File: design_structure.html

package info (click to toggle)
funnelweb-doc 3.2d-4.2
links: PTS
area: main
in suites: forky, sid, trixie
size: 3,744 kB
sloc: perl: 241; makefile: 23
file content (227 lines) | stat: -rw-r--r-- 6,914 bytes
parent folder | download | duplicates (5)
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
            "http://www.w3.org/TR/REC-html40/loose.dtd">

<HTML>
<!--
***********************************************************************
FUNNELWEB MANUAL WEB PAGE
=========================
Copyright (c) Ross N. Williams 1992,1999. All rights reserved.

Permission is granted to redistribute and use this manual in
any medium, with or without modification, provided that all
notices (including, without limitation, the copyright
notice, this permission notice, any record of modification,
and all legal notices) are preserved on all copies, that all
modifications are clearly marked, and that modified versions
are not represented as the original version unless all the
modifications since the manual's original release by Ross N.
Williams (www.ross.net) consist of translations or other
transformations that alter only the manual's form, not its
content. THIS MANUAL IS PROVIDED "AS IS" AND WITHOUT ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND
FITNESS FOR A PARTICULAR PURPOSE. TO THE EXTENT PERMITTED BY
LAW THERE IS ABSOLUTELY NO WARRANTY.

***********************************************************************
-->

<HEAD>
<TITLE>2.5 Document Structuring</TITLE>
<STYLE TYPE="text/css"> <!-- A {text-decoration: none} // --> </STYLE>
</HEAD>
<BODY BACKGROUND="binary/background.gif"
      BGCOLOR="#FFFFFF"
      TEXT="#000000"
      VLINK="#660000"
      LINK="#FF0000"
      ALINK="#CC0000">

<TABLE WIDTH="490">
<TR>
<TD WIDTH="130" VALIGN="top">
<IMG SRC="binary/d_clear.gif" ALT="" WIDTH="130" HEIGHT="1"><BR>

<FONT SIZE="2">
<BR>

<A HREF="http://www.ross.net/"
 TARGET="rosshome"
 onClick="window.open('','rosshome','location,status,menubar,scrollbars,resizable',false).focus(); return true;"
>
 <IMG SRC="binary/rossnet_logo.gif"
  WIDTH="64" HEIGHT="32"
  BORDER="0" ALT="RossNet"
  HSPACE="0" VSPACE="1"></A><BR>
<BR>

<A HREF="../index.shtml"
 TARGET="funnelweb"
 onClick="window.open('','funnelweb','location,status,menubar,scrollbars,resizable',false).focus(); return true;"
>
 <IMG SRC="binary/linklogo.gif"
  WIDTH="64" HEIGHT="32"
  BORDER="0" ALT="FunnelWeb"
  HSPACE="0" VSPACE="1"></A><BR>
<BR>
<TABLE CELLSPACING=0 CELLPADDING=0 BORDER=0><TR><TD BGCOLOR="#000000">
<A HREF="../reference/index.html"
 TARGET="funnelwebreference"
 onClick="window.open('','funnelwebreference','location,status,menubar,scrollbars,resizable',false).focus(); return true;"
><FONT COLOR="#FFFFFF"><B>Reference</B></FONT></A><BR>
<BR>
<A HREF="../tutorial/index.html"
 TARGET="funnelwebtutorial"
 onClick="window.open('','funnelwebtutorial','location,status,menubar,scrollbars,resizable',false).focus(); return true;"
><FONT COLOR="#FFFFFF"><B>Tutorial</B></FONT></A><BR>
<BR>
<A HREF="index.html"><FONT COLOR="#FFFFFF"><B>Developer</B></FONT></A><BR>
<A HREF="compile.html"><FONT COLOR="#FFFFFF">1 Compile</FONT></A><BR>
<A HREF="design.html"><FONT COLOR="#FFFFFF">2 Design</FONT></A><BR>
<A HREF="implement.html"><FONT COLOR="#FFFFFF">3 Implement</FONT></A><BR>
<A HREF="modify.html"><FONT COLOR="#FFFFFF">4 Modify</FONT></A><BR>
<A HREF="misc.html"><FONT COLOR="#FFFFFF">5 Misc</FONT></A><BR>
<A HREF="gpl.html"><FONT COLOR="#FFFFFF">6 Licence</FONT></A><BR>

