sequenceelement.cpp

/* This file is part of the KDE project
   Copyright (C) 2001 Andrea Rizzi <rizzi@kde.org>
                  Ulrich Kuettler <ulrich.kuettler@mailbox.tu-dresden.de>
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
 
   This library 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
   Library General Public License for more details.
 
   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
*/
 
#include <stdlib.h>
#include <math.h>
 
#include <tqpainter.h>
#include <tqpaintdevice.h>
#include <tqvaluestack.h>
 
#include <kcommand.h>
#include <kdebug.h>
#include <tdelocale.h>
 
//#include <boost/spirit.hpp>
 
#include "MatrixDialog.h"
#include "bracketelement.h"
#include "creationstrategy.h"
#include "elementtype.h"
#include "elementvisitor.h"
#include "formulacursor.h"
#include "formulaelement.h"
#include "fractionelement.h"
#include "indexelement.h"
#include "kformulacommand.h"
#include "kformulacontainer.h"
#include "kformuladocument.h"
#include "matrixelement.h"
#include "rootelement.h"
#include "sequenceelement.h"
#include "sequenceparser.h"
#include "spaceelement.h"
#include "symbolelement.h"
#include "symboltable.h"
#include "textelement.h"
#include "numberelement.h"
#include "identifierelement.h"
#include "operatorelement.h"
 
#include <assert.h>
 
KFORMULA_NAMESPACE_BEGIN
//using namespace std;
 
ElementCreationStrategy* SequenceElement::creationStrategy = 0;
 
void SequenceElement::setCreationStrategy( ElementCreationStrategy* strategy )
{
    creationStrategy = strategy;
}
 
void SequenceElement::setStyle( StyleElement *st ) 
{
    style = st;
}
 
SequenceElement::SequenceElement(BasicElement* parent)
        : BasicElement(parent), parseTree(0), textSequence(true),singlePipe(true), style(0)
{
    assert( creationStrategy != 0 );
    children.setAutoDelete(true);
}
 
 
SequenceElement::~SequenceElement()
{
    delete parseTree;
}
 
SequenceElement::SequenceElement( const SequenceElement& other )
    : BasicElement( other )
{
    children.setAutoDelete(true);
    uint count = other.children.count();
    for (uint i = 0; i < count; i++) {
        BasicElement* child = children.at(i)->clone();
        child->setParent( this );
        children.append( child );
    }
}
 
 
bool SequenceElement::accept( ElementVisitor* visitor )
{
    return visitor->visit( this );
}
 
 
bool SequenceElement::readOnly( const FormulaCursor* ) const
{
    return getParent()->readOnly( this );
}
 
 
BasicElement* SequenceElement::goToPos( FormulaCursor* cursor, bool& handled,
                                        const LuPixelPoint& point, const LuPixelPoint& parentOrigin )
{
    BasicElement* e = BasicElement::goToPos(cursor, handled, point, parentOrigin);
    if (e != 0) {
        LuPixelPoint myPos(parentOrigin.x() + getX(),
                           parentOrigin.y() + getY());
 
        uint count = children.count();
        for (uint i = 0; i < count; i++) {
            BasicElement* child = children.at(i);
            e = child->goToPos(cursor, handled, point, myPos);
            if (e != 0) {
                if (!handled) {
                    handled = true;
                    if ((point.x() - myPos.x()) < (e->getX() + e->getWidth()*2/3)) {
                        cursor->setTo(this, children.find(e));
                    }
                    else {
                        cursor->setTo(this, children.find(e)+1);
                    }
                }
                return e;
            }
        }
 
        luPixel dx = point.x() - myPos.x();
        //int dy = point.y() - myPos.y();
 
        for (uint i = 0; i < count; i++) {
            BasicElement* child = children.at(i);
            if (dx < child->getX()) {
                cursor->setTo( this, i );
                handled = true;
                return children.at( i );
            }
        }
 
        cursor->setTo(this, countChildren());
        handled = true;
        return this;
    }
    return 0;
}
 
 
bool SequenceElement::isEmpty()
{
    uint count = children.count();
    for (uint i = 0; i < count; i++) {
        BasicElement* child = children.at(i);
        if (!child->isInvisible()) {
            return false;
        }
    }
    return true;
}
 
 
void SequenceElement::calcSizes( const ContextStyle& context,
                                 ContextStyle::TextStyle tstyle,
                                 ContextStyle::IndexStyle istyle,
                                 StyleAttributes& style )
{
    double factor = style.sizeFactor();
    if (!isEmpty()) {
        luPixel width = 0;
        luPixel toBaseline = 0;
        luPixel fromBaseline = 0;
 
        width += context.ptToPixelX( getSpaceBefore( context, tstyle, factor ) );
 
        // Let's do all normal elements that have a base line.
        TQPtrListIterator<BasicElement> it( children );
        for ( ; it.current(); ++it ) {
            BasicElement* child = it.current();
 
            if ( !child->isInvisible() ) {
                child->calcSizes( context, tstyle, istyle, style );
                child->setX( width );
                width += child->getWidth();
 
                luPixel childBaseline = child->getBaseline();
                if ( childBaseline > -1 ) {
                    toBaseline = TQMAX( toBaseline, childBaseline );
                    fromBaseline = TQMAX( fromBaseline,
                                         child->getHeight() - childBaseline );
                }
                else {
                    luPixel bl = child->getHeight()/2 + context.axisHeight( tstyle, factor );
                    toBaseline = TQMAX( toBaseline, bl );
                    fromBaseline = TQMAX( fromBaseline, child->getHeight() - bl );
                }
            }
            else {
                child->setX( width );
            }
        }
 
        width += context.ptToPixelX( getSpaceAfter( context, tstyle, factor ) );
 
        setWidth(width);
        setHeight(toBaseline+fromBaseline);
        setBaseline(toBaseline);
 
        setChildrenPositions();
    }
    else {
        luPixel w = context.getEmptyRectWidth( factor );
        luPixel h = context.getEmptyRectHeight( factor );
        setWidth( w );
        setHeight( h );
        setBaseline( h );
        //setMidline( h*.5 );
    }
}
 
 
void SequenceElement::setChildrenPositions()
{
    TQPtrListIterator<BasicElement> it( children );
    for ( ; it.current(); ++it ) {
        BasicElement* child = it.current();
        child->setY(getBaseline() - child->getBaseline());
    }
}
 
 
void SequenceElement::draw( TQPainter& painter, const LuPixelRect& r,
                            const ContextStyle& context,
                            ContextStyle::TextStyle tstyle,
                            ContextStyle::IndexStyle istyle,
                            StyleAttributes& style,
                            const LuPixelPoint& parentOrigin )
{
    LuPixelPoint myPos( parentOrigin.x() + getX(), parentOrigin.y() + getY() );
    // There might be zero sized elements that still want to be drawn at least
    // in edit mode. (EmptyElement)
    //if ( !LuPixelRect( myPos.x(), myPos.y(), getWidth(), getHeight() ).intersects( r ) )
    //    return;
 
    if (!isEmpty()) {
        TQPtrListIterator<BasicElement> it( children );
        for (int i = 0 ; it.current(); i++) {
            BasicElement* child = it.current();
            if (!child->isInvisible()) {
                child->draw(painter, r, context, tstyle, istyle, style, myPos);
 
