How to get a global available yasnippet snippet?

Question

How to create a yasnippet snippet which is available in all modes?
Lets say I have a function which evaluates the sexpr before the cursor and replaces is with its value, Link to code.
Also I caught me to regular use following sexpr (format "0x%x" ${1:number}) which prints a number in hex. Converting this into a snippet is easy, but:

Question: How can I tell yasnippet, to make it available in every major-mode?

Note: I read the question about multiple modes, but this seems to be much work and fiddling and I would have to create a directory in snippets-dir for every possible mode.