Special variables comparisons

[NotTheDr01ds]

At @132ikl's suggestion in #1860, I've added a few comparisons to other languages. I've done this as a VuePress Tab rather thana table so that we can use language-highlighting/code-blocks.

@132ikl - What do you think about this format?

[132ikl]

I'm not sure if the reduced ctrl-f-ability is made up for by a little syntax highlighting. The only one where the syntax highlighting does anything significant is the $env example. It would be difficult to find something like the equivalent to $0 since you can't ctrl-f for $0, so people might have to actual read through/scroll through in order to find what they're looking for. Not totally sure the best way to handle it is

[NotTheDr01ds]

Right - The Ctrl+F searchability is a problem, but I think most folks would figure that out from the index at the beginning.

The bigger problem, with either a table or tabs (but more so with a table) is that there's just no "1-for-1 mapping" in these.

For instance, $0 in Bash is not the same as any of our constructs.

In Bash:

• $0 in a source file will report the path to the interpreter.
• But running as a script works similar to our $env.PROCESS_PATH:
• And to add insult to injury, there's BASH_SOURCE (non-POSIX) which is an array where BASH_SOURCE[0] is closest to our PROCESS_PATH in both source and scripts.

Of course, we don't use an array to show the PROCESS_PATH when there's a parent caller (or callers) like BASH_SOURCE, but we probably should. But that means that neither ?0 nor BASH_SOURCE have a direct equivalent in Nushell.

PowerShell is equally incongruous to Nushell in these constructs.

And, for that reason, I think I'm going to give up trying to actually document this in any "succinct" form :-)

[fdncred]

I would've voted to just land it as a table or tabs. Some is better than none. Perfection is too high of a goal. Now, more people lose because this isn't there at all.

[NotTheDr01ds]

@fdncred I closed it because what I had in here was just wrong in most respects and, regardless, needs a fresh start.