                // Each starting element draws the whole token
                // This only concerns TextElements.
                /*
                ElementType* token = child->getElementType();
                if ( token != 0 ) {
                    it += token->end() - token->start();
                }
                else {
                    ++it;
                }
                */
            }
//            else {
                ++it;
//            }
        }
    }
    else {
        drawEmptyRect( painter, context, style.sizeFactor(), myPos );
    }
    // Debug
    //painter.setPen(TQt::green);
    //painter.drawRect(parentOrigin.x() + getX(), parentOrigin.y() + getY(),
    //                 getWidth(), getHeight());
//     painter.drawLine( context.layoutUnitToPixelX( parentOrigin.x() + getX() ),
//                       context.layoutUnitToPixelY( parentOrigin.y() + getY() + axis( context, tstyle ) ),
//                       context.layoutUnitToPixelX( parentOrigin.x() + getX() + getWidth() ),
//                       context.layoutUnitToPixelY( parentOrigin.y() + getY() + axis( context, tstyle ) ) );
//     painter.setPen(TQt::red);
//     painter.drawLine( context.layoutUnitToPixelX( parentOrigin.x() + getX() ),
//                       context.layoutUnitToPixelY( parentOrigin.y() + getY() + getBaseline() ),
//                       context.layoutUnitToPixelX( parentOrigin.x() + getX() + getWidth() ),
//                       context.layoutUnitToPixelY( parentOrigin.y() + getY() + getBaseline() ) );
}
 
 
void SequenceElement::dispatchFontCommand( FontCommand* cmd )
{
    TQPtrListIterator<BasicElement> it( children );
    for ( ; it.current(); ++it ) {
        BasicElement* child = it.current();
        child->dispatchFontCommand( cmd );
    }
}
 
 
void SequenceElement::drawEmptyRect( TQPainter& painter, const ContextStyle& context,
                                     double factor, const LuPixelPoint& upperLeft )
{
    if ( context.edit() ) {
        painter.setBrush(TQt::NoBrush);
        painter.setPen( TQPen( context.getEmptyColor(),
                              context.layoutUnitToPixelX( context.getLineWidth( factor ) ) ) );
        painter.drawRect( context.layoutUnitToPixelX( upperLeft.x() ),
                          context.layoutUnitToPixelY( upperLeft.y() ),
                          context.layoutUnitToPixelX( getWidth() ),
                          context.layoutUnitToPixelY( getHeight() ) );
    }
}
 
void SequenceElement::calcCursorSize( const ContextStyle& context,
                                      FormulaCursor* cursor, bool smallCursor )
{
    LuPixelPoint point = widgetPos();
    uint pos = cursor->getPos();
 
    luPixel posX = getChildPosition( context, pos );
    luPixel height = getHeight();
 
    luPixel unitX = context.ptToLayoutUnitPixX( 1 );
    luPixel unitY = context.ptToLayoutUnitPixY( 1 );
 
    // Here are those evil constants that describe the cursor size.
 
    if ( cursor->isSelection() ) {
        uint mark = cursor->getMark();
        luPixel markX = getChildPosition( context, mark );
        luPixel x = TQMIN(posX, markX);
        luPixel width = abs(posX - markX);
 
        if ( smallCursor ) {
            cursor->cursorSize.setRect( point.x()+x, point.y(), width, height );
        }
        else {
            cursor->cursorSize.setRect( point.x()+x, point.y() - 2*unitY,
                                        width + unitX, height + 4*unitY );
        }
    }
    else {
        if ( smallCursor ) {
            cursor->cursorSize.setRect( point.x()+posX, point.y(),
                                        unitX, height );
        }
        else {
            cursor->cursorSize.setRect( point.x(), point.y() - 2*unitY,
                                        getWidth() + unitX, height + 4*unitY );
        }
    }
 
    cursor->cursorPoint.setX( point.x()+posX );
    cursor->cursorPoint.setY( point.y()+getHeight()/2 );
}
 
 
void SequenceElement::drawCursor( TQPainter& painter, const ContextStyle& context,
                                  StyleAttributes& style, FormulaCursor* cursor,
                                  bool smallCursor, bool activeCursor )
{
    painter.setRasterOp( TQt::XorROP );
    if ( cursor->isSelection() ) {
        const LuPixelRect& r = cursor->cursorSize;
        painter.fillRect( context.layoutUnitToPixelX( r.x() ),
                          context.layoutUnitToPixelY( r.y() ),
                          context.layoutUnitToPixelX( r.width() ),
                          context.layoutUnitToPixelY( r.height() ),
                          TQt::white );
    }
    painter.setPen( TQPen( TQt::white,
                          context.layoutUnitToPixelX( context.getLineWidth( style.sizeFactor() )/2 ) ) );
    const LuPixelPoint& point = cursor->getCursorPoint();
    const LuPixelRect& size = cursor->getCursorSize();
    if ( activeCursor )
    {
        int offset = 0;
        if ( cursor->isSelection() && cursor->getPos() > cursor->getMark() )
            offset = -1;
        painter.drawLine( context.layoutUnitToPixelX( point.x() ) + offset,
                          context.layoutUnitToPixelY( size.top() ),
                          context.layoutUnitToPixelX( point.x() ) + offset,
                          context.layoutUnitToPixelY( size.bottom() )-1 );
        painter.drawLine( context.layoutUnitToPixelX( point.x() ) + offset + 1,
                          context.layoutUnitToPixelY( size.top() ),
                          context.layoutUnitToPixelX( point.x() ) + offset + 1,
                          context.layoutUnitToPixelY( size.bottom() )-1 );
    }
    if ( !smallCursor && !cursor->isSelection() )
        painter.drawLine( context.layoutUnitToPixelX( size.left() ),
                          context.layoutUnitToPixelY( size.bottom() )-1,
                          context.layoutUnitToPixelX( size.right() )-1,
                          context.layoutUnitToPixelY( size.bottom() )-1 );
    // This might be wrong but probably isn't.
    painter.setRasterOp( TQt::CopyROP );
}
 
