3 # character in column 1 determines outcome...
6 # t is copied as //t if -t is set
7 # other lines are interpreted to call jay procedures
9 .// created by jay 0.7 (c) 1998 Axel.Schreiner@informatik.uni-osnabrueck.de
11 prolog ## %{ ... %} prior to the first %%
14 . /** error output stream.
15 . It should be changeable.
17 . public System.IO.TextWriter ErrorOutput = System.Console.Out;
19 . /** simplified error message.
20 . @see <a href="#yyerror(java.lang.String, java.lang.String[])">yyerror</a>
22 . public void yyerror (string message) {
23 . yyerror(message, null);
27 . public int eof_token;
29 . /** (syntax) error message.
30 . Can be overwritten to control message format.
31 . @param message text to be displayed.
32 . @param expected vector of acceptable tokens, if available.
34 . public void yyerror (string message, string[] expected) {
35 . if ((yacc_verbose_flag > 0) && (expected != null) && (expected.Length > 0)) {
36 . ErrorOutput.Write (message+", expecting");
37 . for (int n = 0; n < expected.Length; ++ n)
38 . ErrorOutput.Write (" "+expected[n]);
39 . ErrorOutput.WriteLine ();
41 . ErrorOutput.WriteLine (message);
44 . /** debugging support, requires the package jay.yydebug.
45 . Set to null to suppress debugging messages.
47 t internal yydebug.yyDebug debug;
49 debug ## tables for debugging support
51 . /** index-checked interface to yyNames[].
52 . @param token single character or %token value.
53 . @return token name or [illegal] or [unknown].
55 t public static string yyname (int token) {
56 t if ((token < 0) || (token > yyNames.Length)) return "[illegal]";
58 t if ((name = yyNames[token]) != null) return name;
62 . /** computes list of expected tokens on error by tracing the tables.
63 . @param state for which to compute the list.
64 . @return list of token names.
66 . protected string[] yyExpecting (int state) {
67 . int token, n, len = 0;
68 . bool[] ok = new bool[yyNames.Length];
70 . if ((n = yySindex[state]) != 0)
71 . for (token = n < 0 ? -n : 0;
72 . (token < yyNames.Length) && (n+token < yyTable.Length); ++ token)
73 . if (yyCheck[n+token] == token && !ok[token] && yyNames[token] != null) {
77 . if ((n = yyRindex[state]) != 0)
78 . for (token = n < 0 ? -n : 0;
79 . (token < yyNames.Length) && (n+token < yyTable.Length); ++ token)
80 . if (yyCheck[n+token] == token && !ok[token] && yyNames[token] != null) {
85 . string [] result = new string[len];
86 . for (n = token = 0; n < len; ++ token)
87 . if (ok[token]) result[n++] = yyNames[token];
91 . /** the generated parser, with debugging messages.
92 . Maintains a state and a value stack, currently with fixed maximum size.
93 . @param yyLex scanner.
94 . @param yydebug debug message writer implementing yyDebug, or null.
95 . @return result of the last reduction, if any.
96 . @throws yyException on irrecoverable parse error.
98 . internal Object yyparse (yyParser.yyInput yyLex, Object yyd)
100 t this.debug = (yydebug.yyDebug)yyd;
101 . return yyparse(yyLex);
104 . /** initial size and increment of the state/value stack [default 256].
105 . This is not final so that it can be overwritten outside of invocations
108 . protected int yyMax;
110 . /** executed at the beginning of a reduce action.
111 . Used as $$ = yyDefault($1), prior to the user-specified action, if any.
112 . Can be overwritten to provide deep copy, etc.
113 . @param first value for $1, or null.
116 . protected Object yyDefault (Object first) {
120 . /** the generated parser.
121 . Maintains a state and a value stack, currently with fixed maximum size.
122 . @param yyLex scanner.
123 . @return result of the last reduction, if any.
124 . @throws yyException on irrecoverable parse error.
