lxml package, for all its virtues, does complicate
life in one way for programs that generate mixed content, that is, XML content that is a
mixture of child elements and ordinary text.
Element instance has a
.text attribute that contains any text that
occurs before any child elements, and a
.tail attribute that contains any text that occurs after the closing tag of that element.
This function takes care of adding text content to the
inside of a given
parent has no child elements,
the new text is added to
appending it to the old value if there is any. However, if
parent does have child elements, the new
text is added to the
.tail attribute of the
last child element.
# - - - a d d T e x t M i x e d def addTextMixed ( parent, s ): """Add text s inside a parent element. [ (parent is an et.Element instance) and (s is a string) -> if parent has no element children -> parent.text +:= s else -> (last element child of parent).tail +:= s ] """
Regardless of where we are putting the text
s, we have to be sure not to overwrite any existing value
there. We use the Python “
or” operator to produce either the old value, or an
empty string, to which
s is appended before
storing it. Note also that the
len() of an
et.Element is the number of element
#-- 1 -- if len(parent) == 0: #-- 1.1 -- # [ if bool(parent.text) -> # parent.text +:= s # else -> # parent.text := s ] parent.text = (parent.text or "") + s else: #-- 1.2 -- # [ let # youngest == (last element child of parent) # in # if bool(youngest.tail) -> # youngest.tail +:= s # else -> # youngest.tail := s ] youngest = parent[-1] youngest.tail = (youngest.tail or "") + s