//
// Parse input allowing up to max_error_count Error token recoveries.
// When max_error_count is 0, no Error token recoveries occur.
// When max_error is > 0, it limits the number of Error token recoveries.
// When max_error is < 0, the number of error token recoveries is unlimited.
// Also, such recoveries only require one token to be parsed beyond the
// recovery point.
// (normally two tokens beyond the recovery point must be parsed)
// Thus, a negative max_error_count should be used when error productions
// are used to
// skip tokens.
//
public Object parse(int max_error_count) throws BadParseException {
state = new ParserState(START_STATE, tokStream);
skipTokens = max_error_count < 0;
state.pendingCommits = new LinkedList();
backtrackRequested = false;
state.trialActionCount = 0;
// Next "start" token
state.repair_token = 0;
int start_token_index = tokStream.peek();
int start_action_index = 0;
// Last commit point
int[] temp_stack = new int[1];
temp_stack[0] = START_STATE;
state.reallocateOtherStacks(start_token_index);
int initial_error_token = backtrackParse(state.repair_token);
for (int error_token = initial_error_token, count = 0;
error_token != 0;
error_token = backtrackParse(state.repair_token), count++) {
if (count == max_error_count) throw new BadParseException(initial_error_token);
state.actionCount = start_action_index;
tokStream.reset(start_token_index);
state.stateStackTop = temp_stack.length - 1;
System.arraycopy(temp_stack, 0, state.stateStack, 0, temp_stack.length);
state.reallocateOtherStacks(start_token_index);
backtrackParseUpToError(state.repair_token, error_token);
for (state.stateStackTop = findRecoveryStateIndex(state.stateStackTop);
state.stateStackTop >= 0;
state.stateStackTop = findRecoveryStateIndex(state.stateStackTop - 1)) {
int recovery_token = state.tokens.get(state.locationStack[state.stateStackTop] - 1);
state.repair_token =
errorRepair(
(recovery_token >= start_token_index ? recovery_token : error_token), error_token);
if (state.repair_token != 0) break;
}
if (state.stateStackTop < 0) throw new BadParseException(initial_error_token);
temp_stack = new int[state.stateStackTop + 1];
System.arraycopy(state.stateStack, 0, temp_stack, 0, temp_stack.length);
start_action_index = state.actionCount;
start_token_index = tokStream.peek();
}
if (state.repair_token != 0) state.tokens.add(state.repair_token);
int t;
for (t = start_token_index; tokStream.getKind(t) != EOFT_SYMBOL; t = tokStream.getNext(t))
state.tokens.add(t);
state.tokens.add(t);
return null;
}
private int errorRepair(int recovery_token, int error_token) {
int temp_stack[] = new int[state.stateStackTop + 1];
System.arraycopy(state.stateStack, 0, temp_stack, 0, temp_stack.length);
for (;
tokStream.getKind(recovery_token) != EOFT_SYMBOL;
recovery_token = tokStream.getNext(recovery_token)) {
System.out.println("recovery token: " + tokStream.getKind(recovery_token)); // $NON-NLS-1$
tokStream.reset(recovery_token);
if (repairable(error_token)) break;
state.stateStackTop = temp_stack.length - 1;
System.arraycopy(temp_stack, 0, state.stateStack, 0, temp_stack.length);
}
if (tokStream.getKind(recovery_token) == EOFT_SYMBOL) {
tokStream.reset(recovery_token);
if (!repairable(error_token)) {
state.stateStackTop = temp_stack.length - 1;
System.arraycopy(temp_stack, 0, state.stateStack, 0, temp_stack.length);
return 0;
}
}
state.stateStackTop = temp_stack.length - 1;
System.arraycopy(temp_stack, 0, state.stateStack, 0, temp_stack.length);
undoActions(state.undoStack[state.stateStackTop]);
tokStream.reset(recovery_token);
state.tokens.reset(state.locationStack[state.stateStackTop] - 1);
state.actionCount = state.actionStack[state.stateStackTop];
state.trialActionCount = state.undoStack[state.stateStackTop];
return tokStream.makeErrorToken(
state.tokens.get(state.locationStack[state.stateStackTop] - 1),
tokStream.getPrevious(recovery_token),
error_token,
ERROR_SYMBOL);
}