* <grammar>:
<@statements>
<@definitions>
<block>
* <block>
<grammar>
* @statements contains:
<@control_statements>
<expression><?p6ws>?\;
* @definitions contains:
<rule_decl>
<sub_defin>
<_my>
* <expression>:
<expression> = <expression>
<term>
* <term>:
<variable>
<literal>
<ident>
* <variable>:
<varhash>
<vararray>
<varscalar>
<valueinhash>
<valueinhashref>