#include <QtGui>#include "cell.h"Cell::Cell(){    setDirty();}QTableWidgetItem *Cell::clone() const{    return new Cell(*this);}void Cell::setData(int role, const QVariant &value){    QTableWidgetItem::setData(role, value);    if (role == Qt::EditRole)        setDirty();}QVariant Cell::data(int role) const{    if (role == Qt::DisplayRole) {        if (value().isValid()) {            return value().toString();        } else {            return "####";        }    } else if (role == Qt::TextAlignmentRole) {        if (value().type() == QVariant::String) {            return int(Qt::AlignLeft | Qt::AlignVCenter);        } else {            return int(Qt::AlignRight | Qt::AlignVCenter);        }    } else {        return QTableWidgetItem::data(role);    }}void Cell::setFormula(const QString &formula){    setData(Qt::EditRole, formula);}QString Cell::formula() const{    return data(Qt::EditRole).toString();}void Cell::setDirty(){    cacheIsDirty = true;}const QVariant Invalid;QVariant Cell::value() const{    if (cacheIsDirty) {        cacheIsDirty = false;        QString formulaStr = formula();        if (formulaStr.startsWith('\'')) {            cachedValue = formulaStr.mid(1);        } else if (formulaStr.startsWith('=')) {            cachedValue = Invalid;            QString expr = formulaStr.mid(1);            expr.replace(" ", "");            expr.append(QChar::Null);            int pos = 0;            cachedValue = evalExpression(expr, pos);            if (expr[pos] != QChar::Null)                cachedValue = Invalid;        } else {            bool ok;            double d = formulaStr.toDouble(&ok);            if (ok) {                cachedValue = d;            } else {                cachedValue = formulaStr;            }        }    }    return cachedValue;}QVariant Cell::evalExpression(const QString &str, int &pos) const{    QVariant result = evalTerm(str, pos);    while (str[pos] != QChar::Null) {        QChar op = str[pos];        if (op != '+' && op != '-')            return result;        ++pos;        QVariant term = evalTerm(str, pos);        if (result.type() == QVariant::Double                && term.type() == QVariant::Double) {            if (op == '+') {                result = result.toDouble() + term.toDouble();            } else {                result = result.toDouble() - term.toDouble();            }        } else {            result = Invalid;        }    }    return result;}QVariant Cell::evalTerm(const QString &str, int &pos) const{    QVariant result = evalFactor(str, pos);    while (str[pos] != QChar::Null) {        QChar op = str[pos];        if (op != '*' && op != '/')            return result;        ++pos;        QVariant factor = evalFactor(str, pos);        if (result.type() == QVariant::Double                && factor.type() == QVariant::Double) {            if (op == '*') {                result = result.toDouble() * factor.toDouble();            } else {                if (factor.toDouble() == 0.0) {                    result = Invalid;                } else {                    result = result.toDouble() / factor.toDouble();                }            }        } else {            result = Invalid;        }    }    return result;}QVariant Cell::evalFactor(const QString &str, int &pos) const{    QVariant result;    bool negative = false;    if (str[pos] == '-') {        negative = true;        ++pos;    }    if (str[pos] == '(') {        ++pos;        result = evalExpression(str, pos);        if (str[pos] != ')')            result = Invalid;        ++pos;    } else {        QRegExp regExp("[A-Za-z][1-9][0-9]{0,2}");        QString token;        while (str[pos].isLetterOrNumber() || str[pos] == '.') {            token += str[pos];            ++pos;        }        if (regExp.exactMatch(token)) {            int column = token[0].toUpper().unicode() - 'A';            int row = token.mid(1).toInt() - 1;            Cell *c = static_cast<Cell *>(                              tableWidget()->item(row, column));            if (c) {                result = c->value();            } else {                result = 0.0;            }        } else {            bool ok;            result = token.toDouble(&ok);            if (!ok)                result = Invalid;        }    }    if (negative) {        if (result.type() == QVariant::Double) {            result = -result.toDouble();        } else {            result = Invalid;        }    }    return result;}