PageRenderTime 44ms CodeModel.GetById 16ms RepoModel.GetById 0ms app.codeStats 0ms

/projects/javacc-5.0/www/doc/apiroutines.html

https://gitlab.com/essere.lab.public/qualitas.class-corpus
HTML | 552 lines | 473 code | 48 blank | 31 comment | 0 complexity | 24ef648269074348f145dea63daeb19f MD5 | raw file
    

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    2. 

  2. <html xmlns="http://www.w3.org/1999/xhtml">
    3. 

  3. <!--
    4. 

  4. 

  5. Copyright (c) 2006, Sun Microsystems, Inc.
    6. 

  6. All rights reserved.
    7. 

  7. 

  8. Redistribution and use in source and binary forms, with or without
    9. 

  9. modification, are permitted provided that the following conditions are met:
    10. 

  10. 

  11.     * Redistributions of source code must retain the above copyright notice,
    12. 

  12.       this list of conditions and the following disclaimer.
    13. 

  13.     * Redistributions in binary form must reproduce the above copyright
    14. 

  14.       notice, this list of conditions and the following disclaimer in the
    15. 

  15.       documentation and/or other materials provided with the distribution.
    16. 

  16.     * Neither the name of the Sun Microsystems, Inc. nor the names of its
    17. 

  17.       contributors may be used to endorse or promote products derived from
    18. 

  18.       this software without specific prior written permission.
    19. 

  19. 

  20. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    21. 

  21. AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    22. 

  22. IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    23. 

  23. ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
    24. 

  24. LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    25. 

  25. CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    26. 

  26. SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    27. 

  27. INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    28. 

  28. CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    29. 

  29. ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
    30. 

  30. THE POSSIBILITY OF SUCH DAMAGE.
    31. 

  31. 

  32. -->
    33. 

  33. <head>
    34. 

  34.  <title>JavaCC API Documentation</title>
    35. 

  35. <!-- Changed by: Michael Van De Vanter, 14-Jan-2003 -->
    36. 

  36. </head>
    37. 

  37. <body bgcolor="#FFFFFF" >
    38. 

  38. 

  39. <h1>JavaCC [tm]: API Routines</h1>
    40. 

  40. 

  41. <p>
    42. 

  42. This web page is a comprehensive list of all classes, methods,
    43. 

  43. and variables available for use by a JavaCC [tm] user.  These classes,
    44. 

  44. methods, and variables are typically used from the actions that
    45. 

  45. are embedded in a JavaCC grammar.  In the sample code used below,
    46. 

  46. it is assumed that the name of the generated parser is "TheParser".
    47. 

  47. </p>
    48. 

  48. 

  49. <h3>Non-Terminals in the Input Grammar</h3>
    50. 

  50. <p>
    51. 

  51. For each non-terminal NT in the input grammar file, the following method
    52. 

  52. is generated into the parser class:
    53. 

  53. </p>
    54. 

  54. <ul>
    55. 

  55. <li>
    56. 

  56. <strong><em>returntype</em> NT(<em>parameters</em>) throws ParseException;</strong>
    57. 

  57. </li>
    58. 

  58. </ul>
    59. 

  59. <p>
    60. 

  60. Here, <em>returntype</em> and <em>parameters</em> are what were specified
    61. 

  61. in the JavaCC input file in the definition of NT (where NT occurred on the
    62. 

  62. left-hand side).
    63. 

  63. </p>
    64. 

  64. <p>
    65. 

  65. When this method is called, the input stream is parsed to match this non-terminal.
    66. 

  66. On a successful parse, this method returns normally.  On detection of a parse
    67. 

  67. error, an error message is displayed and the method returns by throwing an exception
    68. 

  68. of the type ParseException.
    69. 

  69. </p>
    70. 

  70. <p>
    71. 

  71. <em>Note that all non-terminals in a JavaCC input grammar have equal status;
    72. 

  72. it is possible to parse to any non-terminal by calling the  non-terminal's method.
    73. 

  73. </em>
    74. 

  74. </p>
    75. 

  75. 

  76. <h3>API for Parser Actions</h3>
    77. 

  77. <ul>
    78. 

  78.   <li><strong> Token token;</strong>
    79. 

  79. <br />
    80. 

