I'm not quite sure what's the purpose of either NoteCalc or Soulver, but I am currently getting acquainted with TeX - and from that perspective NoteCalc seems comically under-powered compared to what's achievable through plugging into the Lua(Meta)TeX engine with Lua, or with the Lua C API.
I'm not criticizing NoteCalc, rather I think somebody should create a lightweight note taking tool like that, I don't think it would be very difficult by leveraging the already existing TeX/ConTeXt/LMTX/LuaMetaTeX machinery, and it would blow the Soulver-like stuff out of the water. The main design problem could be deciding exactly where between ConTeXt and Soulver should the new tool/language lie power-wise, i.e., how much should it expose.
I'm not proposing using TeX directly, rather I'm proposing basing a new, simpler language on the Lua(Meta)TeX TeX engine, and probably also on ConTeXt/LMTX.
One of my primary design goal was something like that: "My mother should be able to use this tool to calculate/plan her vacation expenses". (My mother is older and not a tech guru you can guess :))
So the primary focus are on simple calculations with meaningful context and immediate feedback. Nothing fancy.
Though, beside that, I think it provides some nice features. E.g. the matrix creation/editing functionality was born because I could not find a simple tool to double check my rendering calculations with.
Yeah, I guess NoteCalc will be useful to many people, it's just that I'm noticing the sad lack of utilization of LuaTex (probably because people don't know it exists and exposes the power of TeX through Lua).
The targets of NoteCalc vs. the tool I'm proposing would be somewhat different, too, because LuaTex outputs primarily to PDF, and I don't know if it can produce HTML.
I'm not criticizing NoteCalc, rather I think somebody should create a lightweight note taking tool like that, I don't think it would be very difficult by leveraging the already existing TeX/ConTeXt/LMTX/LuaMetaTeX machinery, and it would blow the Soulver-like stuff out of the water. The main design problem could be deciding exactly where between ConTeXt and Soulver should the new tool/language lie power-wise, i.e., how much should it expose.
I'm not proposing using TeX directly, rather I'm proposing basing a new, simpler language on the Lua(Meta)TeX TeX engine, and probably also on ConTeXt/LMTX.