"${empty:-}" evaluates to nothing rather than empty string about oil

[andychu]

OK I fixed it... it's kind of weird there are 3 clauses to the conditional, but I think this is the right solution. The idea is to do more work at parse time, which might look messy, but then you get a fairly clean AST to execute.

At runtime you don't want to worry about this kind of stuff.

That is very different than bash which has no distinction between parse time and runtime for what's inside ${}. It's all done at runtime.

One possible fix to the location info problem I mentioned is to add a new node DummyEmptyPart instead of reusing SingleQuotedPart. That's probably the right solution come to think of it...

[andychu]

Closing since it's fixed, feel free to file more issues about error messages and so forth.

Also I will file one about spec tests in a known environment.

[andychu]

Oops, I just realized ${empty:-} without quotes is now broken... thinking about how to fix this...