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 . /** simplified error message.
15 . @see <a href="#yyerror(java.lang.String, java.lang.String[])">yyerror</a>
17 . public void yyerror (string message) {
18 . yyerror(message, null);
21 . /** (syntax) error message.
22 . Can be overwritten to control message format.
23 . @param message text to be displayed.
24 . @param expected vector of acceptable tokens, if available.
26 . public void yyerror (string message, string[] expected) {
27 . if ((expected != null) && (expected.Length > 0)) {
28 . System.Console.Write (message+", expecting");
29 . for (int n = 0; n < expected.Length; ++ n)
30 . System.Console.Write (" "+expected[n]);
31 . System.Console.WriteLine ();
33 . System.Console.WriteLine (message);
36 . /** debugging support, requires the package jay.yydebug.
37 . Set to null to suppress debugging messages.
39 t protected yydebug.yyDebug debug;
41 debug ## tables for debugging support
43 . /** index-checked interface to yyNames[].
44 . @param token single character or %token value.
45 . @return token name or [illegal] or [unknown].
47 t public static string yyname (int token) {
48 t if ((token < 0) || (token > yyNames.Length)) return "[illegal]";
50 t if ((name = yyNames[token]) != null) return name;
54 . /** computes list of expected tokens on error by tracing the tables.
55 . @param state for which to compute the list.
56 . @return list of token names.
58 . protected string[] yyExpecting (int state) {
59 . int token, n, len = 0;
60 . bool[] ok = new bool[yyNames.Length];
62 . if ((n = yySindex[state]) != 0)
63 . for (token = n < 0 ? -n : 0;
64 . (token < yyNames.Length) && (n+token < yyTable.Length); ++ token)
65 . if (yyCheck[n+token] == token && !ok[token] && yyNames[token] != null) {
69 . if ((n = yyRindex[state]) != 0)
70 . for (token = n < 0 ? -n : 0;
71 . (token < yyNames.Length) && (n+token < yyTable.Length); ++ token)
72 . if (yyCheck[n+token] == token && !ok[token] && yyNames[token] != null) {
77 . string [] result = new string[len];
78 . for (n = token = 0; n < len; ++ token)
79 . if (ok[token]) result[n++] = yyNames[token];
83 . /** the generated parser, with debugging messages.
84 . Maintains a state and a value stack, currently with fixed maximum size.
85 . @param yyLex scanner.
86 . @param yydebug debug message writer implementing yyDebug, or null.
87 . @return result of the last reduction, if any.
88 . @throws yyException on irrecoverable parse error.
90 . public Object yyparse (yyParser.yyInput yyLex, Object yyd)
92 t this.debug = (yydebug.yyDebug)yyd;
93 . return yyparse(yyLex);
96 . /** initial size and increment of the state/value stack [default 256].
97 . This is not final so that it can be overwritten outside of invocations
100 . protected int yyMax;
102 . /** executed at the beginning of a reduce action.
103 . Used as $$ = yyDefault($1), prior to the user-specified action, if any.
104 . Can be overwritten to provide deep copy, etc.
105 . @param first value for $1, or null.
108 . protected Object yyDefault (Object first) {
112 . /** the generated parser.
113 . Maintains a state and a value stack, currently with fixed maximum size.
114 . @param yyLex scanner.
115 . @return result of the last reduction, if any.
116 . @throws yyException on irrecoverable parse error.
118 . public Object yyparse (yyParser.yyInput yyLex)
120 . if (yyMax <= 0) yyMax = 256; // initial size
121 . int yyState = 0; // state stack ptr
122 . int [] yyStates = new int[yyMax]; // state stack
123 . Object yyVal = null; // value stack ptr
124 . Object [] yyVals = new Object[yyMax]; // value stack
125 . int yyToken = -1; // current input
126 . int yyErrorFlag = 0; // #tks to shift
128 local ## %{ ... %} after the first %%
135 . for (;; ++ yyTop) {
136 . if (yyTop >= yyStates.Length) { // dynamically increase
137 . int[] i = new int[yyStates.Length+yyMax];
138 . yyStates.CopyTo (i, 0);
140 . Object[] o = new Object[yyVals.Length+yyMax];
141 . yyVals.CopyTo (o, 0);
144 . yyStates[yyTop] = yyState;
145 . yyVals[yyTop] = yyVal;
146 t if (debug != null) debug.push(yyState, yyVal);
148 . yyDiscarded: for (;;) { // discarding a token does not change stack
150 . if ((yyN = yyDefRed[yyState]) == 0) { // else [default] reduce (yyN)
152 . yyToken = yyLex.advance() ? yyLex.token() : 0;
155 t debug.lex(yyState, yyToken, yyname(yyToken), yyLex.value());
157 . if ((yyN = yySindex[yyState]) != 0 && ((yyN += yyToken) >= 0)
158 . && (yyN < yyTable.Length) && (yyCheck[yyN] == yyToken)) {
160 t debug.shift(yyState, yyTable[yyN], yyErrorFlag-1);
161 . yyState = yyTable[yyN]; // shift to yyN
162 . yyVal = yyLex.value();
164 . if (yyErrorFlag > 0) -- yyErrorFlag;
167 . if ((yyN = yyRindex[yyState]) != 0 && (yyN += yyToken) >= 0
