STRUCT
public struct MonkeyLexer: Lexer
public var readingChars: (current: Character?, next: Character?)?
public let filePath: URL?
public var input: String
public var streamReader: StreamReader?
public var currentLineNumber = 0
public var currentColumn = 0
public var readCharacterCount = 0
public var currentLine = ""
public init()
public init(withFilePath filePath: URL)
public init(withString input: String)
public mutating func readLine()
public mutating func nextToken() -> Token