Tomas Mejia

It's definitely intended that unknown identifiers be kept for `execute` to take care of. Unless you pass the `base_instance` to `parse` as well, it's fine as is.

> Your changes are split across 6 commits, you will need to [squash](https://docs.godotengine.org/en/latest/contributing/workflow/pr_workflow.html#the-interactive-rebase) them into 1. > > I also noticed that this PR does not contain [test cases](https://github.com/godotengine/godot/blob/master/tests/core/math/test_expression.h) for...

Thank you so much for all of your patience! I am still learning how to use git and how to manage the PR policies and whatnot, but I think I...

> Your PR seems to fail some of the existing test cases as well. Some stuff in there needs to be fixed, e.g. scientific number notation, some other failing cases...