)

works when you just run your code, but doesn't work in compiled executables. I've seen some folks mentioning this here on this server, but I can't seem to find any relevant docs on this, as well as I don't understand whether it's a bug, or am I supposed to work with global variables somehow differently. Any info on this would help, thanks!

4 Replies

toasty•2w ago

They’ve said that it results in undefined behavior, so it’s not really supported at this time. Hopefully soon! You can define top level constants using alias though

Tyoma Makeev•2w ago

Ah, ok, thanks for the clarification! Is there a bug for this or something else where I coud track the progress on this (assuming it's planned)?

Ryulord•2w ago

https://github.com/modularml/mojo/issues/1573

GitHub

Global variables are not fully supported · Issue #1573 · modularml/...

Bug description run this code: from python import Python var mod_global :PythonObject = None fn main() raises: let mod_xml : PythonObject = Python.import_module("lxml") # let mod_global :...

Tyoma Makeev•2w ago

great, thanks!

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What's the thing with global variables?