Show HN: Mathup – A simple MathML authoring tool
runarberg.github.io
runarberg.github.io
I've heard of AsciiMath before but hadn't ever had a chance to play with it, so I appreciated the live demo on the project website. One thing I noticed is that AsciiMath uses whitespace around operators to determine binding order.
For example (AsciiMath on left, TeX on right)
f(x) = x+1 / 2 ≡ f(x) = \frac{x + 1}{2}
f(x) = x + 1/2 ≡ f(x) = x + \frac{1}{2}
This seems fairly intuitive, but might not scale to large, complex equations as well as TeX's bracket syntax does. Nonetheless, I think I like it for simple equations.
Question for the author: you mention on the page that Mathup supports an input language inspired by AsciiMath [2]. What are the differences? Does Mathup accept a subset of AsciiMath, or are there cases where the syntax diverges? And if the latter is the case, what motivated devaiting from AsciiMath's syntax?
[0]: https://news.ycombinator.com/item?id=22582343
[1]: https://news.ycombinator.com/item?id=19347737
[2]: There's a typo in this phrase on your page, BTW: "insipired" has an extra "i"
There are some trivial differences: e.g. `bf` for boldface instead of AsciiMath’s `bb`; or the `.^` infix for overscripts instead of the `over` prefix. The matrix syntax is also quite different: AsciiMath uses nested brackets, while mathup uses row separators (`;` or `\n`). Most significant is the difference in grammar (you’ve noted the significant white space which is not a feature of AsciiMath).
You can see my attempt of writing down the grammar here[1]. However I’m very much a novice when it comes to compilers and lexical analysis, so this grammar is probably not accurate—in fact when I originally wrote Ascii2MathML I wasn’t even aware that I was writing a compiler. But in words, a set of tokens and operators with no internal white space tends to be grouped together. There are a few infixes (`/`, `^`, `_`, etc.) which generally take precedence but operate on a group of non spaced tokens if they are able to.
I originally wrote this because I wanted people that didn’t necessarily know TeX to be able to drop in a simple expression in comment threads and forums. I also liked to provide as much expressive power as possible, but I found AsciiMath lacking a little in expressiveness. The white space significance I found made writing a little easier, but in longer expressions it is a bit hard to use, but then again, this tool was always intended for smaller expressions anyway.
[1]: https://github.com/runarberg/mathup/blob/master/GRAMMAR