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FUNNELWEB MANUAL WEB PAGE
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=========================
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Copyright (c) Ross N. Williams 1992,1999. All rights reserved.
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Permission is granted to redistribute and use this manual in
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any medium, with or without modification, provided that all
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and all legal notices) are preserved on all copies, that all
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modifications since the manual's original release by Ross N.
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Williams (www.ross.net) consist of translations or other
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content. THIS MANUAL IS PROVIDED "AS IS" AND WITHOUT ANY
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<TITLE>5.7 Efficiency Notes</TITLE>
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<A HREF="index.html"><FONT COLOR="#FFFFFF"><B>Tutorial</B></FONT></A><BR>
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<A HREF="intro.html"><FONT COLOR="#FFFFFF">1 Introduction</FONT></A><BR>
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<A HREF="macro.html"><FONT COLOR="#FFFFFF">2 Macros</FONT></A><BR>
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<A HREF="type.html"><FONT COLOR="#FFFFFF">3 Typesetting</FONT></A><BR>
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<A HREF="example.html"><FONT COLOR="#FFFFFF">4 Example</FONT></A><BR>
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<A HREF="hints.html"><FONT COLOR="#FFFFFF">5 Hints</FONT></A><BR>
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<A HREF="examples.html"><FONT COLOR="#FFFFFF">6 Examples</FONT></A><BR>
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<A HREF="web.html"><FONT COLOR="#FFFFFF">7 Webmaking</FONT></A><BR>
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<A HREF="search.html"><FONT COLOR="#FFFFFF"><B>SEARCH</B></FONT></A><BR>
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<P><FONT SIZE="5">5.7 Efficiency Notes</FONT><BR>
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<P>The following notes are worth keeping in mind when
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<P><BLOCKQUOTE><B>Memory:</B> When
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FunnelWeb processes an input file, it reads the entire input
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file, and all the included files into memory. (Note: If a
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file is included n times, FunnelWeb keeps n copies in
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memory). This organization does not pose a constraint on
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machines with large memories, but could present a problem on
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the smaller machines such as the PC.</BLOCKQUOTE>
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<P><BLOCKQUOTE><B>Speed:</B> FunnelWeb is not a
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slow program. However, it is not particularly fast either.
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If the speed at which FunnelWeb runs is important to you,
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then the thing to keep in mind is that FunnelWeb has been
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optimized to deal efficiently with large slabs of text.
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FunnelWeb treats input files as a sequence of text slabs and
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special sequences (e.g. <SAMP>@+</SAMP>) and whenever it hits
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a special sequence, it has to stop and think. Thus, while a
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ten megabyte text slab would be manipulated as a single
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token, in a few milliseconds, a similar ten megabyte chunk
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filled with special sequences would take a lot longer. If
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FunnelWeb is running slowly, look to see if the input
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contains a high density of special sequences. This can
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sometimes happen if FunnelWeb is being used as a backend
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macro processor and its input is being generated
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automatically by some other program.</BLOCKQUOTE>
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<P><BLOCKQUOTE><B>Macro
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expansion:</B> When tangling
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(expanding macros), FunnelWeb never expands a macro
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expression into memory; it always writes it to the product
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file as it goes. This is a powerful fact, because it means
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that you can write macros containing an unlimited amount of
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text, and pass such macros as parameters to other macros
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without becoming concerned about overflowing some kind of
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buffer memory. In short, FunnelWeb does not impose any
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limits on the size of macro bodies or their expansions.</BLOCKQUOTE>
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<A HREF="copyright.html">Copyright © Ross N. Williams 1992,1999. All rights reserved.</A><BR>
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