Item API needs operator<<

[Paul J. Lucas]

To emit the string value of an Item to an ostream, you currently have to use getStringValue() or getStringValue2(). This is inefficient since a string that is otherwise not needed needs to be created.

Instead, there should be a global operator<< defined:

    std::ostream& operator<<( std::ostream&, store::Item const& );

Its implementation could simply call a new protected, pure virtual member function for Item:

    virtual void emit( std::ostream& ) const = 0;

[Matthias Brantner (matthias-brantner)]

I like the suggestion. However, the function should probably be called emitStringValue in order to make it clear what the exact semantics is.