Support automated space insertion with the Pangu library.

[cmpute]

Pangu is a module that automatically insert spaces between CJK characters and Latin characters, which is very useful to increase readability of some text mixed with CJK and Latin characters. It has been implemented in several languages including Go and JS.

I posted a feature request for this in the Hugo repo (gohugoio/hugo#10617), and I agreed on that this should be implemented in the renderer side. Therefore, I propose to add an CJK extension to allow automatic space insertion with the Pangu library.

[yuin]

README says "Depends only on standard libraries."
So this is unlikely to happen.

[cmpute]

The Go implementation is self-contained (without third-party dependencies), and it has only 147 lines. Do you consider directly porting the source code in? The licenses are also compatible (both MIT).

[yuin]

It seams that the implementation has problems:

• It seems using a lot of regexp. Go's regexp performance is poor for common usecases(but stable for text length). goldmark avoids regexp as much as possible.
• Markdown processing is not equal to simple text processing. Parser parses markdown to AST, then text are spitted into peace of segments.
  • ie: こんにちは[**Tomさん**](http://example.com/tom)ごきげんいかがですか -> [Text(こんにちわ),Link(label=Empasis(Text(Tomさん)), url="http://example.com/tom"), Text(ごきげんいかがですか)]
  • So simple regexp approach will not be worked for this kind of structure.

[cmpute]

Ok thanks for the explanation. I still wish this feature could be supported, but it seems like there is an amount of required work to implement the spacing feature. Again, thanks for your great work on this project!

[cmpute]

Is regexp a deal breaker for this functionality? If it's acceptable when used only in this functionality, I do want to have a try to implement this feature.

[yuin]

First of all, we should consider whether this functionalities are possible to implement as an extension.
If so, implementation details are not an issue.