Improved versions of <C-a>, <C-x>, ~, g~, gu, and gU.

They are all implemented as operators, which allows for composing with motions/textobjecs, dot-repeating, and better undo.
Also, <C-a> and <C-x> are configurable and can "increment" and "decrement" not only numbers but words as well.

Configuration

If you don't want word toggling:

require'vis-toggler'

If you do:

require'vis-toggler'.config = require'vis-toggler.example'

Decimal and hexadecimal numbers are supported. If a number has leading zeros, its width is preserved.
The letter case of a hex number is either that of any existing letters, of letters in the last inc-/decremented hex number (if any), or of the base prefix (0x or 0X).

TODO

Improve <C-a>/<C-x> to support filetype-specific base notation and sets of ordinal words.
Introduce a buffer-local option to force a base for numbers that have no explicit prefix.