Feature Grammar rule formatting

Some general rule writing guidelines are:

The first line must specify the start symbol for the grammar (e.g. what the root node should be called).

Each rule should be on a separate line.
Lines that begin with # are comments and rules in these lines are not used by the grammar.
Blank lines are simply ignored.
Do not use plus signs as they have a special significance to the parser internals.
Each rule should have only one delimiter symbol (->).

Lexical rules

Here's an example lexical rule:

	A -> 'fuzzy'

Lexical rules should adhere to the following guidelines:

Lexical rules should use an arrow (->), like syntactic rules, to separate part of speech labels from words.
Words must be indicated using single quotes.
Multiple words can be specified for a single part of speech using a pipe symbol (|)
Features can be specified using a nested structure on the left hand side of the rule. Feature values must be enclosed in single quotes.

Both syntactic rules (->) to separate mothers from daughters.
Rules should be of the form
Mother -> Daughter1 Daughter2 Daughter3 ...
Notice that the daughters are separated by spaces.
If you specify terms on the right of the -> they all must be specified on the left hand side of one of your other rules.
There is currently no way to indicate repetition or optionality. This is a target for a future release
A pipe symbol (|) can be used to indicate a series of rules that all share a mother.
Features can be specified for both mother and daughters using a bracketing structure to the right of the symbol.

Features can also use variables. Variables consist of a question mark followed by a variable name. For example if you wanted to indicate that the person features should be shared between the mother and the daughters, you could do the following: