Code chunk fontification in Emacs noweb mode?

In noweb mode, I would like to make the doc chunks and code chunks easier to distinguish. I'm already using font-lock-mode, but it applies the same face to strings in R and strings in tex, so doesn't distinguish the code and doc chunks very well.

For example, a slightly different background color for the code chunks.

One possibility would be to define a new face for the minor mode of the code chunk, but then that face would also apply when editing a buffer in that mode.

Another possibility would be to create an overlay for the code chunks.

Also, somewhat related, org-mode can be configured to use different background colors for source blocks.

Update: I now use polymode to achive th开发者_JAVA技巧is.

You can use noweb-font-lock-mode from ESS to get syntax highlighting for both code and documentation chunks. I'd recommend you also use noweb-mode from ESS too, because it has some improvements.

One option would be mmm-mode, with which you can define regions that are in a different mode -- it also applies a face to the entire sub-mode region, which you can use to easily distinguish those regions within the parent file.

I personally use this for Ruby within IRB, Javascript and CSS within HTML etc. There's an example for javascript in my emacs config.

The MuMaMo extensions allows different rules for different parts of the file. Getting the nXhtml package will give you the mode and I think you can configure it to do what you want.