Support for <?python ?> processing instruction

[cmlenz]

Genshi should support the <?python ?> processing instruction as it is offered by Kid:

 http://kid-templating.org/language.html#embedding-code-blocks-python

[cmlenz]

First draft of the implementation

[cmlenz]

I've attached a patch that enables basic support for this feature.

Known issues:

• A lot of Python statements won't work yet, as the ASTTransformer hasn't been updated to support them yet
• The PI do not work in Python 2.3, as that version does not support providing a custom mapping object to exec and eval().
• The indentation of code blocks in processing instructions isn't currently normalized, so lines have to start at column 0 for multi-line suites.

[cmlenz]

Updated patch, supports more Python statements

[cmlenz]

Updated patch, candidate for merge

[cmlenz]

Another day, another patch.

This should fix all the issues noted above AFAICT, with one exception: the global statement does not work, nor am I sure how it could be made to work right now.

Anyway, I think this is ready for being merged into trunk. Testing/feedback would be highly appreciated!

[cboos]

Testing r467 + attachment:python_pi.3.diff , while viewing a custom query:

NameError: name '$append0' is not defined

File "C:\Workspace\src\trac\trunk\trac\web\main.py", line 394, in dispatch_request
  dispatcher.dispatch(req)
File "C:\Workspace\src\trac\trunk\trac\web\main.py", line 226, in dispatch
  content_type)
File "C:\Workspace\src\trac\trunk\trac\web\chrome.py", line 540, in render_template
  return stream.render(method, doctype=doctype)
File "c:\workspace\src\trac\genshi\trunk\genshi\core.py", line 146, in render
  output = u''.join(list(generator))
File "c:\workspace\src\trac\genshi\trunk\genshi\output.py", line 202, in __call__
  for kind, data, pos in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\output.py", line 488, in __call__
  for kind, data, pos in chain(stream, [(None, None, None)]):
File "c:\workspace\src\trac\genshi\trunk\genshi\output.py", line 438, in __call__
  for kind, data, pos in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\core.py", line 207, in _ensure
  for event in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\core.py", line 207, in _ensure
  for event in stream:
File "C:\Workspace\src\trac\trunk\trac\web\chrome.py", line 560, in _strip_accesskeys
  for kind, data, pos in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\core.py", line 207, in _ensure
  for event in stream:
File "C:\Workspace\src\trac\trunk\trac\web\chrome.py", line 549, in _generate
  for kind, data, pos in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\template\markup.py", line 236, in _include
  for event in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\template\markup.py", line 306, in _match
  content = list(self._include(content, ctxt))
File "c:\workspace\src\trac\genshi\trunk\genshi\template\markup.py", line 236, in _include
  for event in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\template\markup.py", line 281, in _match
  for event in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\template\markup.py", line 270, in _strip
  event = stream.next()
File "c:\workspace\src\trac\genshi\trunk\genshi\template\markup.py", line 226, in _exec
  for event in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\template\core.py", line 332, in _eval
  ctxt):
File "c:\workspace\src\trac\genshi\trunk\genshi\template\core.py", line 342, in _eval
  result = data.evaluate(ctxt)
File "c:\workspace\src\trac\genshi\trunk\genshi\template\eval.py", line 128, in evaluate
  '_lookup_item': _lookup_item}, _locals(data))
File "C:\Workspace\src\trac\trunk\templates\query.html", line 77, in <Expression u"any([(value == option) == (constraint.mode == "")                                               for value in constraint["values"]]) and "checked" or None">
  <input type="checkbox" id="${field_name}_$option" name="${field_name}"

(works fine with r467)

[cboos]

Same "NameError: name '$append0' is not defined" error for View Tickets, i.e. /report

...
File "c:\workspace\src\trac\genshi\trunk\genshi\template\core.py", line 363, in _flatten
  for event in stream:
File "c:\workspace\src\trac\genshi\trunk\genshi\template\directives.py", line 666, in __call__
  value = expr.evaluate(ctxt)
File "c:\workspace\src\trac\genshi\trunk\genshi\template\eval.py", line 128, in evaluate
  '_lookup_item': _lookup_item}, _locals(data))
File "report_view.html", line 39, in <Expression "?">

What's the meaning of "?" in Expression again?

[karlb@…]

Seems to work great. Some things become much easier or clearer with this PI. Thanks!

[cmlenz]

Updated patch

[cboos]

attachment:python_pi.5.diff seems to work just fine with Trac (couldn't reproduce the issues I had in comment:3 and 4.

[cmlenz]

Latest patch, slightly modified, applied in [497].