SymEngine is a standalone fast C++ symbolic manipulation library.
Optional thin wrappers allow usage of the library from other languages, e.g.:

* C wrappers allow usage from C, or as a basis for other wrappers (the
  symengine/cwrapper.h file)
* Python wrappers allow easy usage from Python and integration with SymPy and
  Sage (the symengine.py repository)
* Ruby wrappers (the symengine.rb repository)
* Julia wrappers (the SymEngine.jl repository)
* Haskell wrappers (the symengine.hs repository)