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 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2023 QuestDB
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
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package io.questdb.griffin;

import io.questdb.cairo.ColumnType;
import io.questdb.griffin.model.ExpressionNode;
import io.questdb.std.*;

import static io.questdb.griffin.OperatorExpression.DOT_PRECEDENCE;

public class ExpressionParser {

    private static final int BRANCH_BETWEEN_END = 14;
    private static final int BRANCH_BETWEEN_START = 13;
    private static final int BRANCH_CASE_CONTROL = 10;
    private static final int BRANCH_CASE_START = 9;
    private static final int BRANCH_CAST_AS = 11;
    private static final int BRANCH_COMMA = 1;
    private static final int BRANCH_CONSTANT = 4;
    private static final int BRANCH_DOT = 12;
    private static final int BRANCH_DOT_DEREFERENCE = 17;
    private static final int BRANCH_GEOHASH = 18;
    private static final int BRANCH_LAMBDA = 7;
    private static final int BRANCH_LEFT_BRACKET = 15;
    private static final int BRANCH_LEFT_PARENTHESIS = 2;
    private static final int BRANCH_LITERAL = 6;
    private static final int BRANCH_NONE = 0;
    private static final int BRANCH_OPERATOR = 5;
    private static final int BRANCH_RIGHT_BRACKET = 16;
    private static final int BRANCH_RIGHT_PARENTHESIS = 3;
    private static final int BRANCH_TIMESTAMP_ZONE = 19;
    private static final int IDX_ELSE = 2;
    private static final int IDX_THEN = 1;
    private static final int IDX_WHEN = 0;
    private static final LowerCaseAsciiCharSequenceObjHashMap allFunctions = new LowerCaseAsciiCharSequenceObjHashMap<>();
    private static final LowerCaseAsciiCharSequenceIntHashMap caseKeywords = new LowerCaseAsciiCharSequenceIntHashMap();
    private static final IntHashSet nonLiteralBranches = new IntHashSet();
    private final IntStack argStackDepthStack = new IntStack();
    private final IntStack backupArgStackDepthStack = new IntStack();
    private final IntStack backupCaseBraceCountStack = new IntStack();
    private final IntStack backupCastBraceCountStack = new IntStack();
    private final IntStack backupParamCountStack = new IntStack();
    private final IntStack braceCountStack = new IntStack();
    private final IntStack bracketCountStack = new IntStack();
    private final IntStack caseBraceCountStack = new IntStack();
    private final IntStack castBraceCountStack = new IntStack();
    private final CharacterStore characterStore;
    private final ObjectPool expressionNodePool;
    private final ObjStack opStack = new ObjStack<>();
    private final IntStack paramCountStack = new IntStack();
    private final SqlParser sqlParser;

    ExpressionParser(ObjectPool expressionNodePool, SqlParser sqlParser, CharacterStore characterStore) {
        this.expressionNodePool = expressionNodePool;
        this.sqlParser = sqlParser;
        this.characterStore = characterStore;
    }

    public static int extractGeoHashSuffix(int position, CharSequence tok) throws SqlException {
        assert tok.charAt(0) == '#'; // ^ ^
        // EP has already checked that the 'd' in '/d', '/dd' are numeric [0..9]
        int tokLen = tok.length();
        if (tokLen > 1) {
            if (tokLen >= 3 && tok.charAt(tokLen - 3) == '/') { // '/dd'
                short bits = (short) (10 * tok.charAt(tokLen - 2) + tok.charAt(tokLen - 1) - 528); // 10 * 48 + 48
                if (bits >= 1 && bits <= ColumnType.GEO_HASH_MAX_BITS_LENGTH) {
                    return Numbers.encodeLowHighShorts((short) 3, bits);
                }
                throw SqlException.$(position, "invalid bits size for GEOHASH constant: ").put(tok);
            }
            if (tok.charAt(tokLen - 2) == '/') { // '/d'
                char du = tok.charAt(tokLen - 1);
                if (du >= '1' && du <= '9') {
                    return Numbers.encodeLowHighShorts((short) 2, (short) (du - 48));
                }
                throw SqlException.$(position, "invalid bits size for GEOHASH constant: ").put(tok);
            }
        }
        return Numbers.encodeLowHighShorts((short) 0, (short) (5 * Math.max(tokLen - 1, 0))); // - 1 to exclude '#'
    }

    public static boolean isGeoHashBitsConstant(CharSequence tok) {
        assert tok.charAt(0) == '#'; // ^ ^, also suffix not allowed
        int len = tok.length();
        // 2nd '#'
        return len > 1 && tok.charAt(1) == '#';
    }

    public static boolean isGeoHashCharsConstant(CharSequence tok) {
        assert tok.charAt(0) == '#'; // called by ExpressionParser where this has been checked.
        // the EP will eagerly try to detect '/dd' following the geohash token, and if so
        // it will create a FloatingSequencePair with '/' as separator. At this point
        // however, '/dd' does not exist, tok is just the potential geohash chars constant, with leading '#'
        final int len = tok.length();
        return len <= 1 || tok.charAt(1) != '#';
    }

    private static SqlException missingArgs(int position) {
        return SqlException.$(position, "missing arguments");
    }

    private int copyToBackup(IntStack paramCountStack, IntStack backupParamCountStack) {
        final int size = paramCountStack.size();
        paramCountStack.copyTo(backupParamCountStack, size);
        return size;
    }

    private boolean isCount() {
        return opStack.size() == 2 && Chars.equals(opStack.peek().token, '(') && SqlKeywords.isCountKeyword(opStack.peek(1).token);
    }

    private boolean isExtractFunctionOnStack() {
        boolean found = false;
        for (int i = 0, n = opStack.size(); i < n; i++) {
            ExpressionNode peek = opStack.peek(i);
            if (Chars.equals(peek.token, '(')) {
                if ((i + 1) < n && SqlKeywords.isExtractKeyword(opStack.peek(i + 1).token)) {
                    found = true;
                    break;
                }
            }
        }
        return found;
    }

    private boolean isTypeQualifier() {
        return opStack.size() >= 2 && SqlKeywords.isColonColon(opStack.peek(1).token);
    }

    private int onNode(ExpressionParserListener listener, ExpressionNode node, int argStackDepth) throws SqlException {
        if (argStackDepth < node.paramCount) {
            throw SqlException.position(node.position).put("too few arguments for '").put(node.token).put("' [found=").put(argStackDepth).put(",expected=").put(node.paramCount).put(']');
        }
        listener.onNode(node);
        return argStackDepth - node.paramCount + 1;
    }

    private int processLambdaQuery(GenericLexer lexer, ExpressionParserListener listener, int argStackDepth) throws SqlException {
        // It is highly likely this expression parser will be re-entered when
        // parsing sub-query. To prevent sub-query consuming operation stack we must add a
        // control node, which would prevent such consumption