  80. This variable holds the last token consumed by the parser and can be used
    81. 

  81. in parser actions. This is <em>exactly</em> the same as the token returned by
    82. 

  82. <em>getToken(0)</em>.
    83. 

  83.   </li>
    84. 

  84. </ul>
    85. 

  85. <p>
    86. 

  86. In addition, the two methods - <em><a href="#getToken">getToken(int i)</a></em> and
    87. 

  87. <em><a href="#getNextToken">getNextToken()</a></em> can also be used in
    88. 

  88. actions to traverse the token list.
    89. 

  89. </p>
    90. 

  90. <h3>The Token Manager Interface</h3>
    91. 

  91. <p>
    92. 

  92. Typically, the token manager interface is not to be used.  Instead all access
    93. 

  93. must be made through the parser interface.  However, in certain situations -
    94. 

  94. such as if you are not building a parser and building only the token manager -
    95. 

  95. the token manager interface is useful.
    96. 

  96. The token manager provides the following routine:
    97. 

  97. </p>
    98. 

  98. <ul>
    99. 

  99. <li>
    100. 

  100. <strong>Token getNextToken() throws ParseError;</strong>
    101. 

  101. </li>
    102. 

  102. </ul>
    103. 

  103. <p>
    104. 

  104. Each call to this method returns the next token in the input stream. This
    105. 

  105. method throws a ParseError exception when there is a lexical error, i.e.,
    106. 

  106. it could not find a match for any of the specified tokens from the input
    107. 

  107. stream.  The type Token is described later.
    108. 

  108. </p>
    109. 

  109. 

  110. <h3>Constructors and Other Initialization Routines</h3>
    111. 

  111. <ul>
    112. 

  112. <li>
    113. 

  113. <strong>TheParser.TheParser(java.io.InputStream stream)</strong>
    114. 

  114. <br />
    115. 

  115. This creates a new parser object, which in turn creates a new token manager object
    116. 

  116. that reads its tokens from "stream".  This constructor is available only
    117. 

  117. when both the options USER_TOKEN_MANAGER and USER_CHAR_STREAM are false.
    118. 

  118. If the option STATIC is true, this constructor (along with other constructors)
    119. 

  119. can be called exactly once to create a single parser object.
    120. 

  120. </li>
    121. 

  121. <li>
    122. 

  122. <strong>TheParser.TheParser(CharStream stream)</strong>
    123. 

  123. <br />
    124. 

  124. Similar to the previous constructor, except that this one is available only
    125. 

  125. when the option USER_TOKEN_MANAGER is false and USER_CHAR_STREAM is true.
    126. 

  126. </li>
    127. 

  127. <li>
    128. 

  128. <strong>void TheParser.ReInit(java.io.InputStream stream)</strong>
    129. 

  129. <br />
    130. 

  130. This reinitializes an existing parser object.  In addition, it also reinitializes
    131. 

  131. the existing token manager object that corresponds to this parser object.  The result
    132. 

  132. is a parser object with the exact same functionality as one that was created
    133. 

  133. with the constructor above.  The only difference is that new objects are not
    134. 

  134. created.  This method is available only
    135. 

  135. when both the options USER_TOKEN_MANAGER and USER_CHAR_STREAM are false.
    136. 

  136. If the option STATIC is true, this (along with the other ReInit methods)
    137. 

  137. is the only way to restart a parse operation
    138. 

  138. for there is only one parser and all one can do is reinitialize it.
    139. 

  139. </li>
    140. 

  140. <li>
    141. 

  141. <strong>void TheParser.ReInit(CharStream stream)</strong>
    142. 

  142. <br />
    143. 

  143. Similar to the previous method, except that this one is available only
    144. 

  144. when the option USER_TOKEN_MANAGER is false and USER_CHAR_STREAM is true.
    145. 

  145. </li>
    146. 

  146. <li>
    147. 

  147. <strong>TheParser(TheParserTokenManager tm)</strong>
    148. 

  148. This creates a new parser object which uses an already created token manager object "tm" as
    149. 

  149. its token manager.  This constructor is only available if option USER_TOKEN_MANAGER is
    150. 

  150. false.  If the option STATIC is true, this constructor (along with other constructors)
    151. 

