libstring-bufferstack-perl 1.13-1 (i386 binary) in ubuntu lucid

 String::BufferStack provides some functions to store data into
 nested buffers
 .
 By default, all of the buffers flow directly to the output method,
 but individual levels of the stack can apply filters, or store their
 output in a scalar reference
 .
 The main consumers of this module are templating systems, like
 Template::Declare, which needs to manipulate nested buffes.