RubyChem (pronounced /ˈruːˈbeːˈkːˈem/) is a freely available (MIT License) program, written in Ruby, supporting the calculation of moles, balancing chemical equations and valence orbital calculations.
Example
The Ruby official distribution also includes "irb" (Interactive Ruby Shell), an interactive command-line interpreter which can be used to test code quickly. The following code fragment represents a sample session using irb: