metadescription> ::= declaration dimensions
declaration ::= define identifier ":"
dimensions ::= dimension {dimensions}
dimension ::= logtopo | evtimeline
logtopo ::= topology objects cardinality relationships
evtimeline ::= timeline definitions timeline invariants
objects ::= objects object {object}
object ::= alias | dobject
alias ::= obname "." obfield
dobject ::= obtype [obname] ":=" "{" obass "}"
obass ::= obass obass?
obass ::= obvar | obstate
obvar ::= obtype obname value?
obstate ::= state "=" value
obname ::= identifier
obtype from list of object types
value ::= number | string
identifier ::= letter { letter | digit }
letter diggit number string