 
luPixel SequenceElement::getChildPosition( const ContextStyle& context, uint child )
{
    if (child < children.count()) {
        return children.at(child)->getX();
    }
    else {
        if (children.count() > 0) {
            return children.at(child-1)->getX() + children.at(child-1)->getWidth();
        }
        else {
            return context.ptToLayoutUnitPixX( 2 );
        }
    }
}
 
 
// navigation
//
// The elements are responsible to handle cursor movement themselves.
// To do this they need to know the direction the cursor moves and
// the element it comes from.
//
// The cursor might be in normal or in selection mode.
 
void SequenceElement::moveLeft(FormulaCursor* cursor, BasicElement* from)
{
    // Our parent asks us for a cursor position. Found.
    if (from == getParent()) {
        cursor->setTo(this, children.count());
        if ( cursor->isSelectionMode() ) {
            cursor->setMark( children.count() );
        }
        from->entered( this );
    }
 
    // We already owned the cursor. Ask next child then.
    else if (from == this) {
        if (cursor->getPos() > 0) {
            cursor->setTo(this, cursor->getPos()-1);
 
            // invisible elements are not visible so we move on.
            if (children.at(cursor->getPos())->isInvisible()) {
                moveLeft(cursor, this);
            }
        }
        else {
            // Needed because FormulaElement derives this.
            if (getParent() != 0) {
                getParent()->moveLeft(cursor, this);
            }
            else {
                formula()->moveOutLeft( cursor );
            }
        }
    }
 
    // The cursor came from one of our children or
    // something is wrong.
    else {
        int fromPos = children.find(from);
        if ( fromPos > 0 ) {
            children.at( fromPos - 1)->moveLeft( cursor, this );
        }
 
        // invisible elements are not visible so we move on.
        if (from->isInvisible()) {
            moveLeft(cursor, this);
        }
        formula()->tell( "" );
    }
}
 
void SequenceElement::moveRight(FormulaCursor* cursor, BasicElement* from)
{
    // Our parent asks us for a cursor position. Found.
    if (from == getParent()) {
        cursor->setTo(this, 0);
        from->entered( this );
    }
 
    // We already owned the cursor. Ask next child then.
    else if (from == this) {
        uint pos = cursor->getPos();
        if (pos < children.count()) {
            cursor->setTo(this, pos+1);
            
            // invisible elements are not visible so we move on.
            if (children.at(pos)->isInvisible()) {
                moveRight(cursor, this);
            }
        }
        else {
            // Needed because FormulaElement derives this.
            if (getParent() != 0) {
                getParent()->moveRight(cursor, this);
            }
            else {
                formula()->moveOutRight( cursor );
            }
        }
    }
 
    // The cursor came from one of our children or
    // something is wrong.
    else {
        int fromPos = children.find(from);
        if ( fromPos < children.count() - 1 ) {
            children.at( fromPos + 1 )->moveDown( cursor, this );
        }
        else {
            cursor->setTo(this, fromPos+1);
        }
        if (cursor->isSelectionMode()) {
            cursor->setMark(fromPos);
        }
 
        // invisible elements are not visible so we move on.
        if (from->isInvisible()) {
            moveRight(cursor, this);
        }
        formula()->tell( "" );
    }
}
 
 
void SequenceElement::moveWordLeft(FormulaCursor* cursor)
{
    uint pos = cursor->getPos();
    if (pos > 0) {
        ElementType* type = children.at(pos-1)->getElementType();
        if (type != 0) {
            cursor->setTo(this, type->start());
        }
    }
    else {
        moveLeft(cursor, this);
    }
}
 
 
void SequenceElement::moveWordRight(FormulaCursor* cursor)
{
    uint pos = cursor->getPos();
    if (pos < children.count()) {
        ElementType* type = children.at(pos)->getElementType();
        if (type != 0) {
            cursor->setTo(this, type->end());
        }
    }
    else {
        moveRight(cursor, this);
    }
}
 
 
void SequenceElement::moveUp(FormulaCursor* cursor, BasicElement* from)
{
    if (from == getParent()) {
        moveRight(cursor, this);
    }
    else if ( from == this ) {
        if ( getParent() != 0 ) {
            uint pos = cursor->getPos();
            if ( pos < (children.count() - 1) / 2 ) {
                getParent()->moveLeft( cursor, this );
            }
            else {
                getParent()->moveRight( cursor, this );
            }
        }
        else {
                formula()->moveOutAbove( cursor );
        }
    }
    else {
        if (getParent() != 0) {
            getParent()->moveUp(cursor, this);
        }
        else {
            formula()->moveOutAbove( cursor );
        }
    }
}
 
void SequenceElement::moveDown(FormulaCursor* cursor, BasicElement* from)
{
    if (from == getParent()) {
        cursor->setTo(this, 0);
        from->entered( this );
    }
    else if (from == this) {
        uint pos = cursor->getPos();
        if (pos < children.count()) {
                children.at(pos)->moveDown(cursor, this);
        }
    }
    else {
        if (getParent() != 0) {
            getParent()->moveDown(cursor, this);
        }
        else {
            cursor->setTo( this, children.count() );
            from->entered( this );
//            formula()->moveOutBelow( cursor );
        }
    }
}
 
void SequenceElement::moveHome(FormulaCursor* cursor)
{
    if (cursor->isSelectionMode()) {
        BasicElement* element = cursor->getElement();
        if (element != this) {
            while (element->getParent() != this) {
                element = element->getParent();
            }
            cursor->setMark(children.find(element)+1);
        }
    }
    cursor->setTo(this, 0);
}
 
void SequenceElement::moveEnd(FormulaCursor* cursor)
{
    if (cursor->isSelectionMode()) {
        BasicElement* element = cursor->getElement();
        if (element != this) {
            while (element->getParent() != this) {
                element = element->getParent();
                if (element == 0) {
                    cursor->setMark(children.count());
                    break;
                }
            }
            if (element != 0) {
                cursor->setMark(children.find(element));
            }
        }
    }
    cursor->setTo(this, children.count());
}
 
void SequenceElement::goInside(FormulaCursor* cursor)
{
    cursor->setSelection(false);
    cursor->setTo(this, 0);
}
 
void SequenceElement::goInsideLast(FormulaCursor* cursor)
{
    cursor->setSelection(false);
    cursor->setTo(this, children.count());
}
 