        // precedence must be max value to make sure control node isn't
        // consumed as parameter to a greedy function
        opStack.push(expressionNodePool.next().of(ExpressionNode.CONTROL, "|", Integer.MAX_VALUE, lexer.lastTokenPosition()));

        final int paramCountStackSize = copyToBackup(paramCountStack, backupParamCountStack);
        final int argStackDepthStackSize = copyToBackup(argStackDepthStack, backupArgStackDepthStack);
        final int castBraceCountStackSize = copyToBackup(castBraceCountStack, backupCastBraceCountStack);
        final int caseBraceCountStackSize = copyToBackup(caseBraceCountStack, backupCaseBraceCountStack);

        int pos = lexer.lastTokenPosition();
        // allow sub-query to parse "select" keyword
        lexer.unparseLast();

        ExpressionNode node = expressionNodePool.next().of(ExpressionNode.QUERY, null, 0, pos);
        // validate is Query is allowed
        onNode(listener, node, argStackDepth);
        // we can compile query if all is well
        node.queryModel = sqlParser.parseAsSubQuery(lexer, null, true);
        argStackDepth = onNode(listener, node, argStackDepth);

        // pop our control node if sub-query hasn't done it
        ExpressionNode control = opStack.peek();
        if (control != null && control.type == ExpressionNode.CONTROL && Chars.equals(control.token, '|')) {
            opStack.pop();
        }

        backupParamCountStack.copyTo(paramCountStack, paramCountStackSize);
        backupArgStackDepthStack.copyTo(argStackDepthStack, argStackDepthStackSize);
        backupCastBraceCountStack.copyTo(castBraceCountStack, castBraceCountStackSize);
        backupCaseBraceCountStack.copyTo(caseBraceCountStack, caseBraceCountStackSize);
        return argStackDepth;
    }

    void parseExpr(GenericLexer lexer, ExpressionParserListener listener) throws SqlException {
        try {
            int paramCount = 0;
            int braceCount = 0;
            int bracketCount = 0;
            int betweenCount = 0;
            int betweenAndCount = 0;
            int caseCount = 0;
            int argStackDepth = 0;
            int castAsCount = 0;
            int castBraceCount = 0;
            int betweenStartCaseCount = 0;

            ExpressionNode node;
            CharSequence tok;
            char thisChar;
            int prevBranch;
            int thisBranch = BRANCH_NONE;
            boolean asPoppedNull = false;
            OUT:
            while ((tok = SqlUtil.fetchNext(lexer)) != null) {
                thisChar = tok.charAt(0);
                prevBranch = thisBranch;
                boolean processDefaultBranch = false;
                final int lastPos = lexer.lastTokenPosition();
                switch (thisChar) {
                    case '-':
                    case '+':
                        processDefaultBranch = true;
                        if (prevBranch == BRANCH_CONSTANT) {
                            if (lastPos > 0) {
                                char c = lexer.getContent().charAt(lastPos - 1);
                                if (c == 'e' || c == 'E') { // Incomplete scientific floating-point literal
                                    ExpressionNode en = opStack.peek();
                                    ((GenericLexer.FloatingSequence) en.token).setHi(lastPos + 1);
                                    processDefaultBranch = false;
                                }
                            }
                        }
                        break;
                    case '.':
                        // Check what is on stack. If we have 'a .b' we have to stop processing
                        if (thisBranch == BRANCH_LITERAL || thisBranch == BRANCH_CONSTANT) {
                            char c = lexer.getContent().charAt(lastPos - 1);
                            if (GenericLexer.WHITESPACE_CH.contains(c)) {
                                lexer.unparseLast();
                                break OUT;
                            }

                            if (Chars.isQuote(c)) {
                                ExpressionNode en = opStack.pop();
                                CharacterStoreEntry cse = characterStore.newEntry();
                                cse.put(GenericLexer.unquote(en.token)).put('.');
                                opStack.push(expressionNodePool.next().of(ExpressionNode.LITERAL, cse.toImmutable(), Integer.MIN_VALUE, en.position));
                            } else {
                                // attach dot to existing literal or constant
                                ExpressionNode en = opStack.peek();
                                ((GenericLexer.FloatingSequence) en.token).setHi(lastPos + 1);
                            }
                        }
                        if (prevBranch == BRANCH_DOT || prevBranch == BRANCH_DOT_DEREFERENCE) {
                            throw SqlException.$(lastPos, "too many dots");
                        }

                        if (prevBranch == BRANCH_RIGHT_PARENTHESIS) {
                            thisBranch = BRANCH_DOT_DEREFERENCE;
                        } else {
                            thisBranch = BRANCH_DOT;
                        }
                        break;
                    case ',':
                        if (prevBranch == BRANCH_COMMA || prevBranch == BRANCH_LEFT_PARENTHESIS) {
                            throw missingArgs(lastPos);
                        }
                        thisBranch = BRANCH_COMMA;

                        if (braceCount == 0) {
                            // comma outside of braces
                            lexer.unparseLast();
                            break OUT;
                        }

                        if (castBraceCount > 0 && castBraceCountStack.peek() == castBraceCount) {
                            throw SqlException.$(lastPos, "',' is not expected here");
                        }

                        // If the token is a function argument separator (e.g., a comma):
                        // Until the token at the top of the stack is a left parenthesis,
                        // pop operators off the stack onto the output queue. If no left
                        // parentheses are encountered, either the separator was misplaced or
                        // parentheses were mismatched.
                        while ((node = opStack.pop()) != null && node.token.length() > 0 && node.token.charAt(0) != '(') {
                            argStackDepth = onNode(listener, node, argStackDepth);
                        }

                        if (node != null) {
                            opStack.push(node);
                        }

                        paramCount++;
                        break;

                    case '[':
                        if (isTypeQualifier()) {
                            ExpressionNode en = opStack.peek();
                            ((GenericLexer.FloatingSequence) en.token).setHi(lastPos + 1);
                        } else {
                            thisBranch = BRANCH_LEFT_BRACKET;

                            // If the token is a left parenthesis, then push it onto the stack.
                            paramCountStack.push(paramCount);
                            paramCount = 0;

                            argStackDepthStack.push(argStackDepth);
                            argStackDepth = 0;

