/usr/share/doc/swig2.0-doc/Devel/scanner.html is in swig2.0-doc 2.0.12-1ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 | <html>
<head>
<title>SWIG C Scanner</title>
</head>
<body>
<center>
<h1>SWIG C/C++ Scanning</h1>
<p>
David M. Beazley <br>
dave-swig@dabeaz.com<br>
January 11, 2007<br>
</b>
</center>
<h2>Introduction</h2>
This document describes functions that can be used to tokenize C/C++
input text. These functions are relatively low-level and are meant to
be used in the implementation of scanners that can be plugged into yacc or used for
other purposes. For instance, the preprocessor uses these functions to evaluate and test
constant expressions.
<p>
All of these functions are declared in <tt>Source/Swig/swigscan.h</tt>. This API is considered to be stable.
<h2>Creation and Deletion of Scanners</h2>
The following functions are used to create and destroy a scanner object. More than one scanner object can be created and used
as necessary.
<p>
<b><tt>Scanner *NewScanner()</tt></b>
<blockquote>
Creates a new scanner object. The scanner contains initially contains no text. To feed text to the scanner use <tt>Scanner_push()</tt>.
</blockquote>
<p>
<b><tt>Scanner *DelScanner()</tt></b>
<blockquote>
Deletes a scanner object.
</blockquote>
<h2>Scanner Functions</h2>
<p>
<b><tt>void Scanner_clear(Scanner *s)</tt></b>
<blockquote>
Clears all text from the scanner. This can be used to reset a scanner to its initial state, ready to receive new input text.
</blockquote>
<p>
<b><tt>void Scanner_push(Scanner *s, String *text)</tt></b>
<blockquote>
Pushes an input string into the scanner. Subsequent tokens will be
returned from the new string. If the scanner is already processing a
string, the pushed string takes precedence--in effect, interrupting
the scanning of the previous string. This behavior is used to
implement certain SWIG features such as the <tt>%inline</tt>
directive. Once the pushed string has been completely scanned, the
scanner will return to scanning the previous string (if any). The
scanning of text relies upon the DOH file interface to strings
(<tt>Getc()</tt>, <tt>Ungetc()</tt>, etc.). Prior to calling this
function, the input string should be set so that its file pointer is
in the location where you want scanning to begin. You may have to
use <tt>Seek()</tt> to set the file pointer back to the beginning of a
string prior to using this function.
</blockquote>
<p>
<b><tt>void Scanner_pushtoken(Scanner *s, int tokvalue, String_or_char *val)</tt></b>
<blockquote>
Pushes a token into the scanner. This exact token will be returned by the next call to <tt>Scanner_token()</tt>.
<tt>tokvalue</tt> is the integer token value to return and <tt>val</tt> is the token text to return. This
function is only used to handle very special parsing cases. For instance, if you need the scanner to
return a fictitious token into order to enter a special parsing case.
</blockquote>
<p>
<b><tt>int Scanner_token(Scanner *s)</tt></b>
<blockquote>
Returns the next token. An integer token code is returned (see table below) on success. If no more input text is
available 0 is returned. If a scanning error occurred, -1 is returned. In this case, error information can be
obtained using <tt>Scanner_errinfo()</tt>.
</blockquote>
<p>
<b><tt>String *Scanner_text(Scanner *s)</tt></b>
<blockquote>
Returns the scanned text corresponding to the last token returned by <tt>Scanner_token()</tt>. The returned string
is only valid until the next call to <tt>Scanner_token()</tt>. If you need to save it, make a copy.
</blockquote>
<p>
<b><tt>void Scanner_skip_line(Scanner *s)</tt></b>
<blockquote>
Skips to the end of the current line. The text skipped can be obtained using <tt>Scanner_text()</tt> afterwards.
</blockquote>
<p>
<b><tt>void Scanner_skip_balanced(Scanner *s, int startchar, int endchar)</tt></b>
<blockquote>
Skips to the end of a block of text denoted by starting and ending characters. For example, <tt>{</tt> and <tt>}</tt>. The
function is smart about how it skips text. String literals and comments are ignored. The function also is aware of nesting. The
skipped text can be obtained using <tt>Scanner_text()</tt> afterwards. Returns 0 on success, -1 if no matching <tt>endchar</tt> could be found.
</blockquote>
<p>
<b><tt>void Scanner_set_location(Scanner *s, int startchar, int endchar)</tt></b>
<blockquote>
Changes the current filename and line number of the scanner.
</blockquote>
<p>
<b><tt>String *Scanner_file(Scanner *s)</tt></b>
<blockquote>
Gets the current filename associated with text in the scanner.
</blockquote>
<p>
<b><tt>int Scanner_line(Scanner *s)</tt></b>
<blockquote>
Gets the current line number associated with text in the scanner.
</blockquote>
<p>
<b><tt>int Scanner_start_line(Scanner *s)</tt></b>
<blockquote>
Gets the starting line number of the last token returned by the scanner.
</blockquote>
<p>
<b><tt>void Scanner_idstart(Scanner *s, char *idchar)</tt></b>
<blockquote>
Sets additional characters (other than the C default) that may be used to start C identifiers. <tt>idchar</tt> is a string
containing the characters (e.g., "%@"). The purpose of this function is to up special keywords such as "%module" or "@directive" as
simple identifiers.
</blockquote>
<p>
<b><tt>String *Scanner_errmsg(Scanner *s)</tt></b>
<blockquote>
Returns the error message associated with the last scanner error (if any). This will only return a meaningful result
if <tt>Scanner_token()</tt> returned -1.
</blockquote>
<p>
<b><tt>int Scanner_errline(Scanner *s)</tt></b>
<blockquote>
Returns the line number associated with the last scanner error (if any). This will only return a meaningful result
if <tt>Scanner_token()</tt> returned -1. The line number usually corresponds to the starting line number of a particular
token (e.g., for unterminated strings, comments, etc.).