  151. can be called exactly once to create a single parser object.
    152. 

  152. </li>
    153. 

  153. <li>
    154. 

  154. <strong>TheParser(TokenManager tm)</strong>
    155. 

  155. <br />
    156. 

  156. Similar to the previous constructor, except that this one is available only
    157. 

  157. when the option USER_TOKEN_MANAGER is true.
    158. 

  158. </li>
    159. 

  159. <li>
    160. 

  160. <strong>void TheParser.ReInit(TheParserTokenManager tm)</strong>
    161. 

  161. <br />
    162. 

  162. This reinitializes an existing parser object with the token manager object "tm" as its
    163. 

  163. new token manager.  This method is only available if option USER_TOKEN_MANAGER is
    164. 

  164. false.  If the option STATIC is true, this (along with the other ReInit methods)
    165. 

  165. is the only way to restart a parse operation
    166. 

  166. for there is only one parser and all one can do is reinitialize it.
    167. 

  167. </li>
    168. 

  168. <li>
    169. 

  169. <strong>void TheParser.ReInit(TokenManager tm)</strong>
    170. 

  170. <br />
    171. 

  171. Similar to the previous method, except that this one is available only
    172. 

  172. when the option USER_TOKEN_MANAGER is true.
    173. 

  173. </li>
    174. 

  174. <li>
    175. 

  175. <strong>TheParserTokenManager.TheParserTokenManager(CharStream stream)</strong>
    176. 

  176. <br />
    177. 

  177. Creates a new token manager object initialized to read input from "stream".  When
    178. 

  178. the option STATIC is true, this constructor may be called only once.
    179. 

  179. This is available only when USER_TOKEN_MANAGER is false and USER_CHAR_STREAM
    180. 

  180. is true.  When USER_TOKEN_MANAGER is false and USER_CHAR_STREAM is false (the default situation),
    181. 

  181. a constructor similar to the one above is available with the type CharStream
    182. 

  182. replaced as follows:
    183. 

  183.  <ul>
    184. 

  184.   <li>
    185. 

  185. When JAVA_UNICODE_ESCAPE is false and UNICODE_INPUT is false, CharStream is
    186. 

  186. replaced by ASCII_CharStream.
    187. 

  187.   </li>
    188. 

  188.   <li>
    189. 

  189. When JAVA_UNICODE_ESCAPE is false and UNICODE_INPUT is true, CharStream is
    190. 

  190. replaced by UCode_CharStream.
    191. 

  191.   </li>
    192. 

  192.   <li>
    193. 

  193. When JAVA_UNICODE_ESCAPE is true and UNICODE_INPUT is false, CharStream is
    194. 

  194. replaced by ASCII_UCodeESC_CharStream.
    195. 

  195.   </li>
    196. 

  196.   <li>
    197. 

  197. When JAVA_UNICODE_ESCAPE is true and UNICODE_INPUT is true, CharStream is
    198. 

  198. replaced by UCode_UCodeESC_CharStream.
    199. 

  199.   </li>
    200. 

  200.  </ul>
    201. 

  201. </li>
    202. 

  202. <li>
    203. 

  203. <strong>void TheParserTokenManager.ReInit(CharStream stream)</strong>
    204. 

  204. <br />
    205. 

  205. Reinitializes the current token manager object to read input from "stream".  When
    206. 

  206. the option STATIC is true, this is the only way to restart a token manager operation.
    207. 

  207. This is available only when USER_TOKEN_MANAGER is false and USER_CHAR_STREAM
    208. 

  208. is true.  When USER_TOKEN_MANAGER is false and USER_CHAR_STREAM is false (the default situation),
    209. 

  209. a constructor similar to the one above is available with the type CharStream
    210. 

  210. replaced as follows:
    211. 

  211.  <ul>
    212. 

  212.   <li>
    213. 

  213. When JAVA_UNICODE_ESCAPE is false and UNICODE_INPUT is false, CharStream is
    214. 

  214. replaced by ASCII_CharStream.
    215. 

  215.   </li>
    216. 

  216.   <li>
    217. 

  217. When JAVA_UNICODE_ESCAPE is false and UNICODE_INPUT is true, CharStream is
    218. 

  218. replaced by UCode_CharStream.
    219. 

  219.   </li>
    220. 

