Evaluation of individual descriptors
For each individual descriptor in the macro description, the macro runtime evaluates the descriptor and arrives at a boolean result of true or false.
For example, if the descriptor is a String descriptor, then the macro runtime looks in the application screen at the row and column that the descriptor specifies, and compares the string at that location with the string that the descriptor specifies. If the two strings match, then the macro runtime assigns a value of true to the String descriptor. If the two strings do not match then the macro assigns a value of false to the String descriptor.
Usually a macro screen contains more than one descriptor.
However, if a macro screen contains only one descriptor (and assuming that the descriptor does not have the Inverse Descriptor option set to true) then if the single descriptor is true the entire description is true, and the macro runtime recognizes the macro screen as a match for the application screen. In contrast, if the single descriptor is false, then the entire description is false, and the macro screen is not recognized.