                            // pop left literal or . expression, e.g. "a.b[i]"
                            // the precedence of [ is fixed to 2
                            ExpressionNode other;
                            while ((other = opStack.peek()) != null) {
                                if ((2 > other.precedence)) {
                                    argStackDepth = onNode(listener, other, argStackDepth);
                                    opStack.pop();
                                } else {
                                    break;
                                }
                            }

                            // precedence must be max value to make sure control node isn't
                            // consumed as parameter to a greedy function
                            opStack.push(expressionNodePool.next().of(ExpressionNode.CONTROL, "[", Integer.MAX_VALUE, lastPos));
                            bracketCount++;

                            braceCountStack.push(braceCount);
                            braceCount = 0;
                        }

                        break;

                    case ']':
                        if (isTypeQualifier()) {
                            ExpressionNode en = opStack.peek();
                            ((GenericLexer.FloatingSequence) en.token).setHi(lastPos + 1);
                        } else {
                            if (bracketCount == 0) {
                                lexer.unparseLast();
                                break OUT;
                            }

                            thisBranch = BRANCH_RIGHT_BRACKET;
                            if (prevBranch == BRANCH_LEFT_BRACKET) {
                                throw SqlException.$(lastPos, "missing array index");
                            }

                            bracketCount--;

                            // pop the array index from the stack, it could be an operator
                            while ((node = opStack.pop()) != null && (node.type != ExpressionNode.CONTROL || node.token.charAt(0) != '[')) {
                                argStackDepth = onNode(listener, node, argStackDepth);
                            }

                            if (argStackDepthStack.notEmpty()) {
                                argStackDepth += argStackDepthStack.pop();
                            }

                            if (paramCountStack.notEmpty()) {
                                paramCount = paramCountStack.pop();
                            }

                            if (braceCountStack.notEmpty()) {
                                braceCount = braceCountStack.pop();
                            }

                            node = expressionNodePool.next().of(
                                    ExpressionNode.ARRAY_ACCESS,
                                    "[]",
                                    2,
                                    lastPos
                            );
                            node.paramCount = 2;
                            opStack.push(node);
                        }

                        break;

                    case 'g':
                    case 'G':
                        if (SqlKeywords.isGeoHashKeyword(tok)) {
                            CharSequence geohashTok = GenericLexer.immutableOf(tok);
                            tok = SqlUtil.fetchNext(lexer);
                            if (tok == null || tok.charAt(0) != '(') {
                                lexer.backTo(lastPos + SqlKeywords.GEOHASH_KEYWORD_LENGTH, geohashTok);
                                tok = geohashTok;
                                processDefaultBranch = true;
                                break;
                            }
                            tok = SqlUtil.fetchNext(lexer);
                            if (tok != null && tok.charAt(0) != ')') {
                                opStack.push(expressionNodePool.next().of(
                                        ExpressionNode.CONSTANT,
                                        lexer.immutablePairOf(geohashTok, tok),
                                        Integer.MIN_VALUE,
                                        lastPos));
                                tok = SqlUtil.fetchNext(lexer);
                                if (tok == null || tok.charAt(0) != ')') {
                                    throw SqlException.$(lexer.lastTokenPosition(), "invalid GEOHASH, missing ')'");
                                }
                            } else {
                                throw SqlException.$(lexer.lastTokenPosition(), "invalid GEOHASH, invalid type precision");
                            }
                            thisBranch = BRANCH_GEOHASH;
                        } else {
                            processDefaultBranch = true;
                        }
                        break;

                    case '#':
                        if (isGeoHashCharsConstant(tok)) { // e.g. #sp052w92p1p8
                            thisBranch = BRANCH_CONSTANT;
                            CharSequence geohashTok = GenericLexer.immutableOf(tok);
                            // optional / bits '/dd', '/d'
                            CharSequence slash = SqlUtil.fetchNext(lexer);
                            if (slash == null || slash.charAt(0) != '/') {
                                lexer.unparseLast();
                                opStack.push(expressionNodePool.next().of(
                                        ExpressionNode.CONSTANT,
                                        geohashTok, // standard token, no suffix '/d', '/dd'
                                        Integer.MIN_VALUE,
                                        lastPos));
                                break;
                            }
                            tok = SqlUtil.fetchNext(lexer);
                            if (tok == null || !Chars.isOnlyDecimals(tok)) { // ranges are checked later by FunctionParser.createConstant
                                throw SqlException.$(lexer.lastTokenPosition(), "missing bits size for GEOHASH constant");
                            }
                            opStack.push(expressionNodePool.next().of(
                                    ExpressionNode.CONSTANT,
                                    lexer.immutablePairOf(geohashTok, '/', tok), // token plus suffix '/d', '/dd', where d in [0..9]
                                    Integer.MIN_VALUE,
                                    lastPos));
                            break;
                        }

                        if (isGeoHashBitsConstant(tok)) { // e.g. ##01110001
                            thisBranch = BRANCH_CONSTANT;
                            opStack.push(expressionNodePool.next().of(
                                    ExpressionNode.CONSTANT,
                                    GenericLexer.immutableOf(tok), // geohash bit literals do not allow suffix syntax
                                    Integer.MIN_VALUE,
                                    lastPos));
                            break;
                        }

                        processDefaultBranch = true;
                        break;

                    case '(':
                        if (prevBranch == BRANCH_RIGHT_PARENTHESIS) {
                            throw SqlException.$(lastPos, "not a method call");
                        }

                        thisBranch = BRANCH_LEFT_PARENTHESIS;
                        // If the token is a left parenthesis, then push it onto the stack.
                        paramCountStack.push(paramCount);
                        paramCount = 0;

                        argStackDepthStack.push(argStackDepth);
                        argStackDepth = 0;

                        bracketCountStack.push(bracketCount);
                        bracketCount = 0;

                        // precedence must be max value to make sure control node isn't
                        // consumed as parameter to a greedy function
                        opStack.push(expressionNodePool.next().of(ExpressionNode.CONTROL, "(", Integer.MAX_VALUE, lastPos));

                        // check if this brace was opened after 'cast'
                        if (castBraceCountStack.size() > 0 && castBraceCountStack.peek() == -1) {
                            castBraceCountStack.update(castBraceCount + 1);
                        }
                        // if this brace is inside a 'cast', use the helper counter to parse inner braces
                        if (castBraceCountStack.size() > 0) {
                            castBraceCount++;
                        }

                        braceCount++;
                        break;

                    case ')':
                        if (prevBranch == BRANCH_COMMA) {
                            throw missingArgs(lastPos);
                        }

                        if (braceCount == 0) {
                            lexer.unparseLast();
                            break OUT;
                        }

