This object contains implicit conversions that come in handy when using the ^^' combinator
{@see Parsers} to construct an AST from the concrete syntax.
The reason for this is that the sequential composition combinator (~') combines its constituents
into a ~.
PackratParsers is a component that extends the parser combinators
provided by Parsers with a memoization facility
(Packrat Parsing).
Parsers is a component that provides generic
parser combinators.