1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
<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>3.3 Hierarchical Structure</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="../developer/index.html"
TARGET="funnelwebdeveloper"
onClick="window.open('','funnelwebdeveloper','location,status,menubar,scrollbars,resizable',false).focus(); return true;"
><FONT COLOR="#FFFFFF"><B>Developer</B></FONT></A><BR>
<BR>
<A HREF="index.html"><FONT COLOR="#FFFFFF"><B>Tutorial</B></FONT></A><BR>
<A HREF="intro.html"><FONT COLOR="#FFFFFF">1 Introduction</FONT></A><BR>
<A HREF="macro.html"><FONT COLOR="#FFFFFF">2 Macros</FONT></A><BR>
<A HREF="type.html"><FONT COLOR="#FFFFFF">3 Typesetting</FONT></A><BR>
<A HREF="example.html"><FONT COLOR="#FFFFFF">4 Example</FONT></A><BR>
<A HREF="hints.html"><FONT COLOR="#FFFFFF">5 Hints</FONT></A><BR>
<A HREF="examples.html"><FONT COLOR="#FFFFFF">6 Examples</FONT></A><BR>
<A HREF="web.html"><FONT COLOR="#FFFFFF">7 Webmaking</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="../reference/index.html"><IMG SRC="binary/title.gif"
WIDTH="302" HEIGHT="24"
BORDER="0" ALT="FunnelWeb Tutorial Manual"
HSPACE="0" VSPACE="0"></A>
<P><FONT SIZE="5">3.3 Hierarchical Structure</FONT><BR>
<P>The tree structure is one of the most effective
structuring tools that exists, deriving its power from the
principal of divide and conquor. So effective is it that the
internal organization of most technical books are tree
structures which are concisely summarized in the table of
contents. In contrast, computer programs are usually
presented as flat sequences of text to be consumed by an
anonymous compiler.
<P>In order to bring program documentation up to the
structural sophistication commonplace in technical books,
FunnelWeb provides five levels of section
headings implemented by the five
special sequences <SAMP>@A</SAMP>,
<SAMP>@B</SAMP>, <SAMP>@C</SAMP>, <SAMP>@D</SAMP>, and
<SAMP>@E</SAMP>. These must always appear at the start of a
line. <SAMP>@A</SAMP> is the highest level section (e.g. like
LaTeX's <SAMP>\chapter</SAMP>) and <SAMP>@E</SAMP> is the
lowest level section (e.g. like LaTeX's
<SAMP>\subsubsubsection</SAMP>). Section headings can
appear anywhere in the free text of a FunnelWeb input file
(i.e. anywhere except inside a macro definition).
<P>Each section heading in a
FunnelWeb document has an associated name. The name of a
section can be provided explicitly by supplying it delimited
by <SAMP>@<</SAMP> and <SAMP>@></SAMP> immediately
after the section sequence (e.g. <SAMP>@A</SAMP>), or
implicitly by not providing an explicit name, in which case
the section takes the name of the first macro defined
between the section header in question and the following
section header. An error is generated if a section has not
been given an explicit name and does not contain any macro
definitions. Here are some example headings:
<P>
<PRE>
@A@<Feed the Penguins and Save the World@>
@B@<Feed the Penguins@>
@C@<Feed the little penguins@>
@C@<Feed the big penguins@>
@B@<Save the World@>
@C@<Save Europe@>
@C@<Save Africa@>
@C This heading hasn't been given an
explicit name, but will inherit the name
<SAMP>Save the rest of the world</SAMP>
from the macro definition below.
@$@<Save the rest of the world@>@Z==@{...@}
</PRE>
<P>The feature of having unnamed sections inherit the name
of the first macro defined within their scope is present
because a common style of writing in FunnelWeb is to have
one section per macro definition. Because, under this style,
each section describes a single macro, it usually turns out
that the macro name makes a good name for the section too.
The inheritance mechanism prevents duplication of the
name.
<P>Apart from the requirement that each section have an
explicit or implicit name and that its special sequence
appear at the start of a line, the only other restriction on
section headings is that a section heading at level n
cannot appear immediately after a section heading at level
n-1 or less. In other words, the hierarchy cannot be
broken. For example, an <SAMP>@C</SAMP> cannot appear after an
<SAMP>@A</SAMP> heading unless there is an intervening
<SAMP>@B</SAMP> heading.
<P>
<PRE>
@A@<The Top Heading@>
@C@<Level C here is not allowed after an A@>
</PRE>
<P>This rule extends to the start of the file; if there
are any headings at all, the first one must be an
<SAMP>@A</SAMP> heading. The following file, while short, is
in error.
<P>
<PRE>
This FunnelWeb input file is in error
because its first section heading
is at level C rather than level A.
@C@<2@>
</PRE>
<P>
<TABLE WIDTH="100%">
<TR>
<TD ALIGN="left" VALIGN="bottom"><A HREF="type_independence.html"><IMG SRC="binary/fw_left.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Prev"></A></TD>
<TD ALIGN="center" VALIGN="bottom"><A HREF="type.html"><IMG SRC="binary/fw_up.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Up"></A></TD>
<TD ALIGN="right" VALIGN="bottom"><A HREF="type_printed.html"><IMG SRC="binary/fw_right.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Next"></A></TD>
</TR>
</TABLE>
<HR>
<FONT SIZE="2">
<A HREF="mailto:webmaster@ross.net">Webmaster</A>
<A HREF="copyright.html">Copyright © 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>
|