  220.   <li>
    221. 

  221. When JAVA_UNICODE_ESCAPE is true and UNICODE_INPUT is false, CharStream is
    222. 

  222. replaced by ASCII_UCodeESC_CharStream.
    223. 

  223.   </li>
    224. 

  224.   <li>
    225. 

  225. When JAVA_UNICODE_ESCAPE is true and UNICODE_INPUT is true, CharStream is
    226. 

  226. replaced by UCode_UCodeESC_CharStream.
    227. 

  227.   </li>
    228. 

  228.  </ul>
    229. 

  229. </li>
    230. 

  230. </ul>
    231. 

  231. 

  232. <h3>The Token Class</h3>
    233. 

  233. <p>
    234. 

  234. The Token class is the type of token objects that are created by the token manager
    235. 

  235. after a successful scanning of the token stream.  These token objects are then
    236. 

  236. passed to the parser and are accessible to the actions in a JavaCC grammar usually
    237. 

  237. by grabbing the return value of a token.  The methods getToken and getNextToken
    238. 

  238. described below also give access to objects of this type.
    239. 

  239. </p>
    240. 

  240. <p>
    241. 

  241. Each Token object has the following fields and methods:
    242. 

  242. </p>
    243. 

  243. <ul>
    244. 

  244. <li>
    245. 

  245. <strong>int kind;</strong>
    246. 

  246. <br />
    247. 

  247. This is the index for this kind of token in the internal representation scheme
    248. 

  248. of JavaCC.  When tokens in the JavaCC input file are given labels, these labels
    249. 

  249. are used to generate "int" constants that can be used in actions.
    250. 

  250. The value 0 is always used to represent the predefined token &lt;EOF&gt;.  A
    251. 

  251. constant "EOF" is generated for convenience in the ...Constants file.
    252. 

  252. </li>
    253. 

  253. <li>
    254. 

  254. <strong>int beginLine, beginColumn, endLine, endColumn;</strong>
    255. 

  255. <br />
    256. 

  256. These indicate the beginning and ending positions of the token as it appeared
    257. 

  257. in the input stream.
    258. 

  258. </li>
    259. 

  259. <li>
    260. 

  260. <strong>String image;</strong>
    261. 

  261. <br />
    262. 

  262. This represents the image of the token as it appeared in the input stream.
    263. 

  263. </li>
    264. 

  264. <li>
    265. 

  265. <strong>Token next;</strong>
    266. 

  266. <br />
    267. 

  267. A reference to the next regular (non-special) token from the input
    268. 

  268. stream.  If this is the last token from the input stream, or if the
    269. 

  269. token manager has not read tokens beyond this one, this field is
    270. 

  270. set to null.
    271. 

  271. <br />
    272. 

  272. <br />
    273. 

  273. The description in the above paragraph holds only if this token is also a regular
    274. 

  274. token.  Otherwise, see below for a description of the contents of
    275. 

  275. this field.
    276. 

  276. <br />
    277. 

  277. <br />
    278. 

  278. Note: There are two kinds of tokens - regular and special.  Regular tokens are
    279. 

  279. the normal tokens that are fed to the parser.  Special tokens are other useful
    280. 

  280. tokens (like comments) that are not discarded (like white space).  For more
    281. 

  281. information on the different kinds of tokens
    282. 

  282. <a href="tokenmanager.html">please see the minitutorial on the token manager</a>.
    283. 

  283. </li>
    284. 

  284. <li>
    285. 

  285. <strong>Token specialToken;</strong>
    286. 

  286. <br />
    287. 

  287. This field is used to access special tokens that occur prior to this
    288. 

  288. token, but after the immediately preceding regular (non-special) token.
    289. 

  289. If there are no such special tokens, this field is set to null.
    290. 

  290. When there are more than one such special token, this field refers
    291. 

  291. to the last of these special tokens, which in turn refers to the next
    292. 

  292. previous special token through its specialToken field, and so on
    293. 

  293. until the first special token (whose specialToken field is null).
    294. 

  294. The next fields of special tokens refer to other special tokens that
    295. 

  295. immediately follow it (without an intervening regular token).  If there
    296. 

  296. is no such token, this field is null.
    297. 

  297. </li>
    298. 

  298. 

