I'm not familiar with the algorithm and I don't see much explanation on the site (at least on mobile) but AFAICT this is turning parenthesized infix expressions into reverse Polish notation. In other words, it takes human-readable mathematical formulas and converts them into something a simple stack-based machine can compute in one forward pass.
It also appears that separate digits aren't interpreted as decimal numerals (i.e. (1)(3) is the sequence 1,3 and not 13) which can look a bit misleading.
> It also appears that separate digits aren't interpreted as decimal numerals (i.e. (1)(3) is the sequence 1,3 and not 13) which can look a bit misleading.
I didn't find it misleading; it says it operates on tokens, not digits.
Yeah, it's a parsing algorithm for parsing infix (etc.) expressions. If you've seen a parsing library refer to "precedence climbing" or "operator precedence parsing", it's doing this (or something very similar).
If you want to enter the number `13`, that should be one token, but there's no way to make a `13` token in this UI. You need to stick to single digits for this site to work correctly.
How would one typically implement this tokenization? Pre-pass on the input? My initial thought was to push an operand-terminator token when encountering an operator, but it was unclear to me whether it should be pushed to the stack or the output.
Hold up. you can't just have the train take the parenthesis off screen and hand wave away what happens to those cars. What happens when your forced to keep the garbage of a computation because you can't delete anything?
It also appears that separate digits aren't interpreted as decimal numerals (i.e. (1)(3) is the sequence 1,3 and not 13) which can look a bit misleading.
I didn't find it misleading; it says it operates on tokens, not digits.
If you want to enter the number `13`, that should be one token, but there's no way to make a `13` token in this UI. You need to stick to single digits for this site to work correctly.
(https://en.wikipedia.org/wiki/Reversible_computing)