expression.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
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#ifndef BAGEL_BAGLIB_EXPRESSION_H
#define BAGEL_BAGLIB_EXPRESSION_H

#include "bagel/baglib/parse_object.h"
#include "bagel/baglib/var.h"
#include "bagel/boflib/list.h"

namespace Bagel {

class CBagExpression : public CBagParseObject, public CBofObject {
public:
    enum OPERATION {
        OP_NONE,
        OP_ASSIGN,
        OP_EQUAL,
        OP_NOT_EQUAL,
        OP_LESS_THAN,
        OP_LESS_THAN_EQUAL,
        OP_GREATER_THAN,
        OP_GREATER_THAN_EQUAL,
        OP_PLUS_ASSIGN,
        OP_MINUS_ASSIGN,
        OP_CONTAINS,
        OP_HAS,
        OP_CURR_SDEV,
        OP_PLUS,
        OP_MINUS,
        OP_MULTIPLY,
        OP_DIVIDE,
        OP_AND,
        OP_OR,
        OP_MOD,
        OP_STATUS
    };

private:
    CBofList<CBagVar *> _varList;    // Right hand operator
    CBofList<OPERATION> _operList;   // Operation to be preformed
    CBagExpression *_prevExpression; // Not null when when this is an enclosed expression

    bool _prevNegativeFl; // True if the operation should return Negative results
    bool _negativeFl;     // True if the operation should return Negative results

    bool evaluate(CBagVar *leftHandOper, CBagVar *rightHandOper, OPERATION oper, CBagVar &result);

public:
    static CBagVar *_tempVar; // Used as a default param
    static void initialize();
    static void shutdown();

    CBagExpression(CBagExpression *prevExpr = nullptr, bool prevNegFl = false);
    virtual ~CBagExpression();

    bool evaluate(bool negFl = false, CBagVar &result = *_tempVar);

    bool evalLeftToRight(bool negFl = false, CBagVar &result = *_tempVar);

    bool negEvaluate(CBagVar &result = *_tempVar);

    void setNegative(bool b = true) {
        _negativeFl = b;
    }
    bool isNegative() const {
        return _negativeFl;
    }

    CBagVar *getVariable(int itemPos);
    OPERATION getOperation(int itemPos);

    ParseCodes setInfo(CBagIfstream &istr) override;
    ErrorCode getOperatorFromStream(CBagIfstream &istr, OPERATION &oper);

    CBagExpression *getPrevExpression() const {
        return _prevExpression;
    }
    void setPrevExpression(CBagExpression *expr) {
        _prevExpression = expr;
    }

    virtual bool onAssign(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onEqual(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onNotEqual(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onLessThan(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onGreaterThan(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onLessThanEqual(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onGreaterThanEqual(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onPlusAssign(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onMinusAssign(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onContains(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onHas(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onCurrSDev(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onPlus(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onMinus(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onMultiply(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onDivide(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onMod(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onAnd(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onOr(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
    virtual bool onStatus(CBagVar *leftHandOper, CBagVar *rightHandOper, CBagVar &resultOper);
};

} // namespace Bagel

#endif