What is a simple way to combine two Emacs major modes, or to change an existing mode?

In Emacs, I'm working with a file that is a hybrid of two languages.

Question 1: Is there a simple way to write a major mode file that combines two major modes?

Details:

• The language is called "开发者_JAVA技巧brew" (not the "BREW" of "Binary Runtime Environment for Wireless").

• brew is made up of the languages R and Latex, whose modes are R-mode and latex-mode.

• The R code appears between the tags <% and %>. Everything else is Latex.

• How can I write a brew-mode.el file? (Or is one already available?)

One idea, which I got from this posting, is to use Latex mode, and treat the code of the form <% ... %> as a comment.

A number of folks have written solutions enabling you to use multiple major modes at once. See the Emacs Wiki for Multiple Modes. I personally have no experience with them and cannot recommend one over another.