168 . && yyN < yyTable.Length && yyCheck[yyN] == yyToken)
169 . yyN = yyTable[yyN]; // reduce (yyN)
171 . switch (yyErrorFlag) {
174 . yyerror("syntax error", yyExpecting(yyState));
175 t if (debug != null) debug.error("syntax error");
180 . if ((yyN = yySindex[yyStates[yyTop]]) != 0
181 . && (yyN += Token.yyErrorCode) >= 0 && yyN < yyTable.Length
182 . && yyCheck[yyN] == Token.yyErrorCode) {
184 t debug.shift(yyStates[yyTop], yyTable[yyN], 3);
185 . yyState = yyTable[yyN];
186 . yyVal = yyLex.value();
189 t if (debug != null) debug.pop(yyStates[yyTop]);
190 . } while (-- yyTop >= 0);
191 t if (debug != null) debug.reject();
192 . throw new yyParser.yyException("irrecoverable syntax error");
195 . if (yyToken == 0) {
196 t if (debug != null) debug.reject();
197 . throw new yyParser.yyException("irrecoverable syntax error at end-of-file");
200 t debug.discard(yyState, yyToken, yyname(yyToken),
203 . goto yyDiscarded; // leave stack alone
206 . int yyV = yyTop + 1-yyLen[yyN];
208 t debug.reduce(yyState, yyStates[yyV-1], yyN, yyRule[yyN], yyLen[yyN]);
209 . yyVal = yyDefault(yyV > yyTop ? null : yyVals[yyV]);
212 actions ## code from the actions within the grammar
215 . yyTop -= yyLen[yyN];
216 . yyState = yyStates[yyTop];
217 . int yyM = yyLhs[yyN];
218 . if (yyState == 0 && yyM == 0) {
219 t if (debug != null) debug.shift(0, yyFinal);
222 . yyToken = yyLex.advance() ? yyLex.token() : 0;
225 t debug.lex(yyState, yyToken,yyname(yyToken), yyLex.value());
227 . if (yyToken == 0) {
228 t if (debug != null) debug.accept(yyVal);
233 . if (((yyN = yyGindex[yyM]) != 0) && ((yyN += yyState) >= 0)
234 . && (yyN < yyTable.Length) && (yyCheck[yyN] == yyState))
235 . yyState = yyTable[yyN];
237 . yyState = yyDgoto[yyM];
238 t if (debug != null) debug.shift(yyStates[yyTop], yyState);
244 tables ## tables for rules, default reduction, and action calls
246 epilog ## text following second %%
249 . public interface yyDebug {
250 . void push (int state, Object value);
251 . void lex (int state, int token, string name, Object value);
252 . void shift (int from, int to, int errorFlag);
253 . void pop (int state);
254 . void discard (int state, int token, string name, Object value);
255 . void reduce (int from, int to, int rule, string text, int len);
256 . void shift (int from, int to);
257 . void accept (Object value);
258 . void error (string message);
262 . class yyDebugSimple : yyDebug {
263 . void println (string s){
264 . Console.WriteLine (s);
267 . public void push (int state, Object value) {
268 . println ("push\tstate "+state+"\tvalue "+value);
271 . public void lex (int state, int token, string name, Object value) {
272 . println("lex\tstate "+state+"\treading "+name+"\tvalue "+value);
275 . public void shift (int from, int to, int errorFlag) {
276 . switch (errorFlag) {
277 . default: // normally
278 . println("shift\tfrom state "+from+" to "+to);
280 . case 0: case 1: case 2: // in error recovery
281 . println("shift\tfrom state "+from+" to "+to
282 . +"\t"+errorFlag+" left to recover");
284 . case 3: // normally
285 . println("shift\tfrom state "+from+" to "+to+"\ton error");
290 . public void pop (int state) {
291 . println("pop\tstate "+state+"\ton error");
294 . public void discard (int state, int token, string name, Object value) {
295 . println("discard\tstate "+state+"\ttoken "+name+"\tvalue "+value);
298 . public void reduce (int from, int to, int rule, string text, int len) {
299 . println("reduce\tstate "+from+"\tuncover "+to
300 . +"\trule ("+rule+") "+text);
303 . public void shift (int from, int to) {
304 . println("goto\tfrom state "+from+" to "+to);
307 . public void accept (Object value) {
308 . println("accept\tvalue "+value);
311 . public void error (string message) {
312 . println("error\t"+message);
315 . public void reject () {
323 tokens public const int
325 . namespace yyParser {
327 . /** thrown for irrecoverable syntax errors and stack overflow.
329 . public class yyException : System.Exception {
330 . public yyException (string message) : base (message) {
334 . /** must be implemented by a scanner object to supply input to the parser.
336 . public interface yyInput {
337 . /** move on to next token.
338 . @return false if positioned beyond tokens.
339 . @throws IOException on input error.
341 . bool advance (); // throws java.io.IOException;
342 . /** classifies current token.
343 . Should not be called if advance() returned false.
344 . @return current %token or single character.
347 . /** associated with current token.
348 . Should not be called if advance() returned false.
349 . @return value for token().
354 .} // close outermost namespace, that MUST HAVE BEEN opened in the prolog