Provided by: prerex_6.2-6.3.1-1_i386 bug


       prerex_format -- a format for prerequisite-chart descriptions


       This  manual  describes  the  format of prerequisite-chart descriptions
       that  can  be  processed  by  [pdf]latex  (normally  using  a  suitable
       prerex.sty(7)  style  file)  and edited using the prerex(1) interactive
       editor (or by any conventional text editor).


       A prerequisite chart consists of a number of course  boxes,  linked  by
       arrows.   Courses  are  either half or full, and may be required.  Each
       course box can contain a course code  (upper  left  corner),  a  course
       title (lower half), and timetable information (upper right corner).  An
       arrow can be either a prerequisite (solid), a corequisite (dotted),  or
       recommended   (dashed).    When   a   conventional   arrow   would   be
       inappropriate, a mini course just above a target box can be used.


       The file should contain exactly one instance of a LaTeX environment

       \begin{chart} instruction ... \end{chart}

       with at most one instruction per line.  Note that  a  program  such  as
       prerex(1)  analyzes prerex-format files without using TeX; for example,
       macro definitions will be ignored and macro calls will not be expanded.

       Instructions may be preceded by white space.  Lines that start  with  %
       are  treated as comments and ignored.  The order of instructions is not
       significant except that the instruction for the source and target box o
       an arrow should precede the instruction for the arrow.  The instruction
       formats are described in the following sections.


       The instructions producing course boxes have the following forms:

       \halfcourse x,y:{code}{title}{timetable}

       \fullcourse x,y:{code}{title}{timetable}

       \reqhalfcourse x,y:{code}{title}{timetable}

       \reqfullcourse x,y:{code}{title}{timetable}

       where x,y are the coordinates of the centerpoint of the  box,  relative
       to  the origin of the coordinate system at the lower-left corner of the
       diagram.  The code, title, and timetable arguments are arbitrary (well-
       bracketed) text, possibly with LaTeX markup.

       The  following  are  similar but take an additional argument to specify
       the (non-default) background color of the course box:

              \halfcoursec x,y:{code}{title}{timetable}{color}

              \fullcoursec x,y:{code}{title}{timetable}{color}

              \reqhalfcoursec x,y:{code}{title}{timetable}{color}

              \reqfullcoursec x,y:{code}{title}{timetable}{color}


       A mini course is produced by an instruction of the form

       \mini x,y:{code}

       A text line is inserted into the chart by an instruction of the form

       \text x,y:{line-of-text}

       The maximum allowed length of a course-code may  be  smaller  that  the
              maximum allowed for a line of text.


       Arrows  between  course  boxes  (or  from  a  mini to a course box) are
       produced by instructions of the form

       \prereq x0,y0,x1,y1:

       \coreq x0,y0,x1,y1:

       \recomm x0,y0,x1,y1:

       These produce, respectively, solid, dotted, and dashed arrows from  the
       course  box  (or  mini) centered at coordinates x0,y0 to the course box
       centered at coordinates x1,y1.

       In some implementations, certain arrows  by  default  have  a  non-zero
       curvature.   It  is  possible  to  override the default curvature for a
       particular arrow by using the instructions

       \prereqc x0,y0,x1,y1;c:

       \coreqc x0,y0,x1,y1;c:

       \recommc x0,y0,x1,y1;c:

       where c is an  integer  in  the  range  0-100  specifying  the  desired
       curvature;  for  example,  c=0 will produce a straight arrow. To change
       the  default   curvature,   the   user   program   may   redefine   the
       \DefaultCurvature command.


       The  following  instruction produces a coordinate grid, which is useful
       for editing a diagram:


       This is normally placed before all the other instructions so that  grid
       lines  are  in  the  background,  covered  by  course boxes, minis, and


       Course boxes may be linked to web addresses.  The URL for course  boxes
       may  be  set  by  the  user  by redefining the \CourseURL command; when
       called for a course box, it is supplied with three arguments, the x and
       y  coordinates  of the box, mini, or textline, and the code argument of
       the course box. For example,


       is  appropriate  for  courses  at  the  School  of  Computing,  Queen's
       University.  The first  two  arguments  can  be  used  to  display  the
       coordinates  of  a box, mini, or textline in some PDF viewers while the
       mouse hovers over it when the source file is being edited.


       R. D. Tennent (


       prerex(1), prerex.sty(7).