3.1 A GRAMMAR for dates. A GRAMMAR consists in 1) the PS-RULES, describing how the calendar is constituted, 2) SS-RULES, describing how the date name pieces are classified, and 3) the LEXICON. It may help in the understanding of the rules to get an idea of what the symbols in these rules stand for. The list has the symbols first with the English interpretation in a second column. The initial symbol is DNP. It is found on the left hand side of the first rule(s). It is a non-terminal symbol. This kind of symbol is one that is found on the left side of one or more rules, but also on the right side of one or more rule(s). Terminal symbols are found only on the right side of one or more rules. The rule
DNP (EN) (APP) (DOY) YN
is read and interpreted as follows: A date name phrase consists of any combination of era names, approximative, and/or the day of year, all of which is followed by the year name. The parentheses are a way of combining two rules disjunctively. A disjunctive combination without common elements uses curly brackets. The first device reduces into one rule eight different rules written with it. The cursory sketch of the grammatical rules in ¶3.4 is augmented by entries for the various elements in the glossary. The reader may click on the symbols in the figure to see the definition, or look it up in the glossary directly. It is there that hopefully the analysis will be explained that motivated this particular arrangement of the elements in the linguistic structures described.