This is a model of first order logic expressions, allowing you to manipulate them as objects instead of just strings. Prerequisites:Refactoring BrowserSmaCC Runtime PackageSmaCC Development Package For example, inspect the following lines to get the expression correspondingto "(p = q) = (not p or q)": | p q |p := LVariable named: 'p'.q := LVariable named: 'q'.p = q equiv: (p not | q). Now, the same formula could be created using:LExpression fromString: '{p=q = not p or q}' More complex formulas can also be created and evaluated, for example try:| exp |exp := LExpression fromString: '{V(x)[x even]}'.exp valueDomains: {'x' - #(2 4 6 8 10 12 )}. See more examples in the Homepage and on the Logic-Tests category. I hope you enjoy it!Dany