Yes, it deals with everything involved in "parsing" which covers all aspects of starting from a text document and converting it into a tree structure that can b

Yes, it deals with everything involved in "parsing" which covers all aspects of starting from a text document and converting it into a tree structure that can be used either for code generation or for manipulating the code. Lexing isn't all that different than parsing anyway. Both involve the recognition of "tokens" based on a stream of data. In the case of a lexer, the "tokens" are usually the characters taken character by character. For parsing, the "tokens" are identifiers, values, operators, etc.