===================================================================
RCS file: /cvs/mandoc/roff.7,v
retrieving revision 1.1
retrieving revision 1.4
diff -u -p -r1.1 -r1.4
--- mandoc/roff.7	2010/05/16 19:08:11	1.1
+++ mandoc/roff.7	2010/05/17 02:01:05	1.4
@@ -1,4 +1,4 @@
-.\"	$Id: roff.7,v 1.1 2010/05/16 19:08:11 kristaps Exp $
+.\"	$Id: roff.7,v 1.4 2010/05/17 02:01:05 kristaps Exp $
 .\"
 .\" Copyright (c) 2010 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: May 16 2010 $
+.Dd $Mdocdate: May 17 2010 $
 .Dt ROFF 7
 .Os
 .Sh NAME
@@ -65,10 +65,57 @@ Thus, the following are equivalent:
 .Sh REFERENCE
 This section is a canonical reference of all macros, arranged
 alphabetically.
+.Ss \&am
+The syntax of this macro is the same as that of
+.Sx \&ig ,
+except that a leading argument must be specified.
+It is ignored, as are its children.
+.Ss \&ami
+The syntax of this macro is the same as that of
+.Sx \&ig ,
+except that a leading argument must be specified.
+It is ignored, as are its children.
+.Ss \&am1
+The syntax of this macro is the same as that of
+.Sx \&ig ,
+except that a leading argument must be specified.
+It is ignored, as are its children.
+.Ss \&de
+The syntax of this macro is the same as that of
+.Sx \&ig ,
+except that a leading argument must be specified.
+It is ignored, as are its children.
+.Ss \&dei
+The syntax of this macro is the same as that of
+.Sx \&ig ,
+except that a leading argument must be specified.
+It is ignored, as are its children.
+.Ss \&de1
+The syntax of this macro is the same as that of
+.Sx \&ig ,
+except that a leading argument must be specified.
+It is ignored, as are its children.
 .Ss \&if
-Begins a conditional.
-Has the following syntax:
+Begins a conditional that always evaluates to false.
+If a conditional is false, its children are not processed, but are
+syntactically interpreted to preserve the integrity of the input
+document.
+Thus,
 .Pp
+.D1 \&.if t \e .ig
+.Pp
+will discard the
+.Sq \&.ig ,
+which may lead to interesting results, but
+.Pp
+.D1 \&.if t \e .if t \e{\e
+.Pp
+will continue to syntactically interpret to the block close of the final
+conditional.
+Sub-conditionals, in this case, obviously inherit the truth value of
+the parent.
+This macro has the following syntax:
+.Pp
 .Bd -literal -offset indent -compact
 \&.if COND \e{\e
 BODY...
@@ -76,6 +123,10 @@ BODY...
 .Ed
 .Bd -literal -offset indent -compact
 \&.if COND \e{ BODY
+BODY... \e}
+.Ed
+.Bd -literal -offset indent -compact
+\&.if COND \e{ BODY
 BODY...
 \&.\e}
 .Ed
@@ -84,7 +135,8 @@ BODY...
 BODY
 .Ed
 .Pp
-COND is a conditional (TODO: document).
+COND is a conditional (for the time being, this always evaluates to
+false).
 .Pp
 If the BODY section is begun by an escaped brace
 .Sq \e{ ,
@@ -112,15 +164,76 @@ The scope of a conditional is always parsed, but only 
 conditional evaluates to true.
 .Pp
 Note that text subsequent a
+.Sq \&.\e}
+macro is discarded.
+Furthermore, if an explicit closing sequence
 .Sq \e}
-is discarded.
+is specified in a free-form line, the entire line is accepted within the
+scope of the prior macro, not only the text preceding the close.
 .Ss \&ig
-Ignore input until a
-.Sq \.\.
+Ignore input.
+Accepts the following syntax:
+.Pp
+.Bd -literal -offset indent -compact
+\&.ig
+BODY...
+\&..
+.Ed
+.Bd -literal -offset indent -compact
+\&.ig END
+BODY...
+\&.END
+.Ed
+.Pp
+In the first case, input is ignored until a
+.Sq \&..
 macro is encountered on its own line.
-Note that text subsequent the
-.Sq \.\.
+In the second case, input is ignored until a
+.Sq \&.END
+is encountered.
+Text subsequent the
+.Sq \&.END
+or
+.Sq \&..
 is discarded.
+.Pp
+Do not use the escape
+.Sq \e
+anywhere in the definition of END.
+It causes very strange behaviour.
+Furthermore, if you redefine a
+.Nm
+macro, such as
+.Pp
+.D1 \&.ig if
+.Pp
+the subsequent invocation of
+.Sx \&if
+will first signify the end of comment, then be invoked as a macro.
+This behaviour really shouldn't be counted upon.
+.Sh COMPATIBILITY
+This section documents compatibility between mandoc and other other
+troff implementations, at this time limited to GNU troff
+.Pq Qq groff .
+The term
+.Qq historic groff
+refers to groff versions before the
+.Pa doc.tmac
+file re-write
+.Pq somewhere between 1.15 and 1.19 .
+.Pp
+.Bl -dash -compact
+.It
+Historic groff did not accept white-space buffering the custom END tag
+for the
+.Sx \&ig
+macro.
+.It
+The
+.Sx \&if
+and family would print funny white-spaces with historic groff when
+depending on next-line syntax.
+.El
 .Sh AUTHORS
 The
 .Nm