Institute of Information Science - University of Miskolc

Syntactic rules can also be modeled using graphs, for example in the following way:

The idea is to represent all possibilities of the BNF formula in some graphical way.

Even if someone is unfamiliar with the PASCAL language, they would be able to declare syntactically correct variables using the graph:

var age, weekdays : integer;
var taxrate, netIncome : real;
var choice, isready : boolean;
  initials, grade : char;
  name, surname : string;

This shows how graphical representations can help understand and construct syntactically correct structures in programming languages.