Boost C++ Libraries: Ticket #2613: Default arguments break word-wrapping.

attachment set

anonymous — Wed, 24 Dec 2008 14:28:11 GMT

attachment → test.cpp

Run to see the broken help output.

Vladimir Prus — Wed, 24 Dec 2008 16:28:31 GMT

Please specify how the produced output differs from expected output, and why you expect the output you expect.

Peter Simons — Wed, 24 Dec 2008 17:12:08 GMT

With Boost 1.37.0, the attached program generates the following output:

$ g++ test.cpp -lboost_program_options && ./a.out
| Supported options:
|   --help                          this is a sufficiently long text to requ
|                                   ire word-wrapping

Look closely at the description of the "--help" option. You'll find that word-wrapping is performed in the middle of the word, i.e. "require" is broken apart as "requ-ire". This is contrary to what I expect because of the rules of syllabication, which you'll find described at http://en.wikipedia.org/wiki/Syllabification. Now, those rules are somewhat complex and might be considered beyond the scope of a command-line argument parsing library. Thus, most code that needs to perform word-wrapping opts to use a simpler approximation, i.e. to break lines apart at *whitespace*. If you check out your source code, "options_description.cpp", you'll find that you have implemented an algorithm that does this, but unfortunately it appears that your code fails to take the length of the default argument into account. I say this because the algorithm works just fine when there's no default argument. When there is one, word-wrapping does not work fine.

If you need further clarification, please don't hesitate to ask.

attachment set

s.ochsenknecht@… — Mon, 09 Nov 2009 14:43:29 GMT

attachment → patch_ticket2613.diff

patch

s.ochsenknecht@… — Mon, 09 Nov 2009 14:44:49 GMT

I just attached a patch which improves the word wrapping (small fix). I also added a test case for word wrapping.

Please comment.

cc changed

s.ochsenknecht@… — Mon, 09 Nov 2009 15:28:25 GMT

cc s.ochsenknecht@… added

milestone changed

Peter Simons — Mon, 09 Nov 2009 16:07:41 GMT

milestone Boost 1.38.0 → Boost 1.41.0

The patch applies cleanly to the current SVN HEAD, and it does fix the problem in my test program. Looks good to me. Thank you very much.

status changed; resolution set

Vladimir Prus — Mon, 09 Nov 2009 16:12:33 GMT

status new → closed
resolution → fixed

(In [57517]) Fix wordwrapping in presense of default parameters.

Fixes #2613. Patch from Sascha Ochsenknecht.

milestone changed

Sascha Ochsenknecht — Sun, 06 Dec 2009 12:20:30 GMT

milestone Boost 1.41.0 → Boost 1.42.0