280 lines
10 KiB
Plaintext
Executable File
280 lines
10 KiB
Plaintext
Executable File
# jay skeleton
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# character in column 1 determines outcome...
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# # is a comment
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# . is copied
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# t is copied as //t if -t is set
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# other lines are interpreted to call jay procedures
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.// created by jay 0.7 (c) 1998 Axel.Schreiner@informatik.uni-osnabrueck.de
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.
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prolog ## %{ ... %} prior to the first %%
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.// %token constants
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. //{ //ergaenzt PL 23.01.01 wieder entfernt 21.12.01
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tokens public static final int
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.
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. /** thrown for irrecoverable syntax errors and stack overflow.
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. */
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. public static class yyException extends java.lang.Exception {
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. public Token token;
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. public yyException (String message, Token token) {
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. super(message);
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. this.token=token;
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. }
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. }
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.
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. /** must be implemented by a scanner object to supply input to the parser.
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. */
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. public interface yyInput {
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. /** move on to next token.
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. @return false if positioned beyond tokens.
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. @throws IOException on input error.
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. */
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. boolean advance () throws java.io.IOException;
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. /** classifies current token.
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. Should not be called if advance() returned false.
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. @return current %token or single character.
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. */
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. int token ();
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. /** associated with current token.
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. Should not be called if advance() returned false.
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. @return value for token().
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. */
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. Object value ();
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. }
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.
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. /** simplified error message.
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. @see <a href="#yyerror(java.lang.String, java.lang.String[])">yyerror</a>
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. */
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. public void yyerror (String message) {
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. yyerror(message, null);
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. }
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.
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. /** (syntax) error message.
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. Can be overwritten to control message format.
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. @param message text to be displayed.
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. @param expected vector of acceptable tokens, if available.
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. */
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. public String yyerror (String message, String[] expected) {
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. if (expected != null && expected.length > 0) {
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. System.err.print(message+", expecting");
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. message+=", expecting";
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. for (int n = 0; n < expected.length; ++ n){
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. System.err.print(" "+expected[n]);
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. message+=" "+expected[n];}
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. System.err.println();
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. return message;
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. } else{
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. System.err.println(message);
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. return message;}
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. }
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.
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. /** debugging support, requires the package jay.yydebug.
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. Set to null to suppress debugging messages.
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. */
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t protected jay.yydebug.yyDebug yydebug;
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.
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debug ## tables for debugging support
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.
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. /** index-checked interface to yyName[].
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. @param token single character or %token value.
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. @return token name or [illegal] or [unknown].
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. */
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t public static final String yyname (int token) {
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t if (token < 0 || token > yyName.length) return "[illegal]";
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t String name;
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t if ((name = yyName[token]) != null) return name;
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t return "[unknown]";
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t }
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.
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. /** computes list of expected tokens on error by tracing the tables.
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. @param state for which to compute the list.
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. @return list of token names.
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. */
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. protected String[] yyExpecting (int state) {
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. // yyCheck durch yyCheckInit.yyCheck; ersetzt PL 25.1.01
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. int token, n, len = 0;
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. boolean[] ok = new boolean[yyName.length];
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.
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. if ((n = yySindex[state]) != 0)
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. for (token = n < 0 ? -n : 0;
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. token < yyName.length && n+token < yyTable.length; ++ token)
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. if (yyCheckInit.yyCheck[n+token] == token && !ok[token] && yyName[token] != null) {
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. ++ len;
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. ok[token] = true;
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. }
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. if ((n = yyRindex[state]) != 0)
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. for (token = n < 0 ? -n : 0;
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. token < yyName.length && n+token < yyTable.length; ++ token)
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. if (yyCheckInit.yyCheck[n+token] == token && !ok[token] && yyName[token] != null) {
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. ++ len;
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. ok[token] = true;
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. }
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.
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. String result[] = new String[len];
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. for (n = token = 0; n < len; ++ token)
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. if (ok[token]) result[n++] = yyName[token];
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. return result;
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. }
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.
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. /** the generated parser, with debugging messages.
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. Maintains a state and a value stack, currently with fixed maximum size.
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. @param yyLex scanner.
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. @param yydebug debug message writer implementing yyDebug, or null.
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. @return result of the last reduction, if any.
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. @throws yyException on irrecoverable parse error.
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. */
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. public Object yyparse (yyInput yyLex, Object yydebug)
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. throws java.io.IOException, yyException {
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t this.yydebug = (jay.yydebug.yyDebug)yydebug;
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. return yyparse(yyLex);
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. }
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.
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. /** initial size and increment of the state/value stack [default 256].
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. This is not final so that it can be overwritten outside of invocations
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. of yyparse().
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. */
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. protected int yyMax;
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.
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. /** executed at the beginning of a reduce action.
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. Used as $$ = yyDefault($1), prior to the user-specified action, if any.
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. Can be overwritten to provide deep copy, etc.
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. @param first value for $1, or null.
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. @return first.
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. */
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. protected Object yyDefault (Object first) {
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. return first;
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. }
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.
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. /** the generated parser.
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. Maintains a state and a value stack, currently with fixed maximum size.
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. @param yyLex scanner.
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. @return result of the last reduction, if any.
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. @throws yyException on irrecoverable parse error.