  299. <li>
    300. 

  300. <strong>public Object getValue();</strong>
    301. 

  301. <br />
    302. 

  302. An optional attribute value of the Token.
    303. 

  303. <br />
    304. 

  304. Tokens which are not used as syntactic sugar will often contain
    305. 

  305. meaningful values that will be used later on by the compiler or
    306. 

  306. interpreter. This attribute value is often different from the image.
    307. 

  307. Any subclass of Token that actually wants to return a non-null value can
    308. 

  308. override this method as appropriate.
    309. 

  309. </li>
    310. 

  310. 

  311. <li>
    312. 

  312. <strong>static final Token newToken(int ofKind);</strong>
    313. 

  313. <br />
    314. 

  314. <strong>static final Token newToken(int ofKind, String image);</strong>
    315. 

  315. <br />
    316. 

  316. Returns a new token object as its default behavior.  If you wish to
    317. 

  317. perform special actions when a token is constructed or create subclasses
    318. 

  318. of class Token and instantiate them instead, you can redefine this method
    319. 

  319. appropriately.  The only constraint is that this method returns a <em>new</em>
    320. 

  320. object of type Token (or a subclass of Token).
    321. 

  321. </li>
    322. 

  322. </ul>
    323. 

  323. 

  324. <h3>Reading Tokens from the Input Stream</h3>
    325. 

  325. <p>
    326. 

  326. There are two methods available for this purpose:
    327. 

  327. </p>
    328. 

  328. <ul>
    329. 

  329. <li>
    330. 

  330. <strong><a name="getNextToken">Token TheParser.getNextToken() throws ParseError</a></strong>
    331. 

  331. <br />
    332. 

  332. This method returns the next available token in the input stream and moves
    333. 

  333. the token pointer one step in the input stream (i.e., this changes the state
    334. 

  334. of the input stream).  If there are no more tokens available in the input
    335. 

  335. stream, the exception ParseError is thrown.  Care must be taken when calling
    336. 

  336. this method since it can interfere with the parser's knowledge of the state
    337. 

  337. of the input stream, current token, etc.
    338. 

  338. </li>
    339. 

  339. <li>
    340. 

  340. <strong><a name="getToken">Token TheParser.getToken(int index) throws ParseError</a></strong>
    341. 

  341. <br />
    342. 

  342. This method returns the index-th token from the current token ahead in the
    343. 

  343. token stream.  If index is 0, it returns the current token (the last token
    344. 

  344. returned by getNextToken or consumed by the parser); if index is 1, it returns
    345. 

  345. the next token (the next token that will be returned by getNextToken of consumed
    346. 

  346. by the parser) and so on.  The index parameter cannot be negative.  This method
    347. 

  347. does not change the input stream pointer (i.e., it does not change the
    348. 

  348. state of the input stream).  If an attempt is made to access a token beyond the
    349. 

  349. last available token, the exception ParseError is thrown.
    350. 

  350. If this method is called from a semantic lookahead specification, which in turn
    351. 

  351. is called during a lookahead determination process, the current token is temporarily
    352. 

  352. adjusted to be the token currently being inspected by the lookahead process.
    353. 

  353. For more details,
    354. 

  354. <a href="lookahead.html">please see the minitutorial on using lookahead</a>.
    355. 

  355. </li>
    356. 

  356. </ul>
    357. 

  357. 

  358. <h3>Working with Debugger Tracing</h3>
    359. 

  359. <p>
    360. 

  360. When you generate parsers with the options DEBUG_PARSER or DEBUG_LOOKAHEAD, these
    361. 

  361. parsers produce a trace of their activity which is printed to the user console.
    362. 

  362. You can insert calls to the following methods to control this tracing activity:
    363. 

  363. </p>
    364. 

  364. <ul>
    365. 

  365. <li>
    366. 

  366. <strong>void TheParser.enable_tracing()</strong>
    367. 

  367. </li>
    368. 

  368. <li>
    369. 

  369. <strong>void TheParser.disable_tracing()</strong>
    370. 

  370. </li>
    371. 

  371. </ul>
    372. 

  372. <p>
    373. 

  373. For convenience, these methods are available even when you build parsers without
    374. 

  374. the debug options.  In this case, these methods are no-ops.  Hence you can
    375. 

