Creating a <span> over a range while preserving nesting

Ruby
1

While this is a rails-related question, it has more to do with ruby in
general.

The user selects a range by highlighting it. This is detected with
javascript and fed to ruby. I want to take this range and highlight it.

I’m doing that by adding around the region.
So that works ok, except that this often causes tag nesting problems.
What I want to do is intelligently add more tag pairs to preserve
nesting.

For example, the range:

this is a test that uses pretty
bizarre markup.

Should become:

this is a test
that uses pretty bizarre markup.

I’m not looking for someone to write the code for me (although if you
did, I wouldn’t complain); I just need someone to point me in the right
direction. Should I start from scratch with RegExes, or is there a
suitable library?

Thanks.

/burke

2

On Friday 10 August 2007 08:28:38 am Burke L. wrote:

I’m not looking for someone to write the code for me (although if you
did, I wouldn’t complain); I just need someone to point me in the right
direction. Should I start from scratch with RegExes, or is there a
suitable library?

Thanks.

/burke

You might look into Hpricot by _why or stdlib REXML.

3

The easy way to do this is to annotate all text runs in the selected
area; don’t try to figure
out if other tags are partly included or not.

In this example, I’ll use <A: to mean and :A> to
mean a that
closes an “anno” span. , , etc, stand for arbitrary
other tags. All text
is in lower case.

So, your example is

this is a:B> test <C:that <D:uses pretty:D>
bizarre:C> markup.

your example of what you wanted then can be written as:

<A:this is a:A>:B><A: test <C:that <D:uses pretty:D>
bizarre:C> markup.:A>

This is difficult because it requires some amount of parsing to figure
out
what markup is ‘complete’ (both start and end tags present) and what
isn’t
complete, then various processing to take that info into account. It’s a
pain
Instead, if you can accept markup like this:

<A:this is a:A>:B><A: test :A><C:<A:that :A><D:<A:uses
pretty:A>:D><A:bizarre:A>:C><A: markup.:A>

Then the algorithm for marking up the selection is simple; just find all
pieces of “real” text in selection
(i.e. not start or end tags), and wrap those pieces in <A: and :A>. This
is very easy to do with regular
expressions.

A potential problem is that you may end up with ‘gaps’ in your
highlighting. On the other hand,
you’re less likely to run into weird CSS problems.

Cheers,
Ken