about mask
#1
I set the charset1 to ?d, then use the mask ?1?1?1?1## to describe keys start with 4 number and end with ##.

But if I want to use keys start with 4 number and end with ?1, what's the mask should be?

Thanks!
#2
Sorry, I find it.

A static letter is not indicated by a letter. An exception is if we want the static letter ? itself, which must be written as ??.