  375. permanently leave these methods in your code and they automatically kick in when
    376. 

  376. you use the debug options.
    377. 

  377. </p>
    378. 

  378. 

  379. <h3>Customizing Error Messages</h3>
    380. 

  380. <p>
    381. 

  381. To help the user in customizing error messages generated by the parser and lexer, the
    382. 

  382. user is offered the facilities described in this section.  In the case of the
    383. 

  383. parser, these facilities are only available if the option ERROR_REPORTING is
    384. 

  384. true, while in the case of the lexer, these facilities are always available.
    385. 

  385. </p>
    386. 

  386. <p>
    387. 

  387. The parser contains the following method definition:
    388. 

  388. </p>
    389. 

  389. <ul>
    390. 

  390. <li>
    391. 

  391. <strong>protected void token_error() { ... }</strong>
    392. 

  392. </li>
    393. 

  393. </ul>
    394. 

  394. To customize error reporting by the parser, the parser class must be subclassed
    395. 

  395. and this method redefined in the subclass.  To help with creating your
    396. 

  396. error reporting scheme, the following variables are available:
    397. 

  397. <ul>
    398. 

  398. <li>
    399. 

  399. <strong>protected int error_line, error_column;</strong>
    400. 

  400. <br />
    401. 

  401. The line and column where the error was detected.
    402. 

  402. </li>
    403. 

  403. <li>
    404. 

  404. <strong>protected String error_string;</strong>
    405. 

  405. <br />
    406. 

  406. The image of the offending token or set of tokens.  When a lookahead of more
    407. 

  407. than 1 is used, more than one token may be present here.
    408. 

  408. </li>
    409. 

  409. <li>
    410. 

  410. <strong>protected String[] expected_tokens;</strong>
    411. 

  411. <br />
    412. 

  412. An array of images of legitimate token sequences.  Here again, each legitimate
    413. 

  413. token sequence may be more than just one token when a lookahead of more than
    414. 

  414. 1 is used.
    415. 

  415. </li>
    416. 

  416. </ul>
    417. 

  417. <p>
    418. 

  418. The lexer contains the following method definition:
    419. 

  419. </p>
    420. 

  420. <ul>
    421. 

  421. <li>
    422. 

  422. <strong>protected void LexicalError() { ... }</strong>
    423. 

  423. </li>
    424. 

  424. </ul>
    425. 

  425. <p>
    426. 

  426. To customize error reporting by the lexer, the lexer class must be subclassed
    427. 

  427. and this method redefined in the subclass.  To help with creating your
    428. 

  428. error reporting scheme, the following variables are available:
    429. 

  429. </p>
    430. 

  430. <ul>
    431. 

  431. <li>
    432. 

  432. <strong>protected int error_line, error_column;</strong>
    433. 

  433. <br />
    434. 

  434. The line and column where the error was detected.
    435. 

  435. </li>
    436. 

  436. <li>
    437. 

  437. <strong>protected String error_after;</strong>
    438. 

  438. <br />
    439. 

  439. The partial string that has been read since the last successful token
    440. 

  440. match was performed.
    441. 

  441. </li>
    442. 

  442. <li>
    443. 

  443. <strong>protected char curChar;</strong>
    444. 

  444. <br />
    445. 

  445. The offending character.
    446. 

  446. </li>
    447. 

  447. </ul>
    448. 

  448. 

  449. <hr />
    450. 

  450. 

  451. <h1>JavaCC [tm]: JJTree</h1>
    452. 

  452. 

  453. <p>JJTree has two APIs: it adds some <a href="#jjtree-state">parser
    454. 

  454. methods</a>; and it requires all node objects to implement the <a
    455. 

  455. href="#jjtree-node">Node</a> interface.</p>
    456. 

  456. 

  457. <h2><a name="jjtree-state">JJTree parser methods</a></h2>
    458. 

  458. 

  459. <p>JJTree maintains some state in the parser object itself.  It
    460. 

  460. encapsulates all this state with an object that can be referred to via
    461. 

  461. the <code>jjtree</code> field.</p>
    462. 

  462. 

  463. <p>The parser state implements an open stack where nodes are held
    464. 

  464. until they can be added to their parent node.  The <code>jjtree</code>
    465. 

