(In reply to comment #31)
> 1) In comment 29, Jesús Martínez Novo made a good suggestion to more widely
> publicize the new <lines> name before it gets committed.  
> A mailing list thread might be a good way to
> kick off this discussion.

I'll post one.

> 2) In the comments on the patch, '----' was brought up as the last remaining
> way that the current <lines> implementation differs from 'indent-pre'
> handling.
>  I'd like to resolve this discrepancy: I really really *really* don't want to
> complicate the parser more with Yet Another Slightly Different Way to handle
> preformatted content.

Let me expand a bit here: <poem> is designed for the treatment of poetry. I don't know what indent-pre was designed for, but one assumes it was intended for general-purpose, preformatted text, such as command line outputs and plain-text tables. The two use-cases are somewhat different.

I went through and found the following differences. There are probably many others.

* For some reason, indent-pre doesn't handle ----. Presumably this is so
  preformatted tables, etc (e.g. those copied out of the MySQL monitor)
  still appear correctly. This consideration is not relevant for <poem> and
  so ---- is parsed inside these tags. Indeed, ---- within <poem> is quite
  common at Wikisource.

* Indents using : are ignored within indent-pre (presumably because they
  don't make a whole lot of sense in a preformatted context). In <poem>,
  indents are handled specially (using a fixed-width <span> to give 1em
  indentation per : character), and line-initial spaces are transformed
  to &nbsp;, to cope with the special formatting of some poetry.

* Wikitext {| |} tables are available within <poem>, whereas indent-pre is
  aborted as soon as a table is found.

* Indent-pre formatting is aborted whenever a block-level tag is
  encountered on the line. Block-level formatting is, however, available
  inside <poem> (although this is only useful for stuff like <table>, since
  the appearance of tags like <p> is affected quite badly by the <pre>
  environment).

* Indent-pre is not available inside <blockquote>, for unclear reasons.
  <poem> works fine inside <blockquote>, just as anywhere else.

* <poem> allows the application of a custom class/ID/style. The use of a
  tag also allows extra attributes to be used - I have a patch in the works
  that adds line numbering support to <poem>, which makes use of several
  additional tag attributes (see bug 13644).

I don't think it is correct to speak of "resolving" these discrepancies. As you can see, most of them seem to exist for a reason, and most involve idiosyncrasies in the existing indent-pre behaviour, any changes to which would disrupt existing wikitext.

(Note, when I talk about <poem> above, I'm talking about the new implementation in Gerrit. The old extension sometimes does things differently.)

> 3) I'd also like to review the code coverage issues a little more, to ensure
> that we're sharing code (and CSS rules) to the maximum extent possible.

I think this is up to you, Scott, and others in the know.