The digraph feature in vim allows entering control codes and dicrital marks that would normally be impossible to type on an ascii keyboard.

Listing

:dig[raphs][!]          Show currently defined digraphs.
                        With [!] headers are used to make it a bit easier to
                        find a specific character.

Using

There are two methods to enter digraphs:

CTRL-K {char1} {char2}
{char1} <BS> {char2}

The first is always available; the second only when the digraph option is set.

Common digraphs

²       2S      superscript two
Ā       A-      complement of A
∈       (-      element of
∉       !(      not element of
∋       -)      contains as member
⊆       (_      subset of or equal to
⊊       (~      proper subset of
⊇       )_      superset of or equal to
⊋       )~      proper superset of
∅       /0      empty set
∩       (U      intersection
∪       )U      union

™       TM      trade mark sign

ā       a-      mandarin first tone
á       a'      mandarin second tone
ǎ       a<      mandarin third tone
à       a`      mandarin forth tone

Creating new digraph's (from lua)

vim.api.nvim_command('dig (~ 8842')
vim.api.nvim_command('dig )~ 8843')
vim.api.nvim_command('dig !( 8713')