Fix CLI -L option that was unusable

[elia]

fixes #1510

[iliabylich]

👍

[bryanjhv]

It's still not fixed, I guess. Suppose the -L switch needs to generate the Opal library code and print it, but for now what I'm getting is empty output:

C:\Users\Bryan>opal -L

Maybe the problem is the :skip_opal_require (the implicit -O switch)? Or it's meant to work like that?

As a question: what does the :no_exit option means?

[elia]

@bryanjhv I agree that's debatable but I guess most of the time you'll want to use this to compile a lib for distribution and so made sense to me to ask for an explicit Opal require when they wanted that.

Although it's also true that an error should be displayed if there's nothing to compile… (great first pull-request! HINT HINT 😄)

C:\Users\Bryan>opal -L -r opal should do the job

[elia]

As a question: what does the :no_exit option means?

@bryanjhv by default the CLI will add a call to Kernel#exit at the end of the program that in turn will fire all Kernel#at_exit callbacks. Those callbacks are often used by some libraries to automatically run stuff just before exiting (e.g. both minitest and rspec use that in their autorun feature).

[bryanjhv]

Oh, didn't know what Kernel#exit thing.

And yes, you're right with the approach you took, that way we can build opal, opal-parser and others just with one command.