6.  How it Works

Nothing out of the ordinary happens for PostScript file generation. In general, some user-defined preprocessors may be applied before the normal preprocessors to the c.* files to produce troff input.

To create HTML files, unroff reads both macro definitions and the output of the preprocessors, and creates the HTML files for each c.* file. mk_links links the files together and includes the website information.

The data flow through the used tools is described in the following figure.

As you see, there is nothing special if you are producing a PostScript file. As usual all used tools are connected via pipe. A few preprocessors are doing there job, before the original preprocessors -- pic(1). eqn(1) and tbl(1) -- are producing troff-input.

troff(1) reads this input and the macro definfitions

general macro packages:

me -- macros for formatting papers,
ms -- text formatting macros
mm -- text formatting (memorandum) macros
man -- macros to format Reference Manual pages etc. and

local macro packages:

letter -- macros to format letters ("Mit freundlichen Grüßen" and of course project specific macros.

to produce a PostScript file.

If you take a look to the HTML creation part, you will see it looks a little bit different. unroff(1) reads the

• macro definitonions,
• the output of the preprocessors like grap(1),and
• a HTML info file -- see Figure 3 -- wich includes global information and creates s raw HTML files. These files doesn't include links to other files, mail links, copyright notice etc.

mk_links(1) links the files together and includes the HTML info.

 1      MAIL_TO= your_email_address             # for example: hpb@cs.rit.edu
 2      TITLE="Web page Titel"                  # for example: "Compiler Design I"
 3      COPYRIGHT="you name"                    # for example: "Hans-Peter Bischof"
 4      DIR_IN_PUBLIC_HTML="the_public_html_directory"
 5                                              # for example: "~/public_html/cd_I"

Figure 1: Html Info File

It's not possible to visualize complicated structures like line graphics, math etc in HTML. Therefore unroff(1) is using pic(1), eqn(1), tbl(1), and to convert these part of the document into a gif file and include the gif file in the HTML document.

It is possible to create simple tables in HTML, but I believe it's not worth do go an extra way for this problem.

Last modified: 24/November/98 (09:40)