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#        Character Attributes				   #
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1. Types of attributes

Currently supported attributes are underline, inverse (you
may call it highlight or standout), and bold.  Termcap
entries used for there attributes are (when you use Emacs
from normal terminal (e.g. VT100) or terminal-emulator (e.g.
xterm):
  us/ue: start/end underline
  so/se: start/end inverse
  md/me: start/end bold

2. Information of attribute

Information of attributes are hold in a new buffer-local
variable 'attributed-region', which is nil or has the
following form:
	((0 . 0) (m_1 . a_1) ... (m_n . a_n))
where m_i is a marker to hold a position where attribute a_i
starts, a_i is a mask bits for each type of attribute:
Mask values of attributes are:
  1 -- underline
  2 -- inverse
  4 -- bold

However, it's not recommended that user modify this variable
directly, but you are expected to use the following
functions.

(defun attribute-on-region (attr &optional from to)
  "Set an character attribute ATTR within the region on.\n\
Currently supported attributes are 'underline', 'inverse', and 'bold'.\n\
If called from program, takes two optional arguments FROM and TO.\n\
If FROM or TO is NIL, (point-min) or (point-max) is used instead.\n\
Information of attribute is stored in a buffer local variable\n\
attributed-region, but manipulating these variables\n\
directly may cause serious problems."

(defun attribute-off-region (attr &optional from to)
  "Set an character attribute ATTR within the region off.\n\
See the function attribute-on-region for the detail."

(defun attribute-get-attribute (&optional pos)
  "Return a list of attribute ranges at POS.\n\
An attribute range is a list of attribute type, the starting point,\n\
and the ending point.\n\
POS is an optional argument and the default is the current point."