  << ^ N W - G E T   M A C R O   L E N G T H >>
 Sets the ALU Q register to the length of the macro indicated by the character
following ^NW (which must be there if in a macro). If Q becomes -1, calling the
indicated macro would cause an error. If Q becomes zero, the indicated macro
must have been a pseudo: calling it is allowed and it may return some
characters but the Q editor can't determine how many.
 To see the value of the Q register: FI ^<DMP> will show this as the last item;
and FI ^<PSHQ>^<POP 0>^ND^N^<7000> will output only the contents of Q.