 
// children
 
bool SequenceElement::insert( uint index, BasicElement *child )
{
    return children.insert( index, child );
}
 
// void SequenceElement::removeChild(FormulaCursor* cursor, BasicElement* child)
// {
//     int pos = children.find(child);
//     formula()->elementRemoval(child, pos);
//     cursor->setTo(this, pos);
//     children.remove(pos);
//     /*
//         if len(self.children) == 0:
//             if self.parent != None:
//                 self.parent.removeChild(cursor, self)
//                 return
//     */
//     formula()->changed();
// }
 
 
void SequenceElement::insert(FormulaCursor* cursor,
                             TQPtrList<BasicElement>& newChildren,
                             Direction direction)
{
    int pos = cursor->getPos();
    uint count = newChildren.count();
    for (uint i = 0; i < count; i++) {
        BasicElement* child = newChildren.take(0);
        child->setParent(this);
        children.insert(pos+i, child);
    }
    if (direction == beforeCursor) {
        cursor->setTo(this, pos+count, pos);
    }
    else {
        cursor->setTo(this, pos, pos+count);
    }
 
    formula()->changed();
    parse();
}
 
 
void SequenceElement::remove(FormulaCursor* cursor,
                             TQPtrList<BasicElement>& removedChildren,
                             Direction direction)
{
    if (cursor->isSelection()) {
        int from = cursor->getSelectionStart();
        int to = cursor->getSelectionEnd();
        for (int i = from; i < to; i++) {
            removeChild(removedChildren, from);
        }
        cursor->setTo(this, from);
        cursor->setSelection(false);
    }
    else {
        if (direction == beforeCursor) {
            int pos = cursor->getPos() - 1;
            if (pos >= 0) {
                while (pos >= 0) {
                    BasicElement* child = children.at(pos);
                    formula()->elementRemoval(child);
                    children.take(pos);
                    removedChildren.prepend(child);
                    if (!child->isInvisible()) {
                        break;
                    }
                    pos--;
                }
                cursor->setTo(this, pos);
                formula()->changed();
            }
        }
        else {
            uint pos = cursor->getPos();
            if (pos < children.count()) {
                while (pos < children.count()) {
                    BasicElement* child = children.at(pos);
                    formula()->elementRemoval(child);
                    children.take(pos);
                    removedChildren.append(child);
                    if (!child->isInvisible()) {
                        break;
                    }
                }
                // It is necessary to set the cursor to its old
                // position because it got a notification and
                // moved to the beginning of this sequence.
                cursor->setTo(this, pos);
                formula()->changed();
            }
        }
    }
    parse();
}
 
 
void SequenceElement::removeChild(TQPtrList<BasicElement>& removedChildren, int pos)
{
    BasicElement* child = children.at(pos);
    formula()->elementRemoval(child);
    children.take(pos);
    removedChildren.append(child);
    //cerr << *removedChildren.at(0) << endl;
    formula()->changed();
}
 
 
void SequenceElement::normalize(FormulaCursor* cursor, Direction)
{
    cursor->setSelection(false);
}
 
 
BasicElement* SequenceElement::getChild( FormulaCursor* cursor, Direction direction )
{
    if ( direction == beforeCursor ) {
        if ( cursor->getPos() > 0 ) {
            return children.at( cursor->getPos() - 1 );
        }
    }
    else {
        if ( cursor->getPos() < tqRound( children.count() ) ) {
            return children.at( cursor->getPos() );
        }
    }
    return 0;
}
 
 
void SequenceElement::selectChild(FormulaCursor* cursor, BasicElement* child)
{
    int pos = children.find(child);
    if (pos > -1) {
        cursor->setTo(this, pos+1, pos);
    }
}
 
void SequenceElement::childWillVanish(FormulaCursor* cursor, BasicElement* child)
{
    int childPos = children.find(child);
    if (childPos > -1) {
        int pos = cursor->getPos();
        if (pos > childPos) {
            pos--;
        }
        int mark = cursor->getMark();
        if (mark > childPos) {
            mark--;
        }
        cursor->setTo(this, pos, mark);
    }
}
 
 
void SequenceElement::selectAllChildren(FormulaCursor* cursor)
{
    cursor->setTo(this, children.count(), 0);
}
 
bool SequenceElement::onlyTextSelected( FormulaCursor* cursor )
{
    if ( cursor->isSelection() ) {
        uint from = TQMIN( cursor->getPos(), cursor->getMark() );
        uint to = TQMAX( cursor->getPos(), cursor->getMark() );
        for ( uint i = from; i < to; i++ ) {
            BasicElement* element = getChild( i );
            if ( element->getCharacter() == TQChar::null ) {
                return false;
            }
        }
    }
    return true;
}
 
 
KCommand* SequenceElement::buildCommand( Container* container, Request* request )
{
    FormulaCursor* cursor = container->activeCursor();
    if ( cursor->isReadOnly() ) {
        formula()->tell( i18n( "write protection" ) );
        return 0;
    }
 
    switch ( *request ) {
    case req_addText: {
        KFCReplaceToken* command = new KFCReplaceToken( i18n("Add Text"), container );
        TextRequest* tr = static_cast<TextRequest*>( request );
        IdentifierElement* id = creationStrategy->createIdentifierElement();
        command->addToken( id );
        for ( uint i = 0; i < tr->text().length(); i++ ) {
            TextElement* text = creationStrategy->createTextElement( tr->text()[i] );
            command->addContent( id, text );
        }
        return command;
    }
    case req_addTextChar: {
        KFCReplaceToken* command = new KFCReplaceToken( i18n("Add Text"), container );
        TextCharRequest* tr = static_cast<TextCharRequest*>( request );
        IdentifierElement* id = creationStrategy->createIdentifierElement();
        TextElement* text = creationStrategy->createTextElement( tr->ch() );
        command->addToken( id );
        command->addContent( id, text );
        return command;
    }
 
