=================================================================== RCS file: /cvs/mandoc/eqn.7,v retrieving revision 1.38 retrieving revision 1.39 diff -u -p -r1.38 -r1.39 --- mandoc/eqn.7 2019/04/23 17:57:49 1.38 +++ mandoc/eqn.7 2020/01/10 11:55:04 1.39 @@ -1,4 +1,4 @@ -.\" \$Id: eqn.7,v 1.38 2019/04/23 17:57:49 schwarze Exp \$ +.\" \$Id: eqn.7,v 1.39 2020/01/10 11:55:04 schwarze Exp \$ .\" .\" Copyright (c) 2011 Kristaps Dzonsons .\" Copyright (c) 2014 Ingo Schwarze @@ -15,7 +15,7 @@ .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" -.Dd \$Mdocdate: April 23 2019 \$ +.Dd \$Mdocdate: January 10 2020 \$ .Dt EQN 7 .Os .Sh NAME @@ -44,28 +44,16 @@ specification (see .Sx SEE ALSO for references). .Pp -Equations within -.Xr mdoc 7 -or -.Xr man 7 -documents are enclosed by the standalone -.Sq \&.EQ -and -.Sq \&.EN -tags. -Equations are multi-line blocks consisting of formulas and control -statements. -.Sh EQUATION STRUCTURE -Each equation is bracketed by -.Sq \&.EQ -and -.Sq \&.EN -strings. -.Em Note : -these are not the same as -.Xr roff 7 -macros, and may only be invoked as -.Sq \&.EQ . +An equation starts with an input line containing exactly the characters +.Sq \&.EQ , +may contain multiple input lines, and ends with an input line +containing exactly the characters +.Sq \&.EN . +Equivalently, an equation can be given in the middle of a single +text input line by surrounding it with the equation delimiters +defined with the +.Cm delim +statement. .Pp The equation grammar is as follows, where quoted strings are case-sensitive literals in the input: @@ -178,6 +166,25 @@ statement is a synonym for while .Cm tdefine is discarded. +.It Cm delim +This statement takes a string argument consisting of two bytes, +to be used as the opening and closing delimiters for equations +in the middle of text input lines. +Conventionally, the dollar sign is used for both delimiters, +as follows: +.Bd -literal -offset indent +\&.EQ +delim \$\$ +\&.EN +An equation like \$sin pi = 0\$ can now be entered +in the middle of a text input line. +.Ed +.Pp +The special statement +.Cm delim off +temporarily disables previously declared delimiters and +.Cm delim on +reenables them. .It Cm gfont Set the default font of subsequent output. Its syntax is as follows: