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Converting an instance of this class back to XML is one
situation where the quirky structure of the lxml package makes us work a little harder. The instance's ._phraseList attribute is the input to this process;
the output is a new para element attached to
the given parent, possibly with child elements such as genus or cite.
However, because of the way lxml places text
into either .text or .tail
attributes, we must translate the ._phraseList
in this way:
All initial phrases with no markup are concatenated to form
the .text of the new para
element.
For each element of the phrase list of the form (, where markup, t)markupNone,
create a new child element under the para
element, whose tag is markup.text is t
Any following markup-free phrases are concatenated and
stored in the .tail of the new child
element.
Here's an example. The input text looks like this:
<para>
Read about <genus>Tyrannus couchii</genus> in
<cite>NMOS Journal</cite> next month.
</para>
In the XML representation, the para node has
.text='\n Read about' and .tail=None. It has two children. The genus child has .text='Tyrannus couchi' and .tail=' in\n '. The cite
child has .text='NMOS Journal' and .tail=' next month.\n'.
The corresponding ._phraseList would be:
[(None, '\n Read about'),
('genus', 'Tyrannus couchi'),
(None, ' in\n '),
('cite', 'NMOS Journal'),
(None, ' next month.\n ')]
The first step is to create the new para
element and attach it to the parent.
# - - - P a r a g r a p h . w r i t e N o d e
def writeNode(self, parent):
"""Attach a new paragraph to the parent node.
"""
#-- 1 -
# [ parent := parent with a new rnc.PARA_N child added
# para := that child ]
para = et.SubElement(parent, rnc.PARA_N)
The logic that converts the __phraseList
back to XML is packaged in a separate function,
Section 19.5, “Paragraph.writeContent(): Write the
content of a paragraph”. This is
necessary in the special case that a Narrative instance contains only one Paragraph; in that case, the output is not
wrapped in a para element.
#-- 2 --
# [ para := para with XML content made from
# self._phraseList ]
self.writeContent(para)