Using the standard inspect module instead of accessing __doc__ directly allows
the tests to pass both when using and not using -builtin, as whitespace-only
differences between the docstrings don't matter then because inspect.getdoc()
removes the indentation and the leading and trailing spaces.
This is similar to what had been already done for python_docstring unit test
in fa282b3540.
This is unnecessary and inconsistent with "builtin" case in which the
docstrings are not indented in the generated C++ code, thus making it
impossible to write tests working in both cases.
Most of the changes in this commit simply remove the extra whitespace from the
expected values in the tests.
In addition to translating the comment itself, also document the type of the
object returned. This is consistent with generating not only :param: but also
:type: for the parameters documented using @param.
The most important change is to ensure that the "Overload" headers added by
PyDocConverter code are indented correctly, i.e. using the same indent level
as the comment itself, otherwise Sphinx directives such as :param: were not
parsed correctly.
Also add a vertical separator using reST "|" formatting character to increase
separation between the overloads.
Make the rules for combining explicitly specified docstring, autodoc one and
the one obtained by translating Doxygen comments implicit in the structure of
the code itself instead of writing complicated conditions checking them.
This results in small changes to the whitespace in the generated Python code
when using autodoc, but this makes it PEP 8-compliant, so it is the right
thing to do anyhow.
Also cache the docstring built from translated Doxygen comments. The existing
code seemed to intend to do it, but didn't, really. This helps with
performance generally speaking (-10% for a relatively big library using a lot
of Doxygen comments) and also makes debugging Doxygen translation code less
painful as it's executed only once instead of twice for each comment.
Finally, avoid putting "r", used for Python raw strings, into docstrings in C
code, it is really not needed there.
It is very useful to be able to click on the parameter types in a function
documentation to go to this parameter description, so always use hyperlink
markup for the parameters of class types, even if not all of them are
necessarily documented -- Sphinx doesn't seem to complain about links to
unknown classes.
For the parameter documentation to be really taken as such, in its entirety,
by Sphinx, it must be indented relative to the :param: tag. Do this by
appending an extra indent after every line of the output and work around the
unnecessary indent of the last line by removing the trailing whitespace.
This required updating the existing tests and removing the expected but not
present any more whitespace from them, but as trailing whitespace in the
documentation is at best insignificant (and at worst harmful) anyhow, this is
not a big price to pay for simpler translator code.
Sphinx doesn't allow sections inside the function documentation and gives tons
of SEVERE warnings for them, so while just emphasizing the "Overload" header
is not ideal, it is better than before because at least the string "Overload"
itself appears in the Sphinx-generated output.
Using C++ types in documentation for Python users is more harmful than
useless, so use Python types whenever possible and allow defining "doctype"
typemap to customize this for the user-defined types.
reST is standard Python markup, so use *...*, ``...`` and so on instead of
_..._, '...' etc.
No other changes even though the mapping of some Doxygen tags to markup used
for them seems suspicions (e.g. \var almost certainly should be the same as
\em).
Use the more or less standard :param:, :type:, :return: and :raises: in the
function/methods descriptions.
Update the output expected from the Python tests accordingly.
Update Doxygen-specific Python unit tests to work with the new indentation.
Update one of Doxygen-specific Java tests to still build with the new handling
of srcdir.
