-.\" $Id: mdoc.3,v 1.9 2009/02/23 15:19:47 kristaps Exp $
+.\" $Id: mdoc.3,v 1.13 2009/02/27 09:14:02 kristaps Exp $
.\"
.\" Copyright (c) 2009 Kristaps Dzonsons <kristaps@kth.se>
.\"
.\" TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
.\" PERFORMANCE OF THIS SOFTWARE.
.\"
-.Dd $Mdocdate: February 23 2009 $
+.Dd $Mdocdate: February 27 2009 $
.Dt mdoc 3
.Os
.\" SECTION
.Xr mdoc 7
and
.Xr mdoc.samples 7
-manuals.
+manuals. Documents with
+.Xr refer 1 ,
+.Xr eqn 1
+and other pre-processor sections aren't accomodated.
.\" PARAGRAPH
.Pp
.Nm
.Sx Functions
and
.Sx Variables
-available to programmers. The last sub-section,
+available to programmers. Following that,
+.Sx Character Encoding
+describes input format. Lastly,
.Sx Abstract Syntax Tree ,
documents the output tree.
.\" SUBSECTION
An array of string-ified token argument names.
.El
.\" SUBSECTION
+.Ss Character Encoding
+The
+.Xr mdoc 3
+library accepts only printable ASCII characters as defined by
+.Xr isprint 3 .
+Non-ASCII character sequences are delimited in various ways. All are
+preceeded by an escape character
+.Sq \\
+and followed by either an open-parenthesis
+.Sq \&(
+for two-character sequences; an open-bracket
+.Sq \&[
+for n-character sequences (terminated at a close-bracket
+.Sq \&] ) ;
+an asterisk and open-parenthesis
+.Sq \&*(
+for two-character sequences;
+an asterisk and non-open-parenthesis
+.Sq \&*
+for single-character sequences; or one of a small set of standalone
+single characters for other escapes.
+.\" PARAGRAPH
+.Pp
+Examples:
+.Pp
+.Bl -tag -width "XXXXXXXX" -offset "XXXX" -compact
+.\" LIST-ITEM
+.It \\*(<=
+prints
+.Dq \*(<=
+.Pq greater-equal
+.\" LIST-ITEM
+.It \\(<-
+prints
+.Dq \(<-
+.Pq left-arrow
+.\" LIST-ITEM
+.It \\[<-]
+also prints
+.Dq \(<-
+.Pq left-arrow
+.\" LIST-ITEM
+.It \\*(Ba
+prints
+.Dq \*(Ba
+.Pq bar
+.\" LIST-ITEM
+.It \\*q
+prints
+.Dq \*q
+.Pq double-quote
+.El
+.\" PARAGRAPH
+.Pp
+All escaped sequences are syntax-checked, but it's up to the front-end
+system to correctly render them to the output device.
+.\" SUBSECTION
.Ss Abstract Syntax Tree
The
.Nm