<BR>
<A HREF="search.html"><FONT COLOR="#FFFFFF"><B>SEARCH</B></FONT></A><BR>
</FONT>
</TD></TR></TABLE>


</TD>
<TD WIDTH="360" VALIGN="top">
<FONT SIZE="3">


<A HREF="index.html"><IMG SRC="binary/title.gif"
 WIDTH="316" HEIGHT="24"
 BORDER="0" ALT="FunnelWeb Developer Manual"
 HSPACE="0" VSPACE="0"></A>
<P><FONT SIZE="5">2.5 Document Structuring</FONT><BR>


<P>Knuth's WEB system provided just two levels of headings,
and this scheme was used in FunnelWeb&nbsp;V1. However, experience
showed that there was a need for more levels. Here are some
syntaxes that were considered for implementing this:

<P><PRE>
@*@&lt;Main Program@&gt;
@**@&lt;Read the Message@&gt;
@***@&lt;Encrypt the Buffer@&gt;

@*@&lt;Main Program@&gt;
@*@*@&lt;Read the Message@&gt;
@*@*@*@&lt;Encrypt the Buffer@&gt;

@s@&lt;Main Program@&gt;
@ss@&lt;Read the Message@&gt;
@sss@&lt;Encrypt the Buffer@&gt;

@s@&lt;Main Program@&gt;
@s@s@&lt;Read the Message@&gt;
@s@s@s@&lt;Encrypt the Buffer@&gt;

@S@&lt;Main Program@&gt;
@SS@&lt;Read the Message@&gt;
@SSS@&lt;Encrypt the Buffer@&gt;

@S@&lt;Main Program@&gt;
@S@S@&lt;Read the Message@&gt;
@S@S@S@&lt;Encrypt the Buffer@&gt;

@1@&lt;Main Program@&gt;
@2@&lt;Read the Message@&gt;
@3@&lt;Encrypt the Buffer@&gt;
(using @A..@I@ as macro
 parameters or overload @1..@9)

@*@1@&lt;Main Program@&gt;
@*@2@&lt;Read the Message@&gt;
@*@3@&lt;Encrypt the Buffer@&gt;
(using @A..@I@ as macro parameters
 or overload @1..@9)

@A Main Program
@B Read the Message
@C Encrypt the Buffer

@*A Main Program
@*B Read the Message
@*C Encrypt the Buffer

The following is the syntax finally chosen.
@A@&lt;Main Program@&gt;
@B@&lt;Read the Message@&gt;
@C@&lt;Encrypt the Buffer@&gt;
</PRE>

<P>Choosing between these alternatives was not easy. The
following thoughts contributed to the decision.

<P>
<UL>

<LI> Syntaxes that require visual counting are probably
not a good idea.

<LI> Syntaxes that do not delimit the heading name
somehow are likely to cause problems where heading names are
omitted. Users will be tempted to start paragraphs after the
start of heading symbol, and the result is that the first
line of the paragraph will be sucked into the heading.

<LI> Overloading the <SAMP>@1</SAMP>, ...,
<SAMP>@9</SAMP> sequences is undesirable.

</UL>

<P>For these reasons, the following syntax was chosen:

<P>
<PRE>
@A@&lt;Main Program@&gt;
@B@&lt;Read the Message@&gt;
@C@&lt;Encrypt the Buffer@&gt;
@D@&lt;Encrypt the Buffer@&gt;
@E@&lt;Encrypt the Buffer@&gt;
</PRE>

<P>A maximum of five levels was chosen because it's
probably sufficient, and <SAMP>@F</SAMP> should be reserved
for <STRONG>F</STRONG>ile.


<P>
<TABLE WIDTH="100%">
<TR>
<TD ALIGN="left"   VALIGN="bottom"><A HREF="design_syntax.html"><IMG SRC="binary/fw_left.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Prev"></A></TD>
<TD ALIGN="center" VALIGN="bottom"><A HREF="design.html"><IMG SRC="binary/fw_up.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Up"></A></TD>
<TD ALIGN="right"  VALIGN="bottom"><A HREF="design_testing.html"><IMG SRC="binary/fw_right.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Next"></A></TD>
</TR>
</TABLE>



<P>
<HR>
<FONT SIZE="2">
<A HREF="mailto:webmaster@ross.net">Webmaster</A>&nbsp;&nbsp;&nbsp;
<A HREF="copyright.html">Copyright &copy; Ross N. Williams 1992,1999. All rights reserved.</A><BR>
</FONT>

</FONT>
</TD>
</TR>
</TABLE>


</BODY>

<!-- *********************************************************************** -->
<!--      End Of A FunnelWeb Manual Web Page (www.ross.net/funnelweb/)       -->
<!-- *********************************************************************** -->

</HTML>