I have looked at the following software tools:
ANTLR seems the most straight-forward, however its documentation is lacking. Ragel looks possible, too, but I do not see an easy way to convert BNF into its syntax.
What other tools are available that can take BNF input and generate a corresponding, Unicode-friendly, cross-platform, standalone, C++ parser?
Many thanks for all suggestions.
Edit: Changed Objective-C requirement to C++.