</blockquote>
<p>
<b><tt>int Scanner_isoperator(int tokval)</tt></b>
<blockquote>
A convenience function that returns 0 or 1 depending on whether <tt>tokval</tt> is a valid C/C++ operator (i.e., a candidate for
operator overloading).
</blockquote>
<p>
<b><tt>void Scanner_freeze_line(int val)</tt></b>
<blockquote>
Freezes the current line number depending upon whether or not <tt>val</tt> is 1 or 0. When the line number is frozen, newline characters will not result in
updates to the line number. This is sometimes useful in tracking line numbers through complicated macro expansions.
</blockquote>
<h2>Token Codes</h2>
The following table shows token codes returned by the scanner. These are integer codes returned by
the <tt>Scanner_token()</tt> function.
<blockquote>
<pre>
Token code C Token
------------------------- -------------
SWIG_TOKEN_LPAREN (
SWIG_TOKEN_RPAREN )
SWIG_TOKEN_SEMI ;
SWIG_TOKEN_COMMA ,
SWIG_TOKEN_STAR *
SWIG_TOKEN_TIMES *
SWIG_TOKEN_LBRACE {
SWIG_TOKEN_RBRACE }
SWIG_TOKEN_EQUAL =
SWIG_TOKEN_EQUALTO ==
SWIG_TOKEN_NOTEQUAL !=
SWIG_TOKEN_PLUS +
SWIG_TOKEN_MINUS -
SWIG_TOKEN_AND &
SWIG_TOKEN_LAND &&
SWIG_TOKEN_OR |
SWIG_TOKEN_LOR ||
SWIG_TOKEN_XOR ^
SWIG_TOKEN_LESSTHAN <
SWIG_TOKEN_GREATERTHAN >
SWIG_TOKEN_LTEQUAL <=
SWIG_TOKEN_GTEQUAL >=
SWIG_TOKEN_NOT ~
SWIG_TOKEN_LNOT !
SWIG_TOKEN_LBRACKET [
SWIG_TOKEN_RBRACKET ]
SWIG_TOKEN_SLASH /
SWIG_TOKEN_DIVIDE /
SWIG_TOKEN_BACKSLASH \
SWIG_TOKEN_POUND #
SWIG_TOKEN_PERCENT %
SWIG_TOKEN_MODULO %
SWIG_TOKEN_COLON :
SWIG_TOKEN_DCOLON ::
SWIG_TOKEN_DCOLONSTAR ::*
SWIG_TOKEN_LSHIFT <<
SWIG_TOKEN_RSHIFT >>
SWIG_TOKEN_QUESTION ?
SWIG_TOKEN_PLUSPLUS ++
SWIG_TOKEN_MINUSMINUS --
SWIG_TOKEN_PLUSEQUAL +=
SWIG_TOKEN_MINUSEQUAL -=
SWIG_TOKEN_TIMESEQUAL *=
SWIG_TOKEN_DIVEQUAL /=
SWIG_TOKEN_ANDEQUAL &=
SWIG_TOKEN_OREQUAL |=
SWIG_TOKEN_XOREQUAL ^=
SWIG_TOKEN_LSEQUAL <<=
SWIG_TOKEN_RSEQUAL >>=
SWIG_TOKEN_MODEQUAL %=
SWIG_TOKEN_ARROW ->
SWIG_TOKEN_ARROWSTAR ->*
SWIG_TOKEN_PERIOD .
SWIG_TOKEN_AT @
SWIG_TOKEN_DOLLAR $
SWIG_TOKEN_ENDLINE Literal newline
SWIG_TOKEN_ID identifier
SWIG_TOKEN_FLOAT Floating point with F suffix (e.g., 3.1415F)
SWIG_TOKEN_DOUBLE Floating point (e.g., 3.1415 )
SWIG_TOKEN_INT Integer (e.g., 314)
SWIG_TOKEN_UINT Unsigned integer (e.g., 314U)
SWIG_TOKEN_LONG Long integer (e.g., 314L)
SWIG_TOKEN_ULONG Unsigned long integer (e.g., 314UL)
SWIG_TOKEN_LONGLONG Long long integer (e.g., 314LL )
SWIG_TOKEN_ULONGLONG Unsigned long long integer (e.g., 314ULL)
SWIG_TOKEN_CHAR Character literal in single quotes ('c')
SWIG_TOKEN_STRING String literal in double quotes ("str")
SWIG_TOKEN_RSTRING Reverse quote string (`str`)
SWIG_TOKEN_CODEBLOCK SWIG code literal block %{ ... %}
SWIG_TOKEN_COMMENT C or C++ comment (// or /* ... */)
SWIG_TOKEN_ILLEGAL Illegal character
</pre>
</blockquote>
<b>Notes</b>
<ul>
<li>When more than one token code exist for the same token text, those codes are identical (e.g., <tt>SWIG_TOKEN_STAR</tt> and <tt>SWIG_TOKEN_TIMES</tt>).
<p>
<li>
String literals are returned in their exact representation in which escape codes (if any) have been interpreted.
<p>
<li>
All C identifiers and keywords are simply returned as <tt>SWIG_TOKEN_ID</tt>. To check for specific keywords, you will need to
add extra checking on the returned text.
<p>
<li>C and C++ comments include the comment starting and ending text (e.g., "//", "/*").
<p>
<li>The maximum token integer value is found in the constant <tt>SWIG_MAXTOKENS</tt>. This can be used if you wanted to create
an array or table for the purposes of remapping tokens to a different set of codes. For instance, if you are
using these functions to write a yacc-compatible lexer.
</ul>
</body>
</html>
|