126 . internal Object yyparse (yyParser.yyInput yyLex)
128 . if (yyMax <= 0) yyMax = 256; // initial size
129 . int yyState = 0; // state stack ptr
130 . int [] yyStates = new int[yyMax]; // state stack
131 . Object yyVal = null; // value stack ptr
132 . Object [] yyVals = new Object[yyMax]; // value stack
133 . int yyToken = -1; // current input
134 . int yyErrorFlag = 0; // #tks to shift
136 local ## %{ ... %} after the first %%
138 . /*yyLoop:*/ for (int yyTop = 0;; ++ yyTop) {
139 . if (yyTop >= yyStates.Length) { // dynamically increase
140 . int[] i = new int[yyStates.Length+yyMax];
141 . yyStates.CopyTo (i, 0);
143 . Object[] o = new Object[yyVals.Length+yyMax];
144 . yyVals.CopyTo (o, 0);
147 . yyStates[yyTop] = yyState;
148 . yyVals[yyTop] = yyVal;
149 t if (debug != null) debug.push(yyState, yyVal);
151 . /*yyDiscarded:*/ for (;;) { // discarding a token does not change stack
153 . if ((yyN = yyDefRed[yyState]) == 0) { // else [default] reduce (yyN)
155 . yyToken = yyLex.advance() ? yyLex.token() : 0;
158 t debug.lex(yyState, yyToken, yyname(yyToken), yyLex.value());
160 . if ((yyN = yySindex[yyState]) != 0 && ((yyN += yyToken) >= 0)
161 . && (yyN < yyTable.Length) && (yyCheck[yyN] == yyToken)) {
163 t debug.shift(yyState, yyTable[yyN], yyErrorFlag-1);
164 . yyState = yyTable[yyN]; // shift to yyN
165 . yyVal = yyLex.value();
167 . if (yyErrorFlag > 0) -- yyErrorFlag;
168 . goto continue_yyLoop;
170 . if ((yyN = yyRindex[yyState]) != 0 && (yyN += yyToken) >= 0
171 . && yyN < yyTable.Length && yyCheck[yyN] == yyToken)
172 . yyN = yyTable[yyN]; // reduce (yyN)
174 . switch (yyErrorFlag) {
177 . // yyerror(String.Format ("syntax error, got token `{0}'", yyname (yyToken)), yyExpecting(yyState));
178 t if (debug != null) debug.error("syntax error");
179 . if (yyToken == 0 || yyToken == eof_token /* eof */) throw new yyParser.yyUnexpectedEof ();
184 . if ((yyN = yySindex[yyStates[yyTop]]) != 0
185 . && (yyN += Token.yyErrorCode) >= 0 && yyN < yyTable.Length
186 . && yyCheck[yyN] == Token.yyErrorCode) {
188 t debug.shift(yyStates[yyTop], yyTable[yyN], 3);
189 . yyState = yyTable[yyN];
190 . yyVal = yyLex.value();
191 . goto continue_yyLoop;
193 t if (debug != null) debug.pop(yyStates[yyTop]);
194 . } while (-- yyTop >= 0);
195 t if (debug != null) debug.reject();
196 . throw new yyParser.yyException("irrecoverable syntax error");
199 . if (yyToken == 0) {
200 t if (debug != null) debug.reject();
201 . throw new yyParser.yyException("irrecoverable syntax error at end-of-file");
204 t debug.discard(yyState, yyToken, yyname(yyToken),
207 . goto continue_yyDiscarded; // leave stack alone
210 . int yyV = yyTop + 1-yyLen[yyN];
212 t debug.reduce(yyState, yyStates[yyV-1], yyN, YYRules.getRule (yyN), yyLen[yyN]);
213 . yyVal = yyDefault(yyV > yyTop ? null : yyVals[yyV]);
216 actions ## code from the actions within the grammar
219 . yyTop -= yyLen[yyN];
220 . yyState = yyStates[yyTop];
221 . int yyM = yyLhs[yyN];
222 . if (yyState == 0 && yyM == 0) {
223 t if (debug != null) debug.shift(0, yyFinal);
226 . yyToken = yyLex.advance() ? yyLex.token() : 0;
229 t debug.lex(yyState, yyToken,yyname(yyToken), yyLex.value());
231 . if (yyToken == 0) {
232 t if (debug != null) debug.accept(yyVal);
235 . goto continue_yyLoop;
237 . if (((yyN = yyGindex[yyM]) != 0) && ((yyN += yyState) >= 0)
238 . && (yyN < yyTable.Length) && (yyCheck[yyN] == yyState))
239 . yyState = yyTable[yyN];
241 . yyState = yyDgoto[yyM];
242 t if (debug != null) debug.shift(yyStates[yyTop], yyState);
243 . goto continue_yyLoop;
244 . continue_yyDiscarded: continue; // implements the named-loop continue: 'continue yyDiscarded'
246 . continue_yyLoop: continue; // implements the named-loop continue: 'continue yyLoop'
250 tables ## tables for rules, default reduction, and action calls
252 epilog ## text following second %%
255 . internal interface yyDebug {
256 . void push (int state, Object value);
257 . void lex (int state, int token, string name, Object value);
258 . void shift (int from, int to, int errorFlag);
259 . void pop (int state);
260 . void discard (int state, int token, string name, Object value);
261 . void reduce (int from, int to, int rule, string text, int len);
262 . void shift (int from, int to);
263 . void accept (Object value);
264 . void error (string message);
268 . class yyDebugSimple : yyDebug {
269 . void println (string s){
270 . Console.Error.WriteLine (s);
273 . public void push (int state, Object value) {
274 . println ("push\tstate "+state+"\tvalue "+value);
277 . public void lex (int state, int token, string name, Object value) {
278 . println("lex\tstate "+state+"\treading "+name+"\tvalue "+value);
281 . public void shift (int from, int to, int errorFlag) {
282 . switch (errorFlag) {
283 . default: // normally
284 . println("shift\tfrom state "+from+" to "+to);
286 . case 0: case 1: case 2: // in error recovery
287 . println("shift\tfrom state "+from+" to "+to
288 . +"\t"+errorFlag+" left to recover");
290 . case 3: // normally
291 . println("shift\tfrom state "+from+" to "+to+"\ton error");
296 . public void pop (int state) {
297 . println("pop\tstate "+state+"\ton error");
300 . public void discard (int state, int token, string name, Object value) {
301 . println("discard\tstate "+state+"\ttoken "+name+"\tvalue "+value);
304 . public void reduce (int from, int to, int rule, string text, int len) {
305 . println("reduce\tstate "+from+"\tuncover "+to
306 . +"\trule ("+rule+") "+text);
309 . public void shift (int from, int to) {
310 . println("goto\tfrom state "+from+" to "+to);
313 . public void accept (Object value) {
314 . println("accept\tvalue "+value);
317 . public void error (string message) {
318 . println("error\t"+message);
321 . public void reject () {
329 tokens public const int
331 . namespace yyParser {
333 . /** thrown for irrecoverable syntax errors and stack overflow.
335 . internal class yyException : System.Exception {
336 . public yyException (string message) : base (message) {
339 . internal class yyUnexpectedEof : yyException {
340 . public yyUnexpectedEof (string message) : base (message) {
342 . public yyUnexpectedEof () : base ("") {
346 . /** must be implemented by a scanner object to supply input to the parser.
348 . internal interface yyInput {
349 . /** move on to next token.
350 . @return false if positioned beyond tokens.
351 . @throws IOException on input error.
353 . bool advance (); // throws java.io.IOException;
354 . /** classifies current token.
355 . Should not be called if advance() returned false.
356 . @return current %token or single character.
359 . /** associated with current token.
360 . Should not be called if advance() returned false.
361 . @return value for token().
366 .} // close outermost namespace, that MUST HAVE BEEN opened in the prolog