    case req_addOperator: {
        KFCReplaceToken* command = new KFCReplaceToken( i18n("Add Operator"), container );
        OperatorRequest* opr = static_cast<OperatorRequest*>( request );
        OperatorElement* op = creationStrategy->createOperatorElement();
        TextElement* text = creationStrategy->createTextElement( opr->ch() );
        command->addToken( op );
        command->addContent( op, text );
        return command;
    }
 
    case req_addNumber: {
        KFCReplaceToken* command = new KFCReplaceToken( i18n("Add Number"), container );
        NumberRequest* nr = static_cast<NumberRequest*>( request );
        NumberElement* num = creationStrategy->createNumberElement();
        num->setParent( this );
        TextElement* text = creationStrategy->createTextElement( nr->ch() );
        text->setParent( num );
        command->addToken( num );
        command->addContent( num, text );
        return command;
    }
 
    case req_addEmptyBox: {
        EmptyElement* element = creationStrategy->createEmptyElement();
        if ( element != 0 ) {
            KFCReplace* command = new KFCReplace( i18n("Add Empty Box"), container );
            command->addElement( element );
            return command;
        }
        break;
    }
    case req_addNameSequence:
        if ( onlyTextSelected( container->activeCursor() ) ) {
            NameSequence* nameSequence = creationStrategy->createNameSequence();
            if ( nameSequence != 0 ) {
                KFCAddReplacing* command = new KFCAddReplacing( i18n( "Add Name" ), container );
                command->setElement( nameSequence );
                return command;
            }
        }
        break;
    case req_addBracket: {
        BracketRequest* br = static_cast<BracketRequest*>( request );
        BracketElement* bracketElement =
            creationStrategy->createBracketElement( br->left(), br->right() );
        if ( bracketElement != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing(i18n("Add Bracket"), container);
            command->setElement( bracketElement );
            return command;
        }
        break;
    }
    case req_addOverline: {
        OverlineElement* overline = creationStrategy->createOverlineElement();
        if ( overline != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing(i18n("Add Overline"), container);
            command->setElement( overline );
            return command;
        }
        break;
    }
    case req_addUnderline: {
        UnderlineElement* underline = creationStrategy->createUnderlineElement();
        if ( underline != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing(i18n("Add Underline"), container);
            command->setElement( underline );
            return command;
        }
        break;
    }
    case req_addMultiline: {
        MultilineElement* multiline = creationStrategy->createMultilineElement();
        if ( multiline != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing(i18n("Add Multiline"), container);
            command->setElement( multiline );
            return command;
        }
        break;
    }
    case req_addSpace: {
        SpaceRequest* sr = static_cast<SpaceRequest*>( request );
        SpaceElement* element = creationStrategy->createSpaceElement( sr->space() );
        if ( element != 0 ) {
            KFCReplace* command = new KFCReplace( i18n("Add Space"), container );
            command->addElement( element );
            return command;
        }
        break;
    }
    case req_addFraction: {
        FractionElement* fraction = creationStrategy->createFractionElement();
        if ( fraction != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing(i18n("Add Fraction"), container);
            command->setElement( fraction );
            return command;
        }
        break;
    }
    case req_addRoot: {
        RootElement* root = creationStrategy->createRootElement();
        if ( root != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing(i18n("Add Root"), container);
            command->setElement( root );
            return command;
        }
        break;
    }
    case req_addSymbol: {
        SymbolRequest* sr = static_cast<SymbolRequest*>( request );
        SymbolElement* symbol = creationStrategy->createSymbolElement( sr->type() );
        if ( symbol != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing( i18n( "Add Symbol" ), container );
            command->setElement( symbol );
            return command;
        }
        break;
    }
    case req_addOneByTwoMatrix: {
        FractionElement* element = creationStrategy->createFractionElement();
        if ( element != 0 ) {
            KFCAddReplacing* command = new KFCAddReplacing( i18n("Add 1x2 Matrix"), container );
            element->showLine(false);
            command->setElement(element);
            return command;
        }
    }
    case req_addMatrix: {
        MatrixRequest* mr = static_cast<MatrixRequest*>( request );
        uint rows = mr->rows(), cols = mr->columns();
        if ( ( rows == 0 ) || ( cols == 0 ) ) {
            MatrixDialog* dialog = new MatrixDialog( 0 );
            if ( dialog->exec() ) {
                rows = dialog->h;
                cols = dialog->w;
            }
            delete dialog;
        }
 
        if ( ( rows != 0 ) && ( cols != 0 ) ) {
            KFCAddReplacing* command = new KFCAddReplacing( i18n( "Add Matrix" ), container );
            command->setElement( creationStrategy->createMatrixElement( rows, cols ) );
            return command;
        }
        else
            return 0L;
    }
    case req_addIndex: {
        if ( cursor->getPos() > 0 && !cursor->isSelection() ) {
            IndexElement* element =
                dynamic_cast<IndexElement*>( children.at( cursor->getPos()-1 ) );
            if ( element != 0 ) {
                element->goInside( cursor );
                return element->buildCommand( container, request );
            }
        }
        IndexElement* element = creationStrategy->createIndexElement();
        if ( element != 0 ) {
            if ( !cursor->isSelection() ) {
                cursor->moveLeft( SelectMovement | WordMovement );
            }
            IndexRequest* ir = static_cast<IndexRequest*>( request );
            KFCAddIndex* command = new KFCAddIndex( container, element,
                                                    element->getIndex( ir->index() ) );
            return command;
        }
        break;
    }
    case req_removeEnclosing: {
        if ( !cursor->isSelection() ) {
            DirectedRemove* dr = static_cast<DirectedRemove*>( request );
            KFCRemoveEnclosing* command = new KFCRemoveEnclosing( container, dr->direction() );
            return command;
        }
    }
    case req_remove: {
        SequenceElement* sequence = cursor->normal();
        if ( sequence &&
             ( sequence == sequence->formula() ) &&
             ( sequence->countChildren() == 0 ) ) {
            sequence->formula()->removeFormula( cursor );
            return 0;
        }
        else {
            DirectedRemove* dr = static_cast<DirectedRemove*>( request );
 
