class ParserError(Exception):
    """Base exception for parser errors"""
    pass

class UnsupportedFormatError(ParserError):
    """Raised when document format is not supported"""
    pass

class ParseError(ParserError):
    """Raised when document parsing fails"""
    pass

class ValidationError(ParserError):
    """Raised when document validation fails"""
    pass

class EncodingError(ParserError):
    """Raised when document encoding cannot be determined or is not supported"""
    pass