vim: associate extension with language

Question

I have gvim 7.2, it recognizes .d files and highlights it correctly according to the syntax of the D programming language. However, .di files are not recognized as D files, and no highlighting is present.

How do I let vim highlight .di files according to D language?

Answer 1

http://vimdoc.sourceforge.net/htmldoc/filetype.html has the (gritty) detail on filetypes. You can modify the associated plugins by editing your vimrc. look for the rule *.d, and copy/paste that line changing it to *.di

I've not used gvim, so there may be an easier way I'm unaware of

Answer 2

This ought to do it in .vimrc:

au BufNewFile,BufRead *.di setlocal ft=d

There are probably other ways, too.