                        thisBranch = BRANCH_RIGHT_PARENTHESIS;
                        int localParamCount = (prevBranch == BRANCH_LEFT_PARENTHESIS ? 0 : paramCount + 1);
                        final boolean thisWasCast;

                        if (castBraceCountStack.size() > 0 && castBraceCountStack.peek() == castBraceCount) {
                            if (castAsCount == 0) {
                                throw SqlException.$(lastPos, "'as' missing");
                            }

                            castAsCount--;
                            castBraceCountStack.pop();
                            thisWasCast = true;
                        } else {
                            thisWasCast = false;
                        }

                        if (castBraceCount > 0) {
                            castBraceCount--;
                        }

                        braceCount--;
                        // If the token is a right parenthesis:
                        // Until the token at the top of the stack is a left parenthesis, pop operators off the stack onto the output queue.
                        // Pop the left parenthesis from the stack, but not onto the output queue.
                        //        If the token at the top of the stack is a function token, pop it onto the output queue.
                        //        If the stack runs out without finding a left parenthesis, then there are mismatched parentheses.
                        while ((node = opStack.pop()) != null && (node.token.length() == 0 || node.token.charAt(0) != '(')) {
                            // special case - (*) expression
                            if (Chars.equals(node.token, '*') && argStackDepth == 0 && isCount()) {
                                argStackDepth = onNode(listener, node, 2);
                            } else {
                                if (thisWasCast) {
                                    if (prevBranch != BRANCH_GEOHASH) {
                                        // validate type
                                        final short columnTypeTag = ColumnType.tagOf(node.token);
                                        if (((columnTypeTag < ColumnType.BOOLEAN || (columnTypeTag > ColumnType.LONG256 && columnTypeTag != ColumnType.UUID)) && !asPoppedNull) ||
                                                (columnTypeTag == ColumnType.GEOHASH && node.type == ExpressionNode.LITERAL)) {
                                            throw SqlException.$(node.position, "unsupported cast");
                                        }
                                        node.type = ExpressionNode.CONSTANT;
                                    }
                                }
                                argStackDepth = onNode(listener, node, argStackDepth);
                            }
                        }

                        if (argStackDepthStack.notEmpty()) {
                            argStackDepth += argStackDepthStack.pop();
                        }

                        // enable operation or literal absorb parameters
                        if ((node = opStack.peek()) != null && (node.type == ExpressionNode.LITERAL || (node.type == ExpressionNode.SET_OPERATION))) {
                            if (!SqlKeywords.isBetweenKeyword(node.token) || betweenCount == betweenAndCount) {
                                node.paramCount = localParamCount + Math.max(0, node.paramCount - 1);
                                if (ExpressionNode.SET_OPERATION == node.type && node.paramCount < 2) {
                                    throw SqlException.position(node.position).put("too few arguments for '").put(node.token).put('\'');
                                }
                                node.type = ExpressionNode.FUNCTION;
                                argStackDepth = onNode(listener, node, argStackDepth);
                                opStack.pop();
                            }
                        } else {
                            // not at function?
                            // peek the op stack to make sure it isn't a repeating brace
                            if (localParamCount > 1
                                    && (node = opStack.peek()) != null
                                    && node.token.charAt(0) == '('
                            ) {
                                throw SqlException.$(lastPos, "no function or operator?");
                            }
                        }

                        if (paramCountStack.notEmpty()) {
                            paramCount = paramCountStack.pop();
                        }

                        if (bracketCountStack.notEmpty()) {
                            bracketCount = bracketCountStack.pop();
                        }

                        break;
                    case 'c':
                    case 'C':
                        if (SqlKeywords.isCastKeyword(tok)) {
                            CharSequence caseTok = GenericLexer.immutableOf(tok);
                            tok = SqlUtil.fetchNext(lexer);
                            if (tok == null || tok.charAt(0) != '(') {
                                lexer.backTo(lastPos + SqlKeywords.CASE_KEYWORD_LENGTH, caseTok);
                                tok = caseTok;
                                processDefaultBranch = true;
                                break;
                            }

                            lexer.backTo(lastPos + SqlKeywords.CASE_KEYWORD_LENGTH, caseTok);
                            tok = caseTok;
                            if (prevBranch != BRANCH_DOT_DEREFERENCE) {
                                castBraceCountStack.push(-1);
                                thisBranch = BRANCH_OPERATOR;
                                opStack.push(expressionNodePool.next().of(ExpressionNode.LITERAL, "cast", Integer.MIN_VALUE, lastPos));
                                break;
                            } else {
                                throw SqlException.$(lastPos, "'cast' is not allowed here");
                            }
                        }
                        processDefaultBranch = true;
                        break;
                    case 'a':
                    case 'A':
                        if (SqlKeywords.isAsKeyword(tok)) {
                            if (castAsCount < castBraceCountStack.size()) {

                                thisBranch = BRANCH_CAST_AS;

                                // push existing args to the listener
                                int nodeCount = 0;
                                while ((node = opStack.pop()) != null && node.token.charAt(0) != '(') {
                                    nodeCount++;
                                    asPoppedNull = SqlKeywords.isNullKeyword(node.token);
                                    argStackDepth = onNode(listener, node, argStackDepth);
                                }

                                if (nodeCount != 1) {
                                    asPoppedNull = false;
                                }

                                if (node != null) {
                                    opStack.push(node);
                                }

                                paramCount++;
                                castAsCount++;
                            } else {
                                processDefaultBranch = true;
                            }
                        } else if (SqlKeywords.isAndKeyword(tok)) {
                            if (caseCount == betweenStartCaseCount && betweenCount > betweenAndCount) {
                                betweenAndCount++;
                                thisBranch = BRANCH_BETWEEN_END;
                                while ((node = opStack.pop()) != null && !SqlKeywords.isBetweenKeyword(node.token)) {
                                    argStackDepth = onNode(listener, node, argStackDepth);
                                }

