::= "\begin{tikzpicture}" ? * "\end{tikzpicture}" ::= | | | ::= "\begin{pgfonlayer}" DELIMITED_STRING | "\end{pgfonlayer}" ::= "[" ("," )* "]" ::= * "=" | * ::= WORD | number ::= * | QUOTED_STRING ::= "\node" ? "at" DELIMITED_STRING ";" ::= "(" (NATURAL_NUMBER | WORD) (".center")? ")" ::= "(" NUMBER "," NUMBER ")" ::= "\draw" ? "to" ? ( | "()") ";" ::= "node" ? DELIMITED_STRING ::= "\path" "[use as bounding box]" "rectangle" ";"