basic_record_ostream interface

[Dmitry Sokolov]

Hello!

I guess it could be useful to add own stream operators in basic_record_ostream. Template forward to base + manips, just to keep record_ostream reference through streaming sequence.
This would allow to write stream based direct log record modifiers, i.e. attribute assignment:

record_ostream& operator<<(record_ostream& os, const add_very_special_attribute& attr)
{
    log_record rec = os.get_record(); // add get_record_no_flush()?
    // add some very special attribute
    rec.attribute_values().insert(...);
    return os;
}
...
LOG << "AAA" << add_very_special_attribute(...);

Though... now it can be done with upcast from basic_formatting_ostream.

[Andrey Semashev]

You can use the add_value manipulator, although it should be in the beginning of the streaming expression.

[Dmitry Sokolov]

Anyway this doesn't lessen modification utility.
Apropos in case of add_value stream flush in get_record is also not obligatory.