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