Question

I’ve seen hints on how to search for unicode characters in vim using :help regexp and \%u , but I have not been able to figure out how to replace text with a hex-defined unicode character.

The particular situation is that a DefaultKeyBindings.dict needs comments that will print the character mapped in that line in a comment.

Begin:

blah blah...\U2234  

Command:

:s/\v.*\\U(\d{4})/& \/\*\\\\%u\1 \*\/  

Result:

blah blah...\U2234 /*\%u2234 */  

Goal:

blah blah...\U2234 /* ∴ */

Answer 1

You need to convert the string representation of the hexadecimal Unicode value into the actual character represented by it. This is a task for nr2char(), which can be embedded into the substitution via :help sub-replace-expression:

:substitute+\v.*\\U(\d{4})\zs+\='/* '.nr2char(str2nr(submatch(1),16)).' */'+

Protip: Use a different separator (I chose + over /), then you don’t need to escape.