An object representing a grammar symbol created by Farkle.Builder. It corresponds to either a standalone terminal or a nonterminal that contains other designtime Farkles.
Designtime Farkles cannot be used to parse text but can be
composed into larger designtime Farkles. To actually use them, they
have to be converted to a RuntimeFarkle{T} which however
is not composable. This one-way conversion is performed by the RuntimeFarkle.build
function or the Build extension method.
This interface has no members on its own; they are inherited from DesigntimeFarkle.
User code must not implement this interface, or an exception might be thrown.