When opening a new file of certain types, I would like some boilerplate to be inserted. That is, when opening a buffer for a file that does not yet exist, insert some predefined text, optionally with some variable interpolation.

Things I can think of as use case:

• Insert some license text at the start
• Insert #IF_DEFINED_FOO_H directives in new C header files.
• Insert some basic targets in a new Makefile