An AS file is tokenized to a sequence of IASToken objects,
using a tokenizer produced by a JFlex .lex file.
The tokens are then used to build an abstract syntax tree for the AS file
whose root is an IFileNode. This process is driven
by a parser produced from an ANTLR .g file.
An MXML file is tokenized to a sequence of IMXMLToken objects,
using a tokenizer produced by a JFlex .lex file.
The tokens are then used to build an syntactic representation
of the MXML file as tags and attributes (MXMLData).
An abstract syntax tree for the MXML file is built from the
MXMLData.