269 lines
9.4 KiB
Plaintext
269 lines
9.4 KiB
Plaintext
# 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, YYRules.getRule[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 %%
|