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. */
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. public Object yyparse (yyInput yyLex)
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. throws java.io.IOException, yyException {
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. // yyCheck durch yyCheckInit.yyCheck; ersetzt PL 23.1.01
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. yyCheckInit.yyCheckInit(); // initial yyCheck eingefuegt PL 25.1.01
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. if (yyMax <= 0) yyMax = 256; // initial size
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. int yyState = 0, yyStates[] = new int[yyMax]; // state stack
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. Object yyVal = null, yyVals[] = new Object[yyMax]; // value stack
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. int yyToken = -1; // current input
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. int yyErrorFlag = 0; // #tks to shift
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. Scanner yyScanner = (Scanner)yyLex;
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. String yyErrorString = "irrecoverable syntax error";
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.
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local ## %{ ... %} after the first %%
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. yyLoop: for (int yyTop = 0;; ++ yyTop) {
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. if (yyTop >= yyStates.length) { // dynamically increase
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. int[] i = new int[yyStates.length+yyMax];
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. System.arraycopy(yyStates, 0, i, 0, yyStates.length);
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. yyStates = i;
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. Object[] o = new Object[yyVals.length+yyMax];
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. System.arraycopy(yyVals, 0, o, 0, yyVals.length);
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. yyVals = o;
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. }
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. yyStates[yyTop] = yyState;
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. yyVals[yyTop] = yyVal;
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t if (yydebug != null) yydebug.push(yyState, yyVal);
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.
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. yyDiscarded: for (;;) { // discarding a token does not change stack
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. int yyN;
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. if ((yyN = yyDefRed[yyState]) == 0) { // else [default] reduce (yyN)
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. if (yyToken < 0) {
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. yyToken = yyLex.advance() ? yyLex.token() : 0;
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t if (yydebug != null)
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t yydebug.lex(yyState, yyToken, yyname(yyToken), yyLex.value());
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. }
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. if ((yyN = yySindex[yyState]) != 0 && (yyN += yyToken) >= 0
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. && yyN < yyTable.length && yyCheckInit.yyCheck[yyN] == yyToken) {
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t if (yydebug != null)
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t yydebug.shift(yyState, yyTable[yyN], yyErrorFlag-1);
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. yyState = yyTable[yyN]; // shift to yyN
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. yyVal = yyLex.value();
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. yyToken = -1;
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. if (yyErrorFlag > 0) -- yyErrorFlag;
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. continue yyLoop;
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. }
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. if ((yyN = yyRindex[yyState]) != 0 && (yyN += yyToken) >= 0
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. && yyN < yyTable.length && yyCheckInit.yyCheck[yyN] == yyToken)
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. yyN = yyTable[yyN]; // reduce (yyN)
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. else
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. switch (yyErrorFlag) {
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.
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. case 0:
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. yyErrorString=yyerror("syntax error", yyExpecting(yyState));
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t if (yydebug != null) yydebug.error("syntax error");
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.
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. case 1: case 2:
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. yyErrorFlag = 3;
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. do {
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. if ((yyN = yySindex[yyStates[yyTop]]) != 0
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. && (yyN += yyErrorCode) >= 0 && yyN < yyTable.length
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. && yyCheckInit.yyCheck[yyN] == yyErrorCode) {
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t if (yydebug != null)
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t yydebug.shift(yyStates[yyTop], yyTable[yyN], 3);
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. yyState = yyTable[yyN];
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. yyVal = yyLex.value();
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. continue yyLoop;
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. }
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t if (yydebug != null) yydebug.pop(yyStates[yyTop]);
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. } while (-- yyTop >= 0);
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t if (yydebug != null) yydebug.reject();
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. throw new yyException(yyErrorString, yyScanner.token);
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.
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. case 3:
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. if (yyToken == 0) {
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t if (yydebug != null) yydebug.reject();
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. throw new yyException(yyErrorString+"at end-of-file", yyScanner.token);
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. }
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t if (yydebug != null)
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t yydebug.discard(yyState, yyToken, yyname(yyToken),
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t yyLex.value());
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. yyToken = -1;
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. continue yyDiscarded; // leave stack alone
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. }
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. }
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. int yyV = yyTop + 1-yyLen[yyN];
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t if (yydebug != null)
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t yydebug.reduce(yyState, yyStates[yyV-1], yyN, yyRule[yyN], yyLen[yyN]);
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. yyVal = yyDefault(yyV > yyTop ? null : yyVals[yyV]);
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. switch (yyN) {
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actions ## code from the actions within the grammar
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. }
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. yyTop -= yyLen[yyN];
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. yyState = yyStates[yyTop];
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. int yyM = yyLhs[yyN];
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. if (yyState == 0 && yyM == 0) {
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t if (yydebug != null) yydebug.shift(0, yyFinal);
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. yyState = yyFinal;
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. if (yyToken < 0) {
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. yyToken = yyLex.advance() ? yyLex.token() : 0;
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t if (yydebug != null)
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t yydebug.lex(yyState, yyToken,yyname(yyToken), yyLex.value());
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. }
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. if (yyToken == 0) {
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t if (yydebug != null) yydebug.accept(yyVal);
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. return yyVal;
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. }
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. continue yyLoop;
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. }
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. if ((yyN = yyGindex[yyM]) != 0 && (yyN += yyState) >= 0
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. && yyN < yyTable.length && yyCheckInit.yyCheck[yyN] == yyState)
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. yyState = yyTable[yyN];
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. else
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. yyState = yyDgoto[yyM];
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t if (yydebug != null) yydebug.shift(yyStates[yyTop], yyState);
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. continue yyLoop;
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. }
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. }
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. }
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.
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tables ## tables for rules, default reduction, and action calls
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.
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epilog ## text following second %%
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