            // empty removes are not legal!
            if ( !cursor->isSelection() ) {
                if ( countChildren() > 0 ) {
                    if ( ( cursor->getPos() == 0 ) && ( dr->direction() == beforeCursor ) ) {
                        return 0;
                    }
                    if ( ( cursor->getPos() == countChildren() ) && ( dr->direction() == afterCursor ) ) {
                        return 0;
                    }
                }
                else if ( getParent() == 0 ) {
                    return 0;
                }
            }
 
            KFCRemove* command = new KFCRemove( container, dr->direction() );
            return command;
        }
    }
    case req_compactExpression: {
        cursor->moveEnd();
        cursor->moveRight();
        formula()->cursorHasMoved( cursor );
        break;
    }
    case req_makeGreek: {
        TextElement* element = cursor->getActiveTextElement();
        if ((element != 0) && !element->isSymbol()) {
            cursor->selectActiveElement();
            const SymbolTable& table = container->document()->getSymbolTable();
            if (table.greekLetters().find(element->getCharacter()) != -1) {
                KFCReplace* command = new KFCReplace( i18n( "Change Char to Symbol" ), container );
                TextElement* symbol = creationStrategy->createTextElement( table.unicodeFromSymbolFont( element->getCharacter() ), true );
                command->addElement( symbol );
                return command;
            }
            cursor->setSelection( false );
        }
        break;
    }
    case req_paste:
    case req_copy:
    case req_cut:
        break;
    case req_formatBold:
    case req_formatItalic: {
        if ( cursor->isSelection() ) {
            CharStyleRequest* csr = static_cast<CharStyleRequest*>( request );
            CharStyle cs = normalChar;
            if ( csr->bold() ) cs = static_cast<CharStyle>( cs | boldChar );
            if ( csr->italic() ) cs = static_cast<CharStyle>( cs | italicChar );
            CharStyleCommand* cmd = new CharStyleCommand( cs, i18n( "Change Char Style" ), container );
            int end = cursor->getSelectionEnd();
            for ( int i = cursor->getSelectionStart(); i<end; ++i ) {
                cmd->addElement( children.at( i ) );
            }
            return cmd;
        }
        break;
    }
    case req_formatFamily: {
        if ( cursor->isSelection() ) {
            CharFamilyRequest* cfr = static_cast<CharFamilyRequest*>( request );
            CharFamily cf = cfr->charFamily();
            CharFamilyCommand* cmd = new CharFamilyCommand( cf, i18n( "Change Char Family" ), container );
            int end = cursor->getSelectionEnd();
            for ( int i = cursor->getSelectionStart(); i<end; ++i ) {
                cmd->addElement( children.at( i ) );
            }
            return cmd;
        }
        break;
    }
    default:
        break;
    }
    return 0;
}
 
 
KCommand* SequenceElement::input( Container* container, TQKeyEvent* event )
{
    TQChar ch = event->text().at( 0 );
    if ( ch.isPrint() ) {
        return input( container, ch );
    }
    else {
        int action = event->key();
        int state = event->state();
        MoveFlag flag = movementFlag(state);
 
    switch ( action ) {
        case TQt::Key_BackSpace: {
            DirectedRemove r( req_remove, beforeCursor );
            return buildCommand( container, &r );
        }
        case TQt::Key_Delete: {
            DirectedRemove r( req_remove, afterCursor );
            return buildCommand( container, &r );
        }
    case TQt::Key_Left: {
            FormulaCursor* cursor = container->activeCursor();
            cursor->moveLeft( flag );
            formula()->cursorHasMoved( cursor );
            break;
        }
        case TQt::Key_Right: {
            FormulaCursor* cursor = container->activeCursor();
            cursor->moveRight( flag );
            formula()->cursorHasMoved( cursor );
            break;
        }
        case TQt::Key_Up: {
            FormulaCursor* cursor = container->activeCursor();
            cursor->moveUp( flag );
            formula()->cursorHasMoved( cursor );
            break;
        }
        case TQt::Key_Down: {
            FormulaCursor* cursor = container->activeCursor();
            cursor->moveDown( flag );
            formula()->cursorHasMoved( cursor );
            break;
        }
        case TQt::Key_Home: {
            FormulaCursor* cursor = container->activeCursor();
            cursor->moveHome( flag );
            formula()->cursorHasMoved( cursor );
            break;
        }
        case TQt::Key_End: {
            FormulaCursor* cursor = container->activeCursor();
            cursor->moveEnd( flag );
            formula()->cursorHasMoved( cursor );
            break;
        }
        default:
            if ( state & TQt::ControlButton ) {
                switch ( event->key() ) {
                case TQt::Key_AsciiCircum: {
                    IndexRequest r( upperLeftPos );
                    return buildCommand( container, &r );
                }
                case TQt::Key_Underscore: {
                    IndexRequest r( lowerLeftPos );
                    return buildCommand( container, &r );
                }
                default:
                    break;
                }
            }
        }
    }
    return 0;
}
 
 
KCommand* SequenceElement::input( Container* container, TQChar ch )
{
    int unicode = ch.unicode();
    switch (unicode) {
    case '(': {
        BracketRequest r( container->document()->leftBracketChar(),
                          container->document()->rightBracketChar() );
        singlePipe = true;
        return buildCommand( container, &r );
    }
    case '[': {
        BracketRequest r( LeftSquareBracket, RightSquareBracket );
        singlePipe = true;
        return buildCommand( container, &r );
    }
    case '{': {
        BracketRequest r( LeftCurlyBracket, RightCurlyBracket );
        singlePipe = true;
        return buildCommand( container, &r );
    }
    case '|': { 
        if (!singlePipe) { // We have had 2 '|' in a row so we want brackets
 
          DirectedRemove rDelete( req_remove, beforeCursor ); //Delete the previous '|' we dont need it any more
          KCommand* command = buildCommand( container, &rDelete );
          command->execute();
          
          BracketRequest rBracket( LeftLineBracket , RightLineBracket);
          singlePipe = true;  //the next '|' will be a single pipe again
          return buildCommand( container, &rBracket );    
        }
        else { // We really do only want 1 '|'
          TextCharRequest r(ch);
 
