eul(er) Bc 5 letters is too much todo vectors vector operations (*,x,+,-) variable assignemnt/definition function assignment/definition riemann integrator dynamic integrator iterated riemann integrator for functions on Rn resources https://github.com/PhilippeSigaud/Pegged/wiki/PEG-Basics#an-example-grammar https://godoc.org/github.com/mna/pigeon