This is the first time I've seen TODO as a ligature, and I am really into the idea. Is this something you can add to existing fonts? Does anyone have any recommendation for a good programming font that does this?
Fira Code supports stylistic sets, so you can actually configure whether == and === (and != and !==) do that, and leave weirder ligatures out of the defaults. In VS Code, for example, you would change editor.fontLigatures from true to "'ss08'" to make them still ligate together, but with breaks between the = signs. I use ss06 to make backslashes faded when they're used to escape other characters.
Glad you like it, I've never seen it in a font before so I am unsure if there are any others that add it in. I've definitely appreciated the ligature as I use the font, but I did wonder if others would find it annoying
I could do without operators being condensed into ligatures, but that's just me. The gigantic triple equals strikes fear into my C programmer heart