          //in case another '|' character is entered right after this one, '| |' brackets are made; see above
          singlePipe = false;
 
          return buildCommand( container, &r );   
        }
    }
    case '^': {
        IndexRequest r( upperRightPos );
        singlePipe = true;
        return buildCommand( container, &r );
    }
    case '_': {
        IndexRequest r( lowerRightPos );
        singlePipe = true;
        return buildCommand( container, &r );
    }
        /*
    case ' ': {
        Request r( req_compactExpression );
        singlePipe = true;
        return buildCommand( container, &r );
        }*/
    case '}': {
        Request r( req_addEmptyBox );
        singlePipe = true;
        return buildCommand( container, &r );
    }
    case ']':
    case ')':
        singlePipe = true; 
        break;
    case '\\': {
        Request r( req_addNameSequence );
        singlePipe = true;
        return buildCommand( container, &r );
    }
    default: {
        singlePipe = true;
        if ( ch.isPunct() || ch.isSymbol() ) {
            OperatorRequest r( ch );
            return buildCommand( container, &r );
        }
        if ( ch.isNumber() ) {
            NumberRequest r( ch );
            return buildCommand( container, &r );
        }
        TextCharRequest r( ch );
        return buildCommand( container, &r );
    }
    }
    return 0;
}
 
void SequenceElement::getChildrenDom( TQDomDocument& doc, TQDomElement elem,
                                     uint from, uint to)
{
    for (uint i = from; i < to; i++) {
        TQDomElement tmpEleDom=children.at(i)->getElementDom(doc);
        elem.appendChild(tmpEleDom);
    }
}
 
void SequenceElement::getChildrenMathMLDom( TQDomDocument& doc, TQDomNode& parent,
                                            uint from, uint to)
{
    for ( uint i = from; i < to; i++ ) {
        children.at( i )->writeMathML( doc, parent, false );
    }
}
 
 
bool SequenceElement::buildChildrenFromDom(TQPtrList<BasicElement>& list, TQDomNode n)
{
    while (!n.isNull()) {
        if (n.isElement()) {
            TQDomElement e = n.toElement();
            BasicElement* child = 0;
            TQString tag = e.tagName().upper();
 
            child = createElement(tag, e);
            if (child != 0) {
                child->setParent(this);
                if (child->buildFromDom(e)) {
                    list.append(child);
                }
                else {
                    delete child;
                    return false;
                }
            }
            else {
                return false;
            }
        }
        n = n.nextSibling();
    }
    parse();
    return true;
}
 
 
BasicElement* SequenceElement::createElement( TQString type, const TQDomElement& element )
{
    return creationStrategy->createElement( type, element );
}
 
void SequenceElement::writeDom(TQDomElement element)
{
    BasicElement::writeDom(element);
 
    uint count = children.count();
    TQDomDocument doc = element.ownerDocument();
    getChildrenDom(doc, element, 0, count);
}
 
bool SequenceElement::readAttributesFromDom(TQDomElement element)
{
    if (!BasicElement::readAttributesFromDom(element)) {
        return false;
    }
    return true;
}
 
bool SequenceElement::readContentFromDom(TQDomNode& node)
{
    if (!BasicElement::readContentFromDom(node)) {
        return false;
    }
 
    return buildChildrenFromDom(children, node);
}
 
 
void SequenceElement::parse()
{
    delete parseTree;
 
    textSequence = true;
    for (BasicElement* element = children.first();
         element != 0;
         element = children.next()) {
 
        // Those types are gone. Make sure they won't
        // be used.
        element->setElementType(0);
 
        if (element->getCharacter().isNull()) {
            textSequence = false;
        }
    }
 
    const SymbolTable& symbols = formula()->getSymbolTable();
    SequenceParser parser(symbols);
    parseTree = parser.parse(children);
 
    // With the IndexElement dynamically changing its text/non-text
    // behaviour we need to reparse your parent, too. Hacky!
    BasicElement* p = getParent();
    if ( p != 0 ) {
        SequenceElement* seq = dynamic_cast<SequenceElement*>( p->getParent() );
        if ( seq != 0 ) {
            seq->parse();
        }
    }
    // debug
    //parseTree->output();
}
 
 
bool SequenceElement::isFirstOfToken( BasicElement* child )
{
    return ( child->getElementType() != 0 ) && isChildNumber( child->getElementType()->start(), child );
}
 
 
TQString SequenceElement::toLatex()
{
    TQString content;
    uint count = children.count();
    for ( uint i = 0; i < count; i++ ) {
        BasicElement* child = children.at( i );
//         if ( isFirstOfToken( child ) ) {
//             content += "";
//         }
        content += child->toLatex();
    }
    return content;
}
 
 
TQString SequenceElement::formulaString()
{
    TQString content;
    uint count = children.count();
    for ( uint i = 0; i < count; i++ ) {
        BasicElement* child = children.at( i );
        //if ( isFirstOfToken( child ) ) {
        //    content += " ";
        //}
        content += child->formulaString();
    }
    return content;
}
 
 
void SequenceElement::writeMathMLContent( TQDomDocument& doc, TQDomElement& element, bool oasisFormat ) const
{
    for ( TQPtrListIterator<BasicElement> it( children ); it.current(); ++it ) {
        it.current()->writeMathML( doc, element, oasisFormat );
    }
}
 
 
const BasicElement* SequenceElement::getChild( uint i ) const
{
    TQPtrListIterator<BasicElement> it( children );
    it += i;
    return it.current();
}
 
 
int SequenceElement::childPos( const BasicElement* child ) const
{
    TQPtrListIterator<BasicElement> it( children );
    uint count = it.count();
    for ( uint i=0; i<count; ++i, ++it ) {
        if ( it.current() == child ) {
            return i;
        }
    }
    return -1;
}
 
