Safe Access Operator

[oldwomanjosiah]

Description

• closes [FEATURE] Safe Access Syntax #565
• Updates the elvis operator ?: to treat a JSON Null the same as the empty string ""
  This was done, as that is what is returned by an object access for an undefined field.

Usage

:label { labels?.workspaces?.one ?: "Workspace One" }

with some varable labels. labels.workspaces.one ?: "Workspace One" would error if:

• labels was not an object
• labels.workspaces was not an object

It would also act strangely if either any of labels, .workspaces, or .one were Null, as the elvis operator treated that as "already existing".

Diffs containing full example of usage

Additional Notes

It might also make sense to allow for opt-object?.[key-expr], but that is left for a follow-up.

Checklist

• All widgets I've added are correctly documented.
• I added my changes to CHANGELOG.md, if appropriate.
• The documentation in the docs/content/main directory has been adjusted to reflect my changes.
• I used cargo fmt to automatically format all code before committing

[elkowar]

thanks a lot for your work! This is cool!