I run this command to search for symbols but it often does not have the symbol I require

vimhelp digraph-table
·	.M	0xb7	183	MIDDLE DOT
⇔	==	21D4	8660	LEFT RIGHT DOUBLE ARROW
∀	FA	2200	8704	FOR ALL
∂	dP	2202	8706	PARTIAL DIFFERENTIAL
∃	TE	2203	8707	THERE EXISTS
∅	/0	2205	8709	EMPTY SET
∆	DE	2206	8710	INCREMENT
∇	NB	2207	8711	NABLA
∈	(-	2208	8712	ELEMENT OF
∋	-)	220B	8715	CONTAINS AS MEMBER
∏	*P	220F	8719	N-ARY PRODUCT `
∑	+Z	2211	8721	N-ARY SUMMATION `
≤	=<	2264	8804	LESS-THAN OR EQUAL TO
≥	>=	2265	8805	GREATER-THAN OR EQUAL TO
≪	<*	226A	8810	MUCH LESS-THAN
≫	*>	226B	8811	MUCH GREATER-THAN

I had to Google for these symbols as they were not in the list

  • List of symbols we wish to make into digraphs
    • ℕ - double-struck capital N
    • ℤ - Zahlen - double-struck capital Z
    • ℝ - double-struck capital R

Run the unicode program to find the decimal ID for each symbol we want

unicode ℕ
unicode ℤ
unicode ℝ

Add them to the vim digraph table

Vim uses the decimal value of the symbol.

  • This is the code to be added to vimrc

    digr ZZ 8484
    digr NN 8469
    digr RR 8477

Add them to evil-mode for emacs

emacs uses the hex value.

The unicode command doesn’t provide the hex so we must convert them.

p 8484 | dec2bin
  • This is the code to add to your .emacs

    (setq evil-digraphs-table-user '(((?N ?N) . ?\x2115)
                                     ((?Z ?Z) . ?\x2124)))