Modify expression builder to allow "."

[EncomLab]

I love this version of TinyBasic and use it often with my students. How can the expression builder be modified to accept decimal numbers? Allowing for this would vastly expand the usability of the program as it's simple to include floating point functions once the expression builder allows for those numbers to be entered. Hard coding FP numbers causes no issues, i.e hard coding Pi then calling it in a allows the basic geometry command has the correct output of an equation.