SD06 - Grammars 2

Question 1

What does the ‘*’ symbol mean in a grammar definition?

Answer 1

‘’ signifies an element that can be repeated zero or more times. e.g.
A -> 0B can produce:
0,0B,0BB,0BBB etc.

Question 2

What symbol is used for an element which can be used one or more times?

Answer 2

The ‘+’ symbol indicates an element that can be repeated one or more times
A -> 0B+ can produce:
0B,0BB,0BBB etc.

Question 3

What is meant by a non-deterministic grammar?

Answer 3

There is more than one valid choice at certain parts

Some expressions can have several possible parse trees