NAME

       prerex_format -- a format for prerequisite-chart descriptions

DESCRIPTION

       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).

TERMINOLOGY

       A  prerequisite chart consists of a number of course boxes, linked by arrows.  Courses are either half or
       full, and may be required or optional (or neither).  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.

STRUCTURE

       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.

COURSE BOXES

       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}

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

       \optfullcourse 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}

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

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

MINI COURSE BOXES AND TEXT

       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

       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.

COORDINATE GRID

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

       \grid

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

WEB LINKS

       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,

       \renewcommand{\CourseURL}[3]{http://www.cs.queensu.ca/undergraduate/courses/#3.html}

       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.

AUTHOR

       R. D. Tennent (rdt@cs.queensu.ca)

SEE ALSO

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

prerex_format                                      2012-03-21                                          PREREX(5)