BNF Notation for HEML

metadescription> ::= declaration dimensions

declaration ::= define identifier ":"

dimensions ::= dimension {dimensions}

dimension ::= logtopo | evtimeline

logtopo ::= topology objects cardinality relationships

evtimeline ::= timeline definitions timeline invariants

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