.Dd $Mdocdate$
.Dt rf 1
.Os
.
.Sh NAME
.Nm rf
.Nd alternative reference system for (t)roff
.
.Sh SYNOPSIS
.Nm
.Ar file
.
.Sh DESCIPTION
.Nm
is a reference system for troff and other roff derivatives.
It differs from
.Xr refer 1 ,
the traditional troff reference system,
in a couple important ways:
.Bl -enum
.It
References are not stored in a separate file.
They are defined via macros in the troff document itself, usually at the end.
.Pp
This means that you can move, copy and share your troff document without needing to worry about an additional reference file.
Furthermore, you never run the risk of accidentally losing the references attached to a document.
.It
.Nm
is around 150 lines of Perl.
If you find a bug or an (in your opinion) undesirable behavior in
.Nm ,
you can easily patch it.
.It
Finally,
.Nm
is much more simple and offers much more basic functionality than
.Xr refer 1 .
This means that you can learn all of it in five minutes.
.El
.Pp
The performance of
.Nm
primarily depends on the number of entries in the reference list at the end of the document.
On my HP Compaq dc5700 from 2007, the relationship between number of entries in the reference list and total execution time is roughly the following:
.Bl -column "EntriesXXXX" "TimeX" -offset indent
.It Em "Entries\ \ \ \ " Ta Em Time
.It    3          Ta    0.03s
.It    50         Ta    0.09s
.It    107        Ta    0.15s
.It    182        Ta    0.24s
.El
.Pp
I would deem it rare to have more than a couple of hundred references in a troff document.
.
.Sh USAGE
.Nm
is controlled by several macros, all consisting of one uppercase and one lowercase letter, beginning with either an
.Sq F
(format macros)
or an
.Sq R
(inline reference and reference list macros).
These are listed below in alphabetical order.
.Ss Format macros
.Bl -tag
.It Sy \&Ff
Defines the format for
.Dq full
inline references, which usually contain both author and year.
.Pp
Default: (%a %y)
.It Sy \&Fl
Defines the format for the reference list, which is usually located at the end of the document.
.Pp
Default: %a (%y). {\\fI%t\\fR}. {\\*Q%q\\*U}. %n, %d. %c: %p. {Available: %w.}
.It Sy \&Fx
Defines the format for
.Dq alternate
inline references, which usually contain only the year.
.Pp
Default: (%y)
.El
.Pp
For a description of the format syntax, see
.Sx FORMAT SYNTAX .
.
.Ss Inline reference macros
.Bl -tag
.It Sy \&Rf
Inserts a
.Dq full
inline reference, which usually contains both author and year.
.It Sy \&Rx
Inserts an
.Dq alternate
inline reference, which usually contains only the year.
.El
.Pp
What reference to refer to is specified by the rest of the line.
It is matched against the author, year and title of all references to find a match.
If only a weak match is found, a warning is printed on standard error.
.Pp
To include some punctuation character immediately after the inline reference, add a space before it:
.Bd -literal -offset indent
\&.Rf Johnson 92 .
.Ed
.Pp
To wrap the inline reference in parentheses, use the following syntax:
.Bd -literal -offset indent
\&.Rf Johnson 92 ) (
.Ed
.Pp
Additionally, any instance of
.Li ''
is replaced with the last word on the preceding line.
This allows the following shortcut:
.Bd -literal -offset indent
According to Johnson
\&.Rx '' 92 ,
there has been a gradual change in attitudes towards ...
.Ed
.
.Ss Reference list macros
.Bl -tag
.It Sy \&Ra
Adds to the list of
.Em authors
of the current reference.
Additionally,
.Sy \&Ra
marks the beginning of a new reference.
.Pp
Format: Surname(s), Forename(s)
.It Sy \&Rc
Defines the
.Em city
of publication.
.It Sy \&Rd
Defines the (detailed)
.Em date
of publication, not as a substitute for
.Sy \&Ry ,
but as a further specification.
For example, the day and month a newspaper article was published.
.It Sy \&Rn
Defines the
.Em newspaper
in which an article was published.
.It Sy \&Rp
Defines the
.Em publisher
of a book.
.It Sy \&Rq
Defines the (quoted)
.Em title
of an article.
.It Sy \&Rt
Defines the
.Em title
of a book.
.Ìt Sy \&Rw
Defines the (web)
.Em address
of an online resource.
.It Sy \&Ry
Defines the
.Em year
of publication.
.El
.Pp
Of these macros,
.Sy \&Ra
and
.Sy \&Ry
are the most important.
.Sh FORMAT SYNTAX
In a format definition, use a percent (%)
sigil followed by a single letter to interpolate any given field of the reference.
The letter following the percent sign corresponds to the second letter of the reference list macros described above.
For example:
.Bd -literal -offset indent
\&.Ff (%a, %y)      \\" (Author, Year)
.Ed
.Pp
By wrapping an interpolation in braces, you can specify a prefix and/or suffix that should be included only if the interpolation is successful.
For example:
.Bd -literal -offset indent
\&.Ff (%a{, %y}).   \\" Here, ', ' is removed if there is no year.
.Ed
.Pp
Note that all fields are inserted literally, except
.Em %a ,
from which the forenames of the authors are removed.
.Pp
Finally, you usually don't need to worry about excessive spaces and stray punctuation marks, as
.Nm
removes many of these these automatically.
.
.Sh AUTHORS
.Nm
was written by John Ankarström
.Aq Mt john (on) ankarstrom.se .