NOT.Preface:3.3 - Constituent actions in ongoing work

Defining an operator’s binding rule can be part of constructing an expression grammar while a notation for working calculations is being designed. If users must transform an expression without changing its meaning, visually convenient grouping is insufficient: the interpretation of the transformed expression must remain recoverable. Symbol recognition and subject knowledge can both be present while the intermediate ability to follow binding and transformation rules is absent. The notation design must provide those rules and support their use; a successful reading of one expression does not establish the whole notation’s suitability.

FPF B.1.5.EW helps recover these constituent–whole connections; B.1.5.RS examines a proposed replacement. Use the parts of the vertical that can change the present result. A Method described here can require additional capability, available support and compatible resources at other grains.