config's automatic conversion of an attribute to bool gives unexpected behavior

[Pentarctagon]

When using the automatic conversion of a config attribute to a bool, such as with:

bool b = cfg["some_attribute"]

The variable b will always be false regardless of the attribute's actual value. This is due to calling operator int() in config_attribute_value.hpp instead of explicit operator bool(), which results in using the attribute_numeric_visitor which uses the default value of 0 for bool values instead of its actual value.

Potential solutions mentioned by celticminstrel from IRC:

• Remove the explicit annotation on operator bool().
• Remove operator bool() entirely, and also remove operator int().
• Remove operator bool() and replace operator int() with a custom function using a different visitor that returns 0 or 1 if the value is a bool.

Any fix for this issue should also include test cases added to the boost unit tests for this behavior as well.

[gfgtdf]

instead of removing both operators we could probably also make the operator int explicit too,