Python jinja2.nodes 模块，Block() 实例源码

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hypens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result

def parse_block(self):
        node = nodes.Block(lineno=next(self.stream).lineno)
        node.name = self.stream.expect('name').value
        node.scoped = self.stream.skip_if('name:scoped')

        # common problem people encounter when switching from django
        # to jinja.  we do not support hyphens in block names, so let's
        # raise a nicer error message in that case.
        if self.stream.current.type == 'sub':
            self.fail('Block names in Jinja have to be valid Python '
                      'identifiers and may not contain hyphens, use an '
                      'underscore instead.')

        node.body = self.parse_statements(('name:endblock',), drop_needle=True)
        self.stream.skip_if('name:' + node.name)
        return node

def visit_If(self, node):
        """Eliminate dead code."""
        # do not optimize ifs that have a block inside so that it doesn't
        # break super().
        if node.find(nodes.Block) is not None:
            return self.generic_visit(node)
        try:
            val = self.visit(node.test).as_const()
        except nodes.Impossible:
            return self.generic_visit(node)
        if val:
            body = node.body
        else:
            body = node.else_
        result = []
        for node in body:
            result.extend(self.visit_list(node))
        return result