  465. state object provides methods for you to manipulate the contents of
    466. 

  466. the stack in your actions if the basic JJTree mechanisms are not
    467. 

  467. sufficient.
    468. 

  468. </p>
    469. 

  469. 

  470. <dl>
    471. 

  471.       <dt><strong><code>void reset()</code></strong></dt>
    472. 

  472. 

  473.       <dd>Call this to reinitialize the node stack.  All nodes
    474. 

  474.       currently on the stack are thrown away.  Don't call this from
    475. 

  475.       within a node scope, or terrible things will surely happen.</dd>
    476. 

  476. 

  477.       <dt><strong><code>Node rootNode();</code></strong></dt>
    478. 

  478. 

  479.       <dd>Returns the root node of the AST.  Since JJTree operates
    480. 

  480.       bottom-up, the root node is only defined after the parse has
    481. 

  481.       finished.</dd>
    482. 

  482. 

  483.       <dt><strong><code>boolean nodeCreated();</code></strong></dt>
    484. 

  484. 

  485.       <dd>Determines whether the current node was actually closed and
    486. 

  486.       pushed.  Call this in the final action within a conditional node
    487. 

  487.       scope.</dd>
    488. 

  488. 

  489.       <dt><strong><code>int arity();</code></strong></dt>
    490. 

  490. 

  491.       <dd>Returns the number of nodes currently pushed on the node
    492. 

  492.       stack in the current node scope.</dd>
    493. 

  493. 

  494.       <dt><strong><code>void pushNode(Node n);</code></strong></dt>
    495. 

  495. 

  496.       <dd>Pushes a node on to the stack.</dd>
    497. 

  497. 

  498.       <dt><strong><code>Node popNode();</code></strong></dt>
    499. 

  499. 

  500.       <dd>Returns the node on the top of the stack, and removes it from
    501. 

  501.       the stack.</dd>
    502. 

  502. 

  503.       <dt><strong><code>Node peekNode();</code></strong></dt>
    504. 

  504. 

  505.       <dd>Returns the node currently on the top of the stack.</dd>
    506. 

  506.     </dl>
    507. 

  507. 

  508. <hr />
    509. 

  509. 

  510. <h2>The <strong><code><a name="jjtree-node">Node</a></code></strong> interface</h2>
    511. 

  511. 

  512. <p>
    513. 

  513. All AST nodes must implement this interface.  It provides basic
    514. 

  514. machinery for constructing the parent and child relationships between
    515. 

  515. nodes.
    516. 

  516. </p>
    517. 

  517. 

  518. <dl>
    519. 

  519.       <dt><strong><code>public void jjtOpen();</code></strong></dt>
    520. 

  520. 

  521.       <dd>This method is called after the node has been made the
    522. 

  522.       current node.  It indicates that child nodes can now be added to
    523. 

  523.       it.</dd>
    524. 

  524. 

  525.       <dt><strong><code>public void jjtClose();</code></strong></dt>
    526. 

  526. 

  527.       <dd>This method is called after all the child nodes have been
    528. 

  528. 	added.</dd>
    529. 

  529. 

  530.       <dt><strong><code>public void jjtSetParent(Node n);</code><br /><code>public Node jjtGetParent();</code></strong></dt>
    531. 

  531. 

  532.       <dd>This pair of methods is used to inform the node of its
    533. 

  533.       parent.</dd>
    534. 

  534. 

  535.       <dt><strong><code>public void jjtAddChild(Node n, int i);</code></strong></dt>
    536. 

  536. 

  537.       <dd>This method tells the node to add its argument to the node's
    538. 

  538. 	list of children.</dd>
    539. 

  539. 

  540.       <dt><strong><code>public Node jjtGetChild(int i);</code></strong></dt>
    541. 

  541. 

  542.       <dd>This method returns a child node.  The children are numbered
    543. 

  543. 	 from zero, left to right.</dd>
    544. 

  544. 

  545.       <dt><strong><code>int jjtGetNumChildren();</code></strong></dt>
    546. 

  546. 

  547.       <dd>Return the number of children the node has.</dd>
    548. 

  548. 

  549. </dl>
    550. 

  550. 

  551. </body>
    552. 

  552. </html>
    553. 

  553.