appypod-rattail/px/__init__.py

58 lines
2.4 KiB
Python

'''PX stands for *P*ython *X*ML. It is a templating engine that reuses the pod
engine to produce XML (including XHTML) from templates written as a mix of
Python and XML.'''
# ------------------------------------------------------------------------------
from UserDict import UserDict
from px_parser import PxParser, PxEnvironment
from appy.pod.renderer import BAD_CONTEXT
# Exception class --------------------------------------------------------------
class PxError(Exception): pass
# ------------------------------------------------------------------------------
class Px:
'''Represents a (chunk of) PX code.'''
def __init__(self, content, isFileName=False, partial=True):
'''p_content is the PX code, as a string, or a file name if p_isFileName
is True. If this code represents a complete XML file, p_partial is
False. Else, we must surround p_content with a root tag to be able
to parse it with a SAX parser.'''
# Get the PX content
if isFileName:
f = file(content)
self.content = f.read()
f.close()
else:
self.content = content
# It this content a complete XML file, or just some part of it?
if partial:
# Surround the partial chunk with a root tag: it must be valid XML.
self.content = '<x>%s</x>' % self.content
self.partial = partial
# Create a PX parser
self.parser = PxParser(PxEnvironment(), self)
# Parses self.content (a PX code in a string) with self.parser, to
# produce a tree of memory buffers.
self.parser.parse(self.content)
def __call__(self, context):
# Get the context in a standardized form.
evalContext = {}
if hasattr(context, '__dict__'):
evalContext.update(context.__dict__)
elif isinstance(context, dict) or isinstance(context, UserDict):
evalContext.update(context)
else:
raise PxError(BAD_CONTEXT)
# Store the context on the PX environment
self.parser.env.context = evalContext
# Render the PX result and return it
env = self.parser.env
env.ast.evaluate()
res = env.result.content
# Clean the res, for the next evaluation
env.result.clean()
return res
# ------------------------------------------------------------------------------