SymbolicNim, symbolic algebra in Nim

[cblake]

I think [Fricas](https://en.wikipedia.org/wiki/FriCAS) (a 
homonym-with-slightly-different emphasis for Free CAS = Free Computer Algebra 
System) has the most complete/carefully thought out "type system" for computer 
algebra/calculus/general math. It's based on IBM's 
[Axiom](https://en.wikipedia.org/wiki/Axiom_\(computer_algebra_system\)) which 
was open sourced (written in Common Lisp). Of the two, `fricas` seems the 
active community/actually "just works" when you install it. It's graphical 
interface is unquestionably archaic, but it's CA types and algorithms seem 
maybe the most solid of the open source options. I believe it is the only such 
system that guarantees if a symbolic indefinite integral has an answer in terms 
of elementary functions then it will be found.