matches \w (alphanumerics and underscore) is removed.

    """

    # Transform all whitespace to underscore

    idstring = re.sub(r'\s', "_", idstring)

    # Remove everything that is not a hyphen or a member of \w

    idstring = re.sub(r'(?!-)\W', "", idstring).lower()

    return idstring

def as_html(parsed_lines, table_class='code-difftable', line_class='line',

            old_lineno_class='lineno old', new_lineno_class='lineno new',

            no_lineno_class='lineno',

            code_class='code'):

    """

    Return given diff as html table with customized css classes

    """

    _html_empty = True

    _html = []

    _html.append('''<table class="%(table_class)s">\n''' % {

        'table_class': table_class

    })

    for file_info in parsed_lines:

        for chunk in file_info['chunks']:

            _html_empty = False

            for change in chunk:

                _html.append('''<tr class="%(lc)s %(action)s">\n''' % {

                    'lc': line_class,

                    'action': change['action']

                })

                if change['old_lineno'] or change['new_lineno']:

                    ###########################################################

                    # OLD LINE NUMBER

                    ###########################################################

                    anchor_old = "%(filename)s_o%(oldline_no)s" % {

                        'filename': _safe_id(file_info['filename']),

                        'oldline_no': change['old_lineno']

                    }

                    anchor_old_id = ''

                    if change['old_lineno']:

                        anchor_old_id = 'id="%s"' % anchor_old

                    _html.append('''\t<td %(a_id)s class="%(olc)s">''' % {

                        'a_id': anchor_old_id,

                        'olc': old_lineno_class,

                    })

                    _html.append('''<a href="%(url)s" data-pseudo-content="%(label)s"></a>''' % {

                        'label': change['old_lineno'],

                    _html.append('''</td>\n''')

                    ###########################################################

                    # NEW LINE NUMBER

                    ###########################################################

                    anchor_new = "%(filename)s_n%(newline_no)s" % {

                        'filename': _safe_id(file_info['filename']),

                        'newline_no': change['new_lineno']

                    }

                    anchor_new_id = ''

                    if change['new_lineno']:

                        anchor_new_id = 'id="%s"' % anchor_new

                    _html.append('''\t<td %(a_id)s class="%(nlc)s">''' % {

                        'a_id': anchor_new_id,

                        'nlc': new_lineno_class

                    })

                    _html.append('''<a href="%(url)s" data-pseudo-content="%(label)s"></a>''' % {

                        'label': change['new_lineno'],

                        'url': '#%s' % anchor_new,

                    })

                    _html.append('''</td>\n''')

                else:

                    ###########################################################

                    # NO LINE NUMBER

                    ###########################################################

                        'filename': _safe_id(file_info['filename']),

                    }

                    _html.append('''\t<td id="%(anchor)s" class="%(olc)s" colspan="2">''' % {

                        'anchor': anchor,

                        'olc': no_lineno_class,

                    })

                    _html.append('''</td>\n''')

                ###########################################################

                # CODE

                ###########################################################

                _html.append('''\t<td class="%(cc)s">''' % {

                    'cc': code_class,

                })

                _html.append('''\n\t\t<div class="add-bubble"><div>&nbsp;</div></div><pre>%(code)s</pre>\n''' % {

                    'code': change['line']

                })

                _html.append('''\t</td>''')

                _html.append('''\n</tr>\n''')

    _html.append('''</table>''')

    if _html_empty:

        return None

    return ''.join(_html)

def wrap_to_table(html):

                # Git binary patch

                if head['bin_patch']:

                    stats['ops'][BIN_FILENODE] = 'binary diff not shown'

                chunks = []

            if op == 'removed' and chunks:

                # a way of seeing deleted content could perhaps be nice - but

                # not with the current UI

                chunks = []

            # show helpful additional texts for mode change and renaming, but not for plain 'modified file'

            msgs = [

                {

                    'old_lineno': '',

                    'new_lineno': '',

                    'action': 'context',

                    'line': msg,

                }

                for op_, msg in stats['ops'].items()

                if op_ != MOD_FILENODE

            ]

            if msgs:

                chunks.insert(0, msgs)

            _files.append({

                'old_filename':     head['a_path'],

                'filename':         head['b_path'],

                'old_revision':     head['a_blob_id'],

                'new_revision':     head['b_blob_id'],

                'chunks':           chunks,

                'operation':        op,

                'stats':            stats,

            })

        if not html:

            return _files

        for diff_data in _files:

            for chunk in diff_data['chunks']:

                for change in chunk:

                    change['line'] = _escaper(change['line'])

                # highlight inline changes when one del is followed by one add

                lineiter = iter(chunk)

                try:

                    peekline = next(lineiter)

                    while True:

                        # find a first del line

                        while peekline['action'] != 'del':