Question

I am new to context free grammar and i’ve only learned stuff like left/rightmost derivation and G=(V, E, R ,S) so far. But the problem I’m trying to solve involves java prototype and I’m not very good at java. So I don’t really know where to start.

Give a context-free grammar for the sub-language of Java prototypes.

int myMethod();
double myMethod(int x, double y);
static double f(int x, double y, int z);
public static double g();

These are methods and variables, how can I relate to things like S => Sa | e ? And what is the start symbol?

Thank you!

Answer 1

All java you need to know about method signatures is located on single doc page. You start writing grammar by identifying grammar variables. The obvious ones to start with are

- type
- argument_name
- method_name
- parenthesis (2 terminal symbols)
- comma (terminal)
- semicolon (terminal)

You introduce more variables while writing grammar rules, for example

argument_list : argument
              | argument, comma, argument_list

As soon as you finish your grammar you’d have the “top most rule”:

method_signature : ... 

The method_signature is the start symbol.