                                if (node != null) {
                                    opStack.push(node);
                                }
                            } else {
                                processDefaultBranch = true;
                            }
                        } else if (SqlKeywords.isAllKeyword(tok)) {
                            ExpressionNode operator = opStack.peek();
                            if (operator == null || operator.type != ExpressionNode.OPERATION) {
                                throw SqlException.$(lastPos, "missing operator");
                            }
                            CharSequence funcName = allFunctions.get(operator.token);
                            if (funcName != null && operator.paramCount == 2) {
                                operator.type = ExpressionNode.FUNCTION;
                                operator.token = funcName;
                            } else {
                                throw SqlException.$(operator.position, "unexpected operator");
                            }
                        } else if ((prevBranch == BRANCH_LITERAL || prevBranch == BRANCH_CONSTANT || prevBranch == BRANCH_RIGHT_PARENTHESIS) && SqlKeywords.isAtKeyword(tok)) {
                            int pos = lexer.getPosition();
                            // '.' processing expects floating char sequence
                            CharSequence atTok = GenericLexer.immutableOf(tok);
                            tok = SqlUtil.fetchNext(lexer);
                            if (tok != null && SqlKeywords.isTimeKeyword(tok)) {
                                tok = SqlUtil.fetchNext(lexer);
                                if (tok != null && SqlKeywords.isZoneKeyword(tok)) {
                                    // do the zone thing
                                    thisBranch = BRANCH_TIMESTAMP_ZONE;
                                } else {
                                    throw SqlException.$(
                                            tok == null ? lexer.getPosition() : lexer.lastTokenPosition(),
                                            "did you mean 'at time zone '?"
                                    );
                                }
                            } else {
                                tok = atTok;
                                // non-literal branches use 'tok' to create expressions
                                // however literal branches exit, pushing literal back into lexer (unparse)
                                // so for non-literal branches we have to preserve the very last token we
                                // had to peek at
                                if (caseCount > 0 || nonLiteralBranches.excludes(thisBranch)) {
                                    lexer.unparseLast();
                                } else {
                                    lexer.unparse(tok, lastPos, pos);
                                }
                                processDefaultBranch = true;
                            }

                        } else {
                            processDefaultBranch = true;
                        }
                        break;
                    case 'b':
                    case 'B':
                        if (SqlKeywords.isBetweenKeyword(tok)) {
                            thisBranch = BRANCH_BETWEEN_START;
                            if (betweenCount > betweenAndCount) {
                                // Nested between are not supported
                                throw SqlException.$(lastPos, "between statements cannot be nested");
                            }
                            betweenCount++;
                            betweenStartCaseCount = caseCount;
                        }
                        processDefaultBranch = true;
                        break;
                    case 's':
                    case 'S':
                        if (SqlKeywords.isSelectKeyword(tok)) {
                            thisBranch = BRANCH_LAMBDA;
                            if (betweenCount > 0) {
                                throw SqlException.$(lastPos, "constant expected");
                            }
                            argStackDepth = processLambdaQuery(lexer, listener, argStackDepth);
                        } else {
                            processDefaultBranch = true;
                        }
                        break;
                    case '0':
                    case '1':
                    case '2':
                    case '3':
                    case '4':
                    case '5':
                    case '6':
                    case '7':
                    case '8':
                    case '9':
                    case '\'':
                    case 'E':

                        if (prevBranch != BRANCH_DOT_DEREFERENCE) {
                            // check if this is E'str'
                            if (thisChar == 'E' && (tok.length() < 3 || tok.charAt(1) != '\'')) {
                                processDefaultBranch = true;
                                break;
                            }

                            thisBranch = BRANCH_CONSTANT;
                            if (prevBranch == BRANCH_CONSTANT && lastPos > 0) {
                                char prevChar = lexer.getContent().charAt(lastPos - 1);
                                if (prevChar == '-' || prevChar == '+') {
                                    final ExpressionNode en = opStack.peek();
                                    if (en.token instanceof GenericLexer.FloatingSequence) {
                                        ((GenericLexer.FloatingSequence) en.token).setHi(lexer.getTokenHi());
                                        break;
                                    } else {
                                        assert false;
                                    }
                                }
                            }
                            if (prevBranch == BRANCH_DOT) {
                                final ExpressionNode en = opStack.peek();
                                if (en != null && en.type != ExpressionNode.CONTROL && en.type != ExpressionNode.OPERATION) {
                                    // check if this is '1.2' or '1. 2'
                                    if (lastPos > 0 && lexer.getContent().charAt(lastPos - 1) == '.') {
                                        if (en.token instanceof GenericLexer.FloatingSequence) {
                                            ((GenericLexer.FloatingSequence) en.token).setHi(lexer.getTokenHi());
                                        } else {
                                            opStack.pop();
                                            CharacterStoreEntry cse = characterStore.newEntry();
                                            cse.put(en.token).put(GenericLexer.unquote(tok));
                                            opStack.push(expressionNodePool.next().of(ExpressionNode.LITERAL, cse.toImmutable(), Integer.MIN_VALUE, en.position));
                                        }
                                        break;
                                    }
                                } else {
                                    opStack.push(
                                            expressionNodePool.next().of(
                                                    ExpressionNode.CONSTANT,
                                                    lexer.immutableBetween(lastPos - 1, lexer.getTokenHi()),
                                                    0,
                                                    lastPos
                                            )
                                    );
                                    break;
                                }
                            }
                            if (prevBranch != BRANCH_DOT && nonLiteralBranches.excludes(prevBranch)) {
                                if (SqlKeywords.isQuote(tok)) {
                                    throw SqlException.$(lastPos, "unclosed quoted string?");
                                }

                                ExpressionNode constNode = expressionNodePool.next().of(ExpressionNode.CONSTANT,
                                        GenericLexer.immutableOf(tok),
                                        0,
                                        lastPos
                                );

                                if (prevBranch == BRANCH_TIMESTAMP_ZONE) {
                                    argStackDepth = onNode(
                                            listener,
                                            constNode,
                                            argStackDepth
                                    );

                                    // replace const node with 'to_timezone' function node
                                    constNode = expressionNodePool.next().of(ExpressionNode.FUNCTION,
                                            "to_timezone",
                                            Integer.MIN_VALUE,
                                            lastPos
                                    );
                                    constNode.paramCount = 2;
                                    // fall thru
                                }
                                opStack.push(constNode);
                                break;
                            } else {
                                if (opStack.size() > 0 && prevBranch == BRANCH_LITERAL && thisChar == '\'') {
                                    ExpressionNode prevNode = opStack.pop();
                                    // This is postgres syntax to cast string literal to a type
                                    // timestamp '2005-04-02 12:00:00-07'
                                    // long '12321312'
                                    // timestamp with time zone '2005-04-02 12:00:00-07'

                                    // validate type
                                    final short columnType = ColumnType.tagOf(prevNode.token);
                                    if ((columnType < ColumnType.BOOLEAN || (columnType > ColumnType.LONG256 && columnType != ColumnType.UUID)) && (columnType != ColumnType.IPv4)) {
                                        throw SqlException.$(prevNode.position, "invalid type");
                                    } else {
                                        ExpressionNode stringLiteral = expressionNodePool.next().of(ExpressionNode.CONSTANT, GenericLexer.immutableOf(tok), 0, lastPos);
                                        onNode(listener, stringLiteral, 0);

