Limiting, comparing LJ/Mie/Exp6, electrostatic, bond, angle, dihedral, and improper expressions?

[bc118]

I may have missed this if it already exists.

Do we need to limit the equations/variable name or do we have a good method of comparing the LJ/Mie/Exp6, electrostatic, bond, angle, dihedral, and improper expressions between different FF/xml files?

For example:

• limit the variable name to ep and/or epsilon only and not accept eplis ... as a variable name?
• Do we want to build functions for comparing in gmso, as many writers may use them, or do we want every engine to do their own way?
• Other fancy/better ways to do this?