It would appear as though the repo owner is no longer accepting new issues (the "Submit new Issue" button is greyed out). So, in lieu of submitting a new issue,

It would appear as though the repo owner is no longer accepting new issues (the "Submit new Issue" button is greyed out). So, in lieu of submitting a new issue, here is the issue that I would have opened (in Markdown): Looking through the README, the first thing that made me balk was the fact that the limit of `1/x` as `x->0` is not infinity. The limit doesn't exist! However: * The limit as x goes to zero from the right of `1/x` is infinity, and * The limit as x goes to zero from the left of `1/x` is negative infinity. So, to quickly determine whether or not this was just a documentation issue, I installed Hilbert ([and eventually succeeded](https://github.com/gogotanaka/Hilbert/pull/68 https://github.com/gogotanaka/Hilbert/pull/68 )) and tried to discover the syntax for one-sided limits: ``` Enjoy! -> lim[x->0+] 1/x Enjoy! -> ``` Hmmm...no output. Okay. Does any output work? ``` Enjoy! -> 3+2 5 Enjoy! -> ``` Okay, good, we at least have that much... Hmmm... ``` Enjoy! -> lim[x->0^+] 1/x Enjoy! -> ``` Nope, that's not it, either. Poking at the source code, [it doesn't seem as though one-sided limits are implemented](https://github.com/gogotanaka/Hilbert/blob/1750822d0577e69ab3784d635402cf87474e6f9f/lib/hilbert/lexer/main_lexer.rb#L25 https://github.com/gogotanaka/Hilbert/blob/1750822d0577e69ab... ). Well, okay, how about a simpler limit? ``` Enjoy! -> lim[x->0] x+2 Enjoy! -> ``` Uhhh...okay, how about some differentiation? ``` Enjoy! -> d/dx(cos(x)) I'm so sorry, something wrong. Please feel free to report this. Enjoy! -> ``` This error message is of no use, and I have no idea what's going on, but this language appears to be broken.