2.8.4 Command Expressions

A command expression is any expression that is decorated with a command button. When touched, the command button causes a transformation to be applied to the expression. When simplified, a command expression behaves as if the command button had been touched.

A command expression is entered as a postfix operator using the notation !command. It is displayed as a button under its operand, like this: (1+2) !simplify. When the button is touched or when Simplify is applied, the action is applied.