[Ruby] Support code on same line as heredoc begin token

[wbond]

This will be merged right before we ship 3115 since it uses new functionality

[FichteFoll]

clear_scopes: 2

What does this do exactly?

Edit: Seems like it also accepts a boolean.

[wbond]

It removes N scopes from the scope name stack. Or you can pass true to clear the stack altogether, as used in #467.

In this case, it clears the two scopes added by the heredoc open token so that the code on the remainder of the line doesn't get highlighted like it is part of a string.

This could be useful for string interpolation, since we can remove the general string highlighting from the interpolated part.

[FichteFoll]

I assume this works like a meta scope is only valid for the current context? I like this. I also like that we can remove the string scope from interpolated sections like this.

[wbond]

Yes, this functions like meta_scope in that it only applies to the current context.

[trishume]

@wbond what does this mean? Why is this necessary? This context seems useless to me.

I'm trying to implement clear_scopes in https://github.com/trishume/syntect and the fact that this context looks useless to me suggests I might be misunderstanding the semantics of either clear_scopes or push/pop operations.

If you could explain to me why this is necessary I would really appreciate it. Also, what is a "push token" and why would clear_scopes apply to it?

[wbond]

clear_scopes is implemented in the same way as meta_scope in that it applies to the match the pushed, and to the match that pops.

The match that pushed is what I mean by "push token".

Without this, clear_scopes would clear the scope from the opening heredoc token, but we don't want that. I decided not to implement clear_scopes_content since this method can be used to emulate it.

[trishume]

Ok that makes sense, and in retrospect is explained in the docs, thanks for clearing up my confusion. Thanks!