Stack manipulation

[flying-sheep]

For my reStructuredText project, I’d like to generalize a syntax construct called directive

.. directive-name:: argument

   indented
   block

Both arguments and blocks are either reStructuredText or something else, depending on the directive. E.g. in the following case both argument and the block are plain text (dedent the block and done):

.. code:: python

   def foo(): pass

This directive on the other hand has no arguments and a rST-formatted block:

.. note::

   I have *italic* text

   .. code::

      And nested syntax

My question:

I store the indentation in the stack. Do I have to copy and trim the text to be able to parse it, or is there a way to modify a parser’s stack before letting it do its thing?