                                        prevNode.type = ExpressionNode.CONSTANT;
                                        onNode(listener, prevNode, 0);

                                        ExpressionNode cast = expressionNodePool.next().of(ExpressionNode.FUNCTION, "cast", 0, prevNode.position);
                                        cast.paramCount = 2;

                                        onNode(listener, cast, argStackDepth + 2);
                                        argStackDepth++;
                                        break;
                                    }
                                }

                                if (opStack.size() > 1) {
                                    throw SqlException.$(lastPos, "dangling expression");
                                }
                                lexer.unparseLast();
                                break OUT;
                            }
                        } else {
                            throw SqlException.$(lastPos, "constant is not allowed here");
                        }
                    case 'N':
                    case 'n':
                        if (SqlKeywords.isNotKeyword(tok)) {
                            ExpressionNode nn = opStack.peek();
                            if (nn != null && nn.type == ExpressionNode.LITERAL) {
                                opStack.pop();

                                node = expressionNodePool.next().of(
                                        ExpressionNode.OPERATION,
                                        GenericLexer.immutableOf(tok),
                                        11,
                                        lastPos
                                );
                                node.paramCount = 1;
                                opStack.push(node);
                                opStack.push(nn);
                                break;
                            }
                        }
                    case 't':
                    case 'T':
                    case 'f':
                    case 'F':
                        if (SqlKeywords.isNanKeyword(tok)
                                || SqlKeywords.isNullKeyword(tok)
                                || SqlKeywords.isTrueKeyword(tok)
                                || SqlKeywords.isFalseKeyword(tok)
                        ) {
                            if (prevBranch != BRANCH_DOT_DEREFERENCE) {
                                thisBranch = BRANCH_CONSTANT;
                                // If the token is a number, then add it to the output queue.
                                opStack.push(expressionNodePool.next().of(ExpressionNode.CONSTANT, GenericLexer.immutableOf(tok), 0, lastPos));
                            } else {
                                throw SqlException.$(lastPos, "constant is not allowed here");
                            }
                            break;
                        }
                        processDefaultBranch = true;
                        break;
                    case 'i':
                    case 'I':
                        if (SqlKeywords.isIsKeyword(tok)) {
                            // replace:
                            //  IS NULL     ->  = NULL
                            //  IS NOT NULL ->  != NULL
                            if (prevBranch == BRANCH_LITERAL || prevBranch == BRANCH_CONSTANT || prevBranch == BRANCH_RIGHT_PARENTHESIS) {
                                final CharSequence isTok = GenericLexer.immutableOf(tok);
                                tok = SqlUtil.fetchNext(lexer);
                                if (tok == null) {
                                    throw SqlException.$(lastPos, "IS must be followed by [NOT] NULL");
                                }
                                if (SqlKeywords.isNotKeyword(tok)) {
                                    final int notTokPosition = lexer.lastTokenPosition();
                                    final CharSequence notTok = GenericLexer.immutableOf(tok);
                                    tok = SqlUtil.fetchNext(lexer);
                                    if (tok != null && SqlKeywords.isNullKeyword(tok)) {
                                        lexer.backTo(notTokPosition + 3, notTok);
                                        tok = "!=";
                                    } else {
                                        throw SqlException.$(lastPos, "IS NOT must be followed by NULL");
                                    }
                                } else if (SqlKeywords.isNullKeyword(tok)) {
                                    lexer.backTo(lastPos + 2, isTok);
                                    tok = "=";
                                } else {
                                    throw SqlException.$(lastPos, "IS must be followed by NULL");
                                }
                            } else {
                                throw SqlException.$(lastPos, "IS [NOT] not allowed here");
                            }
                        }
                        processDefaultBranch = true;
                        break;
                    case '*':
                        // special case for tab.*
                        if (prevBranch == BRANCH_DOT) {
                            thisBranch = BRANCH_LITERAL;
                            final ExpressionNode en = opStack.peek();
                            if (en != null && en.type != ExpressionNode.CONTROL) {
                                // leverage the fact '*' is dedicated token and it returned from cache
                                // therefore lexer.tokenHi does not move when * follows dot without whitespace
                                // e.g. 'a.*'
                                if (GenericLexer.WHITESPACE_CH.excludes(lexer.getContent().charAt(lastPos - 1))) {
                                    if (en.token instanceof GenericLexer.FloatingSequence) {
                                        GenericLexer.FloatingSequence fs = (GenericLexer.FloatingSequence) en.token;
                                        fs.setHi(lastPos + 1);
                                    } else {
                                        // "foo".* or 'foo'.*
                                        // foo was unquoted, and we cannot simply move hi to include the *
                                        opStack.pop();
                                        CharacterStoreEntry cse = characterStore.newEntry();
                                        cse.put(en.token).put('*');
                                        opStack.push(expressionNodePool.next().of(ExpressionNode.LITERAL, cse.toImmutable(), Integer.MIN_VALUE, en.position));
                                    }
                                } else {
                                    // in this case we have whitespace, e.g. 'a. *'
                                    processDefaultBranch = true;
                                }
                            } else {
                                opStack.push(
                                        expressionNodePool.next().of(
                                                ExpressionNode.CONSTANT,
                                                lexer.immutableBetween(lastPos - 1, lexer.getTokenHi()),
                                                0,
                                                lastPos
                                        )
                                );
                            }
                            break;
                        }
                    default:
                        processDefaultBranch = true;
                        break;
                }

                if (processDefaultBranch) {
                    OperatorExpression op;
                    if ((op = OperatorExpression.opMap.get(tok)) != null) {

                        thisBranch = BRANCH_OPERATOR;

                        // If the token is an operator, o1, then:
                        // while there is an operator token, o2, at the top of the operator stack, and either
                        // o1 is left-associative and its precedence is less than or equal to that of o2, or
                        // o1 is right associative, and has precedence less than that of o2,
                        //        then pop o2 off the operator stack, onto the output queue;
                        // push o1 onto the operator stack.

