Notation Used

The following BNF-style convention is used:

1.

atom An atom is a single entry in a list. An atom cannot be expanded any further.

2.

Non-terminal A Non-terminal indicates a structure that is constructed by either one or more atoms, or of other non-terminals.

3.

[...] open-close angeled brackets denote the beginning and end of a list. For example, [this, is, a, list] is a list containing four atoms.

4.

* An asterisk denotes a list that may be repeated zero or more times. For example: [Repeat, this, list]* $\rightarrow$ [ ] (empty list) or [repeat, this, list],..., [repeat, this, list].

5.

+ A plus sign denotes a list that occurs one or more times. time.

6.

$\mid$ The ``$\mid$'' sign indicates a choice. For example: Person = man $\mid$ woman