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
|
<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>3.1 Basic Input File Processing</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="../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="../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>Reference</B></FONT></A><BR>
<A HREF="intro.html"><FONT COLOR="#FFFFFF">1 Introduction</FONT></A><BR>
<A HREF="interface.html"><FONT COLOR="#FFFFFF">2 Interface</FONT></A><BR>
<A HREF="scanner.html"><FONT COLOR="#FFFFFF">3 Scanner</FONT></A><BR>
<A HREF="parser.html"><FONT COLOR="#FFFFFF">4 Parser</FONT></A><BR>
<A HREF="analyser.html"><FONT COLOR="#FFFFFF">5 Analyser</FONT></A><BR>
<A HREF="tangle.html"><FONT COLOR="#FFFFFF">6 Tangle</FONT></A><BR>
<A HREF="weave.html"><FONT COLOR="#FFFFFF">7 Weave</FONT></A><BR>
<A HREF="shell.html"><FONT COLOR="#FFFFFF">8 Shell</FONT></A><BR>
<A HREF="commands.html"><FONT COLOR="#FFFFFF">9 Commands</FONT></A><BR>
<A HREF="glossary.html"><FONT COLOR="#FFFFFF">10 Glossary</FONT></A><BR>
<A HREF="references.html"><FONT COLOR="#FFFFFF">11 References</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 Reference Manual"
HSPACE="0" VSPACE="0"></A>
<P><FONT SIZE="5">3.1 Basic Input File Processing</FONT><BR>
<P>In order to read in an input file or include file, the
scanner calls a submodule called the <STRONG>mapper</STRONG>
that reads a file in and creates a contiguous copy of it in
memory. The scanner then performs three checks on the file,
the first (file termination) of which is performed before
scanning commences, and the other two of which take place
during scanning before each line is scanned.
<P><BLOCKQUOTE><B>File
Termination:</B> The first check the
scanner makes is whether the file
is terminated properly. A file is considered to be properly
terminated if it either contains no lines, or if the last
line in the file is terminated by an end-of-line marker. If
the scanner detects that an input file is not properly
terminated, it adds an end-of-line marker itself (to the
copy in memory only).</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Unprintable Characters:</B> The second check
the scanner makes is for
unprintable characters (ASCII 0--31 and 127--255 (except for
EOL(10))) which it flags as errors and replaces by question
marks.</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Line Lengths:</B> The third check the scanner
makes is input line length. When
FunnelWeb starts up, a default maximum input line length of
80 is set. This can be changed dynamically during scanning
using a <SAMP>@p maximum_input_line_length</SAMP> pragma. If
the number of characters on a line (not including the end of
line marker) exceeds this limit, FunnelWeb generates an
error.</BLOCKQUOTE>
<P>
<TABLE WIDTH="100%">
<TR>
<TD ALIGN="left" VALIGN="bottom"><A HREF="scanner.html"><IMG SRC="binary/fw_up.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Up"></A></TD>
<TD ALIGN="center" VALIGN="bottom"><A HREF="scanner.html"><IMG SRC="binary/fw_up.gif" HEIGHT="32" WIDTH="32" BORDER="0" ALT="Up"></A></TD>
<TD ALIGN="right" VALIGN="bottom"><A HREF="scanner_special.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>
<A HREF="copyright.html">Copyright © Ross N. Williams 1992,1999. All rights reserved.</A><BR>
</FONT>
</FONT>
</TD>
</TR>
</TABLE>
</FONT>
</BODY>
<!-- *********************************************************************** -->
<!-- End Of A FunnelWeb Manual Web Page (www.ross.net/funnelweb/) -->
<!-- *********************************************************************** -->
</HTML>
|