                        int operatorType = op.type;

                        if (thisChar == '-' || thisChar == '~') {
                            switch (prevBranch) {
                                case BRANCH_OPERATOR:
                                case BRANCH_LEFT_PARENTHESIS:
                                case BRANCH_COMMA:
                                case BRANCH_NONE:
                                case BRANCH_CASE_CONTROL:
                                    // we have unary minus
                                    operatorType = OperatorExpression.UNARY;
                                    break;
                                default:
                                    break;
                            }
                        }

                        ExpressionNode other;
                        // UNARY operators must never pop BINARY ones regardless of precedence
                        // this is to maintain correctness of -a^b
                        while ((other = opStack.peek()) != null) {
                            boolean greaterPrecedence = (op.leftAssociative && op.precedence >= other.precedence) || (!op.leftAssociative && op.precedence > other.precedence);
                            if (greaterPrecedence &&
                                    (operatorType != OperatorExpression.UNARY || (operatorType == OperatorExpression.UNARY && other.paramCount == 1))) {
                                argStackDepth = onNode(listener, other, argStackDepth);
                                opStack.pop();
                            } else {
                                break;
                            }
                        }
                        node = expressionNodePool.next().of(
                                op.type == OperatorExpression.SET ? ExpressionNode.SET_OPERATION : ExpressionNode.OPERATION,
                                op.token,
                                op.precedence,
                                lastPos
                        );
                        if (operatorType == OperatorExpression.UNARY) {
                            node.paramCount = 1;
                        } else if (SqlKeywords.isBetweenKeyword(node.token)) {
                            node.paramCount = 3;
                        } else {
                            node.paramCount = 2;
                        }
                        opStack.push(node);
                    } else if (caseCount > 0 || nonLiteralBranches.excludes(thisBranch)) {
                        // here we handle literals, in case of "case" statement some of these literals
                        // are going to flush operation stack
                        if (Chars.toLowerCaseAscii(thisChar) == 'c' && SqlKeywords.isCaseKeyword(tok)) {
                            if (prevBranch != BRANCH_DOT_DEREFERENCE) {
                                caseCount++;
                                paramCountStack.push(paramCount);
                                paramCount = 0;

                                caseBraceCountStack.push(braceCount);
                                braceCount = 0;

                                argStackDepthStack.push(argStackDepth);
                                argStackDepth = 0;
                                opStack.push(expressionNodePool.next().of(ExpressionNode.FUNCTION, "case", Integer.MAX_VALUE, lastPos));
                                thisBranch = BRANCH_CASE_START;
                                continue;
                            } else {
                                throw SqlException.$(lastPos, "'case' is not allowed here");
                            }
                        }

                        thisBranch = BRANCH_LITERAL;

                        if (caseCount > 0) {
                            switch (Chars.toLowerCaseAscii(thisChar)) {
                                case 'e':
                                    if (SqlKeywords.isEndKeyword(tok)) {
                                        if (prevBranch == BRANCH_CASE_CONTROL) {
                                            throw missingArgs(lastPos);
                                        }

                                        if (paramCount == 0) {
                                            throw SqlException.$(lastPos, "'when' expected");
                                        }

                                        if (paramCount <= 2) {
                                            throw SqlException.$(lastPos, "'then' expected");
                                        }

                                        // If the token is a right parenthesis:
                                        // Until the token at the top of the stack is a left parenthesis, pop operators off the stack onto the output queue.
                                        // Pop the left parenthesis from the stack, but not onto the output queue.
                                        //        If the token at the top of the stack is a function token, pop it onto the output queue.
                                        //        If the stack runs out without finding a left parenthesis, then there are mismatched parentheses.
                                        while ((node = opStack.pop()) != null && !SqlKeywords.isCaseKeyword(node.token)) {
                                            argStackDepth = onNode(listener, node, argStackDepth);
                                        }

                                        // 'when/else' have been clearing argStackDepth to ensure
                                        // expressions between 'when' and 'when' do not pick up arguments outside of scope
                                        // now we need to restore stack depth before 'case' entry
                                        if (argStackDepthStack.notEmpty()) {
                                            argStackDepth += argStackDepthStack.pop();
                                        }

                                        if (caseBraceCountStack.notEmpty()) {
                                            braceCount = caseBraceCountStack.pop();
                                        }

                                        node.paramCount = paramCount;
                                        // we also add number of 'case' arguments to original stack depth
                                        argStackDepth = onNode(listener, node, argStackDepth + paramCount);

                                        // make sure we restore paramCount
                                        if (paramCountStack.notEmpty()) {
                                            paramCount = paramCountStack.pop();
                                        }

                                        caseCount--;
                                        continue;
                                    }
                                    // fall through
                                case 'w':
                                case 't':
                                    int keywordIndex = caseKeywords.get(tok);
                                    if (keywordIndex > -1) {

                                        if (prevBranch == BRANCH_CASE_CONTROL) {
                                            throw missingArgs(lastPos);
                                        }
                                        if (keywordIndex == IDX_ELSE && paramCount == 0) {
                                            throw SqlException.$(lastPos, "'when' expected");
                                        }

                                        // we need to track argument consumption so that operators and functions
                                        // do no steal parameters outside of local 'case' scope
                                        int argCount = 0;
                                        while ((node = opStack.pop()) != null && !SqlKeywords.isCaseKeyword(node.token)) {
                                            argStackDepth = onNode(listener, node, argStackDepth);
                                            argCount++;
                                        }

                                        if (paramCount == 0) {
                                            if (argCount == 0) {
                                                // this is 'case when', we will indicate that this is regular 'case' to the rewrite logic
                                                onNode(listener, expressionNodePool.next().of(ExpressionNode.LITERAL, null, Integer.MIN_VALUE, -1), argStackDepth);
                                            }
                                            paramCount++;
                                        }

                                        switch (keywordIndex) {
                                            case IDX_WHEN:
                                            case IDX_ELSE:
                                                if ((paramCount % 2) == 0) {
                                                    throw SqlException.$(lastPos, "'then' expected");
                                                }
                                                break;
                                            default: // then
                                                if ((paramCount % 2) != 0) {
                                                    throw SqlException.$(lastPos, "'when' expected");
                                                }
                                                break;
                                        }

                                        if (node != null) {
                                            opStack.push(node);
                                        }

                                        argStackDepth = 0;
                                        paramCount++;
                                        thisBranch = BRANCH_CASE_CONTROL;
                                        continue;
                                    }
                                    break;
                                default:
                                    break;
                            }
                        }

                        if (prevBranch == BRANCH_DOT) {
                            // this deals with 'table.column' situations
                            ExpressionNode en = opStack.peek();
                            if (en == null) {
                                throw SqlException.$(lastPos, "qualifier expected");
                            }
                            // two possibilities here:
                            // 1. 'a.b'
                            // 2. 'a. b'

                            if (GenericLexer.WHITESPACE_CH.contains(lexer.getContent().charAt(lastPos - 1))) {
                                // 'a. b'
                                lexer.unparseLast();
                                break;
                            }