 
NameSequence::NameSequence( BasicElement* parent )
    : SequenceElement( parent )
{
}
 
 
bool NameSequence::accept( ElementVisitor* visitor )
{
    return visitor->visit( this );
}
 
 
void NameSequence::calcCursorSize( const ContextStyle& context,
                                   FormulaCursor* cursor, bool smallCursor )
{
    inherited::calcCursorSize( context, cursor, smallCursor );
    LuPixelPoint point = widgetPos();
    luPixel unitX = context.ptToLayoutUnitPixX( 1 );
    luPixel unitY = context.ptToLayoutUnitPixY( 1 );
    cursor->addCursorSize( LuPixelRect( point.x()-unitX, point.y()-unitY,
                                        getWidth()+2*unitX, getHeight()+2*unitY ) );
}
 
void NameSequence::drawCursor( TQPainter& painter, const ContextStyle& context,
                               StyleAttributes& style, FormulaCursor* cursor,
                               bool smallCursor, bool activeCursor )
{
    LuPixelPoint point = widgetPos();
    painter.setPen( TQPen( context.getEmptyColor(),
                          context.layoutUnitToPixelX( context.getLineWidth( style.sizeFactor() )/2 ) ) );
    luPixel unitX = context.ptToLayoutUnitPixX( 1 );
    luPixel unitY = context.ptToLayoutUnitPixY( 1 );
    painter.drawRect( context.layoutUnitToPixelX( point.x()-unitX ),
                      context.layoutUnitToPixelY( point.y()-unitY ),
                      context.layoutUnitToPixelX( getWidth()+2*unitX ),
                      context.layoutUnitToPixelY( getHeight()+2*unitY ) );
 
    inherited::drawCursor( painter, context, style, cursor, smallCursor, activeCursor );
}
 
void NameSequence::moveWordLeft( FormulaCursor* cursor )
{
    uint pos = cursor->getPos();
    if ( pos > 0 ) {
        cursor->setTo( this, 0 );
    }
    else {
        moveLeft( cursor, this );
    }
}
 
void NameSequence::moveWordRight( FormulaCursor* cursor )
{
    int pos = cursor->getPos();
    if ( pos < countChildren() ) {
        cursor->setTo( this, countChildren() );
    }
    else {
        moveRight( cursor, this );
    }
}
 
 
KCommand* NameSequence::compactExpressionCmd( Container* container )
{
    BasicElement* element = replaceElement( container->document()->getSymbolTable() );
    if ( element != 0 ) {
        getParent()->selectChild( container->activeCursor(), this );
 
        KFCReplace* command = new KFCReplace( i18n( "Add Element" ), container );
        command->addElement( element );
        return command;
    }
    return 0;
}
 
KCommand* NameSequence::buildCommand( Container* container, Request* request )
{
    switch ( *request ) {
    case req_compactExpression:
        return compactExpressionCmd( container );
    case req_addSpace:
    case req_addIndex:
    case req_addMatrix:
    case req_addOneByTwoMatrix:
    case req_addSymbol:
    case req_addRoot:
    case req_addFraction:
    case req_addBracket:
    case req_addNameSequence:
        return 0;
    default:
        break;
    }
    return inherited::buildCommand( container, request );
}
 
 
KCommand* NameSequence::input( Container* container, TQChar ch )
{
    int unicode = ch.unicode();
    switch (unicode) {
    case '(':
    case '[':
    case '|':
    case '^':
    case '_':
    case '}':
    case ']':
    case ')':
    case '\\': {
//         KCommand* compact = compactExpressionCmd( container );
//         KCommand* cmd = static_cast<SequenceElement*>( getParent() )->input( container, ch );
//         if ( compact != 0 ) {
//             KMacroCommand* macro = new KMacroCommand( cmd->name() );
//             macro->addCommand( compact );
//             macro->addCommand( cmd );
//             return macro;
//         }
//         else {
//             return cmd;
//         }
        break;
    }
    case '{':
    case ' ': {
        Request r( req_compactExpression );
        return buildCommand( container, &r );
    }
    default: {
        TextCharRequest r( ch );
        return buildCommand( container, &r );
    }
    }
    return 0;
}
 
void NameSequence::setElementType( ElementType* t )
{
    inherited::setElementType( t );
    parse();
}
 
BasicElement* NameSequence::replaceElement( const SymbolTable& table )
{
    TQString name = buildName();
    TQChar ch = table.unicode( name );
    if ( !ch.isNull() ) {
        return new TextElement( ch, true );
    }
    else {
        ch = table.unicode( i18n( name.latin1() ) );
        if ( !ch.isNull() ) {
            return new TextElement( ch, true );
        }
    }
 
    if ( name == "!" )    return new SpaceElement( NEGTHIN );
    if ( name == "," )    return new SpaceElement( THIN );
    if ( name == ">" )    return new SpaceElement( MEDIUM );
    if ( name == ";" )    return new SpaceElement( THICK );
    if ( name == "quad" ) return new SpaceElement( QUAD );
 
    if ( name == "frac" ) return new FractionElement();
    if ( name == "atop" ) {
        FractionElement* frac = new FractionElement();
        frac->showLine( false );
        return frac;
    }
    if ( name == "sqrt" ) return new RootElement();
 
    return 0;
}
 
BasicElement* NameSequence::createElement( TQString type )
{
    if      ( type == "TEXT" )         return new TextElement();
    return 0;
}
 
// void NameSequence::parse()
// {
//     // A name sequence is known as name and so are its children.
//     // Caution: this is fake!
//     for ( int i = 0; i < countChildren(); i++ ) {
//         getChild( i )->setElementType( getElementType() );
//     }
// }
 
TQString NameSequence::buildName()
{
    TQString name;
    for ( uint i = 0; i < countChildren(); i++ ) {
        name += getChild( i )->getCharacter();
    }
    return name;
}
 
bool NameSequence::isValidSelection( FormulaCursor* cursor )
{
    SequenceElement* sequence = cursor->normal();
    if ( sequence == 0 ) {
        return false;
    }
    return sequence->onlyTextSelected( cursor );
}
 
int SequenceElement::buildChildrenFromMathMLDom(TQPtrList<BasicElement>& list, TQDomNode n) 
{
    while (!n.isNull()) {
        int nodeNumber = 1;
        if (n.isElement()) {
            TQDomElement e = n.toElement();
            BasicElement* child = 0;
            TQString tag = e.tagName().lower();
 
            kdDebug( DEBUGID ) << "Sequence Tag: " << tag << endl;
            if ( tag == "semantics" ) { // Special case, just pick the first child
                TQDomNode node = e.firstChild();
                while( ! node.isElement() ) {
                    node = node.nextSibling();
                    if ( node.isNull() ) {
                        return -1;
                    }
                }
                e = node.toElement();
                tag = e.tagName().lower();
            }
            child = creationStrategy->createElement(tag, e);
            if (child != 0) {
                child->setParent(this);
                if (style != 0) {
                    child->setStyle(style);
                }
                nodeNumber = child->buildFromMathMLDom( e );
                if ( nodeNumber != -1 ) {
                    list.append(child);
                }
                else {
                    delete child;
                    return -1;
                }
            }
            else {
                kdWarning() << "Unsupported MathML element: " << tag << endