There's a bug in my parser. Here's a debug UI showing it at a glance. The parse tree in the background is for the line the mouse pointer is hovering on. One fun thing is the couple of lines in the middle there. I reached for a notebook to scribble some equations for myself, but then realized all I wanted was to be able to draw the fraction line horizontally -- and I'm sitting in a tool that can do that. Using the tool to debug the tool 💥 (At least until I have no tools because I broke my tools using my tools. _Cross-link to a different thread._)