                            if (Chars.isQuoted(tok) || en.token instanceof CharacterStore.NameAssemblerCharSequence) {
                                // replacing node, must remove old one from stack
                                opStack.pop();
                                // this was more analogous to 'a."b"'
                                CharacterStoreEntry cse = characterStore.newEntry();
                                cse.put(en.token).put(GenericLexer.unquote(tok));
                                opStack.push(expressionNodePool.next().of(ExpressionNode.LITERAL, cse.toImmutable(), Integer.MIN_VALUE, en.position));
                            } else {
                                final GenericLexer.FloatingSequence fsA = (GenericLexer.FloatingSequence) en.token;
                                // vanilla 'a.b', just concat tokens efficiently
                                fsA.setHi(lexer.getTokenHi());
                            }
                        } else if (prevBranch != BRANCH_DOT_DEREFERENCE) {
                            // If the token is a function token, then push it onto the stack.
                            opStack.push(expressionNodePool.next().of(ExpressionNode.LITERAL, GenericLexer.unquote(tok), Integer.MIN_VALUE, lastPos));
                        } else {
                            argStackDepth++;
                            final ExpressionNode dotDereference = expressionNodePool.next().of(ExpressionNode.OPERATION, ".", DOT_PRECEDENCE, lastPos);
                            dotDereference.paramCount = 2;
                            opStack.push(dotDereference);
                            opStack.push(expressionNodePool.next().of(ExpressionNode.MEMBER_ACCESS, GenericLexer.unquote(tok), Integer.MIN_VALUE, lastPos));
                        }
                    } else {
                        ExpressionNode last = this.opStack.peek();
                        // Handle `timestamp with time zone`
                        if (last != null) {
                            if (SqlKeywords.isTimestampKeyword(last.token) && SqlKeywords.isWithKeyword(tok)) {
                                CharSequence withTok = GenericLexer.immutableOf(tok);
                                int withTokPosition = lexer.getPosition();
                                tok = SqlUtil.fetchNext(lexer);
                                if (tok != null && SqlKeywords.isTimeKeyword(tok)) {
                                    tok = SqlUtil.fetchNext(lexer);
                                    if (tok != null && SqlKeywords.isZoneKeyword(tok)) {
                                        CharSequence zoneTok = GenericLexer.immutableOf(tok);
                                        int zoneTokPosition = lexer.getTokenHi();
                                        tok = SqlUtil.fetchNext(lexer);
                                        // Next token is string literal, or we are in 'as' part of cast function
                                        boolean isInActiveCastAs = (castBraceCountStack.size() > 0 && (castBraceCountStack.size() == castAsCount));
                                        if (tok != null && (isInActiveCastAs || tok.charAt(0) == '\'')) {
                                            lexer.backTo(zoneTokPosition, zoneTok);
                                            continue;
                                        }
                                        throw SqlException.$(zoneTokPosition, "String literal expected after 'timestamp with time zone'");
                                    }
                                }
                                lexer.backTo(withTokPosition, withTok);
                            } else if (SqlKeywords.isFromKeyword(tok)) {
                                // check if this is "extract(something from ...)"
                                // we can do this by analyzing opStack
                                if (opStack.size() > 2) {
                                    boolean extractError = true;
                                    ExpressionNode member = opStack.peek(0);
                                    if (member.type == ExpressionNode.LITERAL || (member.type == ExpressionNode.CONSTANT)) {
                                        if (Chars.equals(opStack.peek(1).token, '(')) {
                                            if (SqlKeywords.isExtractKeyword(opStack.peek(2).token)) {
                                                // validate part
                                                if (SqlKeywords.validateExtractPart(GenericLexer.unquote(member.token))) {
                                                    // in this case "from" keyword acts as ',' in function call
                                                    member.type = ExpressionNode.MEMBER_ACCESS;
                                                    argStackDepth = onNode(
                                                            listener,
                                                            member,
                                                            argStackDepth
                                                    );
                                                    opStack.pop();
                                                    paramCount++;
                                                    thisBranch = BRANCH_COMMA;
                                                    continue;
                                                } else {
                                                    throw SqlException.$(member.position, "unsupported timestamp part: ").put(member.token);
                                                }
                                            } else {
                                                extractError = false;
                                            }
                                        }
                                    }

                                    // report error on extract
                                    if (extractError && isExtractFunctionOnStack()) {
                                        throw SqlException.$(member.position, "we expect timestamp part here");
                                    }

                                }
                            }
                        }
                        // literal can be at start of input, after a bracket or part of an operator
                        // all other cases are illegal and will be considered end-of-input
                        lexer.unparseLast();
                        break;
                    }
                }
            }

            if (thisBranch == BRANCH_TIMESTAMP_ZONE) {
                throw SqlException.$(lexer.lastTokenPosition(), "did you mean 'at time zone '?");
            }

            while ((node = opStack.pop()) != null) {

                if (node.token.length() != 0 && node.token.charAt(0) == '(') {
                    throw SqlException.$(node.position, "unbalanced (");
                }

                // our array dereference is dangling
                if (node.type == ExpressionNode.CONTROL && node.token.charAt(0) == '[') {
                    throw SqlException.$(node.position, "unbalanced ]");
                }

                if (SqlKeywords.isCaseKeyword(node.token)) {
                    throw SqlException.$(node.position, "unbalanced 'case'");
                }

                if (node.type == ExpressionNode.CONTROL) {
                    // break on any other control node to allow parser to be re-enterable
                    // put control node back on stack because we don't own it
                    opStack.push(node);
                    break;
                }

                argStackDepth = onNode(listener, node, argStackDepth);
            }

        } catch (SqlException e) {
            opStack.clear();
            backupCastBraceCountStack.clear();
            backupParamCountStack.clear();
            backupArgStackDepthStack.clear();
            throw e;
        } finally {
            argStackDepthStack.clear();
            paramCountStack.clear();
            castBraceCountStack.clear();
            caseBraceCountStack.clear();
        }
    }

    static {
        nonLiteralBranches.add(BRANCH_RIGHT_PARENTHESIS);
        nonLiteralBranches.add(BRANCH_CONSTANT);
        nonLiteralBranches.add(BRANCH_LITERAL);
        nonLiteralBranches.add(BRANCH_LAMBDA);

        caseKeywords.put("when", IDX_WHEN);
        caseKeywords.put("then", IDX_THEN);
        caseKeywords.put("else", IDX_ELSE);

        allFunctions.put("<>", "<>all");
        allFunctions.put("!=", "<>all");
    }
}




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