Suggest class names if class name not found

[gf712]

I found that it can be a bit annoying finding the correct spelling of a class name using factories. This PR adds an exception that suggests alternatives when using the Python API.

Example:

In [1]: import shogun as sg

In [2]: sg.kernel("GaussianKernels", log_width=1)
---------------------------------------------------------------------------
SystemError                               Traceback (most recent call last)
~/shogun/build/src/interfaces/python/shogun.py in wrapper(*args, **kwargs)
    151         try:
--> 152             return func(*args, **kwargs)
    153         except SystemError as e:

~/shogun/build/src/interfaces/python/shogun.py in _internal_factory(name, **kwargs)
    174     def _internal_factory(name, **kwargs):
--> 175         new_obj = _obj(name)
    176         for k,v in kwargs.items():

SystemError: [ERROR] In file /home/gil/shogun/src/shogun/base/class_list.h line 51: Class GaussianKernels with primitive type SGOBJECT does not exist.


During handling of the above exception, another exception occurred:

SystemError                               Traceback (most recent call last)
<ipython-input-2-dd78094495dc> in <module>()
----> 1 sg.kernel("GaussianKernels", log_width=1)

~/shogun/build/src/interfaces/python/shogun.py in wrapper(*args, **kwargs)
    160             dists = [_internal_iterative_levenshtein(wrong_class_name, x) for x in all_objects]
    161             did_you_mean_class_name = all_objects[dists.index(min(dists))]
--> 162             raise SystemError("{} Did you mean {}?".format(match.group(), did_you_mean_class_name))
    163     return wrapper
    164 

SystemError: Class GaussianKernels with primitive type SGOBJECT does not exist. Did you mean GaussianKernel?

This increases the size of the SWIG source file, but in the long term could implement something like this in C++, and then have it available in all languages? Just need to implement Levenshtein in C++.

[karlnapf]

I like this, but indeed it should work for all langs rather than just Python or?

[gf712]

yup, someone just has to write the Levenshtein algo :D

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[gf712]

closing this because it is only PoC, but should be implemented one day