s&r for paired tags

[eschwartz]

Originally Posted by phossler

@eschwartz--



1. Can you explain how the negative look ahead works, including breaking down the pieces of the RE?

2. Many times when I'm cleaning an epub, removing unneeded 'class=" ... " ' in <span class="..."> I'll eventually end up with a lot of <span>.....</span> constructs. It appears that your RE is better than the more simplistic RE I was using to just remove them

Thanks

This website has a very good regex explanation, which is how I learned about it.
http://www.regular-expressions.info/lookaround.html

They provide a thorough explanation, and break down the examples.

For my example:

<span class="none2">((?:(?!<span).)*?)</span>

Search for

<span class="none2">inner text</span>

"inner text" itself is a little more complicated, though:

((?:(?!<span).)*?)

We capture everything as "\1" --inside is

(?:(?!<span).)*?

The main search (finally ) is:

(?:(?!<span).)

a non-capturing group, which is repeated zero or more times -- yes, we can repeat whole groups.
(plus a confusing "?" which is redundant (the start already makes it optional) and I seem to have copied it randomly from the original source .)

This group contains the negative lookahead (a zero-length assertion)

(?!<span)

which searches for the non-existence of "<span", followed by a dot-matches-all.

So, putting it all back together, the dot-match-all must be preceded by the negative lookahead, and this "any character other than part of a span tag" is then grouped and repeated zero or more times, then captured as "\1" to produce the "inner text" which should be saved from in between the span.

[JSWolf]

Is there a way to find a proper span when the code looks like

<p><span class="italics"><span class="smallcaps">This is italics smallcaps</span></span> <span class="bold>This is bold</span></p>

Can all three of the span pairs be found correctly using regex?

[eschwartz]

Originally Posted by JSWolf

Is there a way to find a proper span when the code looks like

Can all three of the span pairs be found correctly using regex?

Yes -- by specifying all of them. You'd have to know ahead of time how many there are.

[JSWolf]

Originally Posted by eschwartz

Yes -- by specifying all of them. You'd have to know ahead of time how many there are.

But that's the problem. You don't know ahead of time. You don't know how many or which ones. The idea is for regex to get it right which it doesn't. This is why we need an update to regex to allow us to have more control so we can do things like this. Regex should be able to say I want the next instance of </span> after the <span>. But we cannot do it. So regex should be updated to handle such things.

[cybmole]

Originally Posted by JSWolf

... Regex should be able to say I want the next instance of </span> after the <span>. But we cannot do it. So regex should be updated to handle such things.

surely that is almost trivially easy to write regex for- just write a lazy find expression.

I'd do it for you but I'm feeling a lttle lazy myself , right now wasn't one presented a few posts back ?

[Tex2002ans]

Originally Posted by JSWolf

This is why we need an update to regex to allow us to have more control so we can do things like this. Regex should be able to say I want the next instance of </span> after the <span>. But we cannot do it. So regex should be updated to handle such things.

Just because Regex can't do something it wasn't designed to do, doesn't mean Regex must be updated!

You would be using the wrong tool for the job, and what you want is a parser!

Here is some discussion on why Regex isn't recommended for parsing HTML:

https://stackoverflow.com/questions/...e-html-why-not

There is a reason why they are separate beasts.

[eschwartz]

Originally Posted by Tex2002ans

Just because Regex can't do something it wasn't designed to do, doesn't mean Regex must be updated!

You would be using the wrong tool for the job, and what you want is a parser!

Here is some discussion on why Regex isn't recommended for parsing HTML:

https://stackoverflow.com/questions/...e-html-why-not

There is a reason why they are separate beasts.

Yep, basically. Although there are some things you can do with lookaround, like my example. Given a specific known quantity (what regex is for) it will clobber all those nested spans on repeating runs.

Also fun link: http://stackoverflow.com/questions/6...lanation-in-la

The second answer does a good job explaining why regex is a bad tool for html parsing (and when it is a good tool!).

[phossler]

Originally Posted by PeterT

You might also check out the forked version of ePub Clean plugin for calibre that has some support for removing SPANs

I can find a Modify ePub PI, but no ePubClean PI

Modify ePub does not seem to have any options to clean unneeded tags etc.

[PeterT]

You need to look for the version posted by Reverend Bob.

[phossler]

Originally Posted by PeterT

You need to look for the version posted by Reverend Bob.

Sorry, but I still don't see anything close to that title or by Rev Bob.

Can you point me in the right direction please?

[eschwartz]

Originally Posted by phossler

Sorry, but I still don't see anything close to that title or by Rev Bob.

Can you point me in the right direction please?

It's not indexed -- it is in the Modify EPUB thread, and will eventually get merged back into the main PI, once Rev. Bob finishes testing it. See here for the latest beta: https://www.mobileread.com/forums/sho...78#post2880178

[phossler]

Originally Posted by eschwartz

It's not indexed -- it is in the Modify EPUB thread, and will eventually get merged back into the main PI, once Rev. Bob finishes testing it. See here for the latest beta: https://www.mobileread.com/forums/sho...78#post2880178

Ahh - thanks

I only had a chance to browse the last 5 or 6 of the 53 pages, but it looks like a very useful tool

Is there a brief description of the options and features that will be in the final version?

[eschwartz]

Buried, "somewhere".

It should add methods for

• removing certain spans created by Kobo for KEPUB that do nothing besides provide bookmarking abilities,
• removing <span>content</span> paris, which obviously do nothing,

and a few other things I forget.

[BetterRed]

Originally Posted by eschwartz

Buried, "somewhere".

Hopefully it will be exhumed and incorporated into .../calibre/plugins/Modify ePub Help.htm

BR

[eschwartz]

Originally Posted by BetterRed

Hopefully it will be exhumed and incorporated into .../calibre/plugins/Modify ePub Help.htm

BR

I have no idea, I don't have either one installed.