How to use the mako.parsetree function in Mako

def match_python_block(self):
        match = self.match(r"<%(!)?")
        if match:
            line, pos = self.matched_lineno, self.matched_charpos
            text, end = self.parse_until_text(r'%>')
            # the trailing newline helps 
            # compiler.parse() not complain about indentation
            text = adjust_whitespace(text) + "\n" 
            self.append_node(
                            parsetree.Code, 
                            text, 
                            match.group(1)=='!', lineno=line, pos=pos)
            return True
        else:
            return False

def __init__(self, printer, compiler, node):
        self.printer = printer
        self.last_source_line = -1
        self.compiler = compiler
        self.node = node
        self.identifier_stack = [None]
 
        self.in_def = isinstance(node, (parsetree.DefTag, parsetree.BlockTag))

        if self.in_def:
            name = "render_%s" % node.funcname
            args = node.get_argument_expressions()
            filtered = len(node.filter_args.args) > 0 
            buffered = eval(node.attributes.get('buffered', 'False'))
            cached = eval(node.attributes.get('cached', 'False'))
            defs = None
            pagetag = None
            if node.is_block and not node.is_anonymous:
                args += ['**pageargs']
        else:
            defs = self.write_toplevel()
            pagetag = self.compiler.pagetag
            name = "render_body"
            if pagetag is not None:

def match_python_block(self):
        match = self.match(r"<%(!)?")
        if match:
            line, pos = self.matched_lineno, self.matched_charpos
            text, end = self.parse_until_text(False, r'%>')
            # the trailing newline helps
            # compiler.parse() not complain about indentation
            text = adjust_whitespace(text) + "\n"
            self.append_node(
                parsetree.Code,
                text,
                match.group(1) == '!', lineno=line, pos=pos)
            return True
        else:
            return False

def append_node(self, nodecls, *args, **kwargs):
        kwargs.setdefault('source', self.text)
        kwargs.setdefault('lineno', self.matched_lineno)
        kwargs.setdefault('pos', self.matched_charpos)
        kwargs['filename'] = self.filename
        node = nodecls(*args, **kwargs)
        if len(self.tag):
            self.tag[-1].nodes.append(node)
        else:
            self.template.nodes.append(node)
        # build a set of child nodes for the control line
        # (used for loop variable detection)
        if self.control_line:
            self.control_line[-1].nodes.append(node)
        if isinstance(node, parsetree.Tag):
            if len(self.tag):
                node.parent = self.tag[-1]
            self.tag.append(node)
        elif isinstance(node, parsetree.ControlLine):
            if node.isend:
                self.control_line.pop()
            elif node.is_primary:
                self.control_line.append(node)
            elif len(self.control_line) and \
                    not self.control_line[-1].is_ternary(node.keyword):
                raise exceptions.SyntaxException(
                          "Keyword '%s' not a legal ternary for keyword '%s'" %
                          (node.keyword, self.control_line[-1].keyword),
                          **self.exception_kwargs)

def __init__(self, text, filename=None, 
                        disable_unicode=False, 
                        input_encoding=None, preprocessor=None):
        self.text = text
        self.filename = filename
        self.template = parsetree.TemplateNode(self.filename)
        self.matched_lineno = 1
        self.matched_charpos = 0
        self.lineno = 1
        self.match_position = 0
        self.tag = []
        self.control_line = []
        self.disable_unicode = disable_unicode
        self.encoding = input_encoding
        
        if util.py3k and disable_unicode:
            raise exceptions.UnsupportedError(
                                    "Mako for Python 3 does not "
                                    "support disabling Unicode")
        
        if preprocessor is None:
            self.preprocessor = []

self.printer.writeline(None)
        else:
            self.write_source_comment(node)
            if self.compiler.enable_loop and node.keyword == 'for':
                text = mangle_mako_loop(node, self.printer)
            else:
                text = node.text
            self.printer.writeline(text)
            children = node.get_children()
            # this covers the three situations where we want to insert a pass:
            #    1) a ternary control line with no children,
            #    2) a primary control line with nothing but its own ternary
            #          and end control lines, and
            #    3) any control line with no content other than comments
            if not children or (
                    util.all(isinstance(c, (parsetree.Comment,
                                            parsetree.ControlLine))
                             for c in children) and
                    util.all((node.is_ternary(c.keyword) or c.isend)
                             for c in children
                             if isinstance(c, parsetree.ControlLine))):
                self.printer.writeline("pass")

def match_expression(self):
        match = self.match(r"\${")
        if match:
            line, pos = self.matched_lineno, self.matched_charpos
            text, end = self.parse_until_text(True, r'\|', r'}')
            if end == '|':
                escapes, end = self.parse_until_text(True, r'}')
            else:
                escapes = ""
            text = text.replace('\r\n', '\n')
            self.append_node(
                parsetree.Expression,
                text, escapes.strip(),
                lineno=line, pos=pos)
            return True
        else:
            return False

def match_comment(self):
        """matches the multiline version of a comment"""
        match = self.match(r"<%doc>(.*?)", re.S)
        if match:
            self.append_node(parsetree.Comment, match.group(1))
            return True
        else:
            return False