Rust Lexer for pygments

gistfile1.py

class RustLexer(RegexLexer):
    """
    Lexer for Mozilla's Rust programming language
    """
    name = 'Rust'
    filenames = ['*.rs', '*.rc']
    aliases = ['rust']
    mimetypes = ['text/x-rustsrc']

    tokens = {
        'root': [
            # Whitespace and Comments
            (r'\n', Text),
            (r'\s+', Text),
            (r'//(.*?)\n', Comment.Single),
            (r'/[*](.|\n)*?[*]/', Comment.Multiline),

            # Keywords
            (r'(alt|as|assert|be|break|check|claim|class|const'
             r'|cont|copy|crust|do|else|enum|export|fail'
             r'|false|fn|for|if|iface|impl|import|let|log'
             r'|loop|mod|mut|native|pure|resource|ret|true'
             r'|type|unsafe|use|white|note|bind|prove|unchecked'
             r'|with|syntax)\b', Keyword),

            # Character Literal
            (r"""'(\\['"\\nrt]|\\x[0-9a-fA-F]{2}|\\[0-7]{1,3}"""
             r"""|\\u[0-9a-fA-F]{4}|\\U[0-9a-fA-F]{8}|.)'""",
             String.Char),
            # Binary Literal
            (r'0[Bb][01_]+', Number, 'number_lit'),
            # Octal Literal
            (r'0[0-7_]+', Number.Oct, 'number_lit'),
            # Hexadecimal Literal
            (r'0[xX][0-9a-fA-F_]+', Number.Hex, 'number_lit'),
            # Decimal Literal
            (r'[0-9][0-9_]*(\.[0-9_]+[eE][+\-]?'
             r'[0-9_]+|\.[0-9_]*|[eE][+\-]?[0-9_]+)?', Number, 'number_lit'),
            # String Literal
            (r'"', String, 'string'),

            # Operators and Punctuation
            (r'[{}()\[\],.;]', Punctuation),
            (r'[+\-*/%&|<>^!~@=:?]', Operator),

            # Identifier
            (r'[a-zA-Z_$][a-zA-Z0-9_]*', Name),

			# Attributes
            (r'#\[', Comment.Preproc, 'attribute['),
            (r'#\(', Comment.Preproc, 'attribute('),
            # Macros
            (r'#[A-Za-z_][A-Za-z0-9_]*\[', Comment.Preproc, 'attribute['),
            (r'#[A-Za-z_][A-Za-z0-9_]*\(', Comment.Preproc, 'attribute(')
        ],
        'number_lit': {
            (r'(([ui](8|16|32|64)?)|(f(32|64)?))?', Keyword, '#pop')
        },
        'string': {
            (r'"', String, '#pop'),
            (r"""\\['"\\nrt]|\\x[0-9a-fA-F]{2}|\\[0-7]{1,3}"""
             r"""|\\u[0-9a-fA-F]{4}|\\U[0-9a-fA-F]{8}""", String.Escape),
            (r'[^\\"]+', String),
            (r'\\', String)
        },
        'attribute_common': {
            (r'"', String, 'string'),
            (r'\[', Comment.Preproc, 'attribute['),
            (r'\(', Comment.Preproc, 'attribute('),
        },
        'attribute[': {
            include('attribute_common'),
            (r'\];?', Comment.Preproc, '#pop'),
            (r'[^"\]]+', Comment.Preproc)
        },
        'attribute(': {
            include('attribute_common'),
            (r'\);?', Comment.Preproc, '#pop'),
            (r'[^"\)]+', Comment.Preproc)
        }
    }