These exist and are part of the fonts the article is talking about, though I've not seen it done for `==` because there's already a gap there. The ligatures for

These exist and are part of the fonts the article is talking about, though I've not seen it done for `==` because there's already a gap there. The ligatures for `==` in these fonts usually combine them to remove the space, but keeping it as two distinct characters. In JuliaMono/Fira Code, if you sequence `::`, the left colon in shifted slightly to the right and the right colon is shifted slightly to the left and both are scaled down slightly vertically. Try ::, :=, --, #!, ``, !!, ;; using Fira Code: https://www.programmingfonts.org/#firacode https://www.programmingfonts.org/#firacode These fonts can contain optional features which can be enabled/disabled dynamically by supporting editors. You could customize the behavior for specific languages and have the editor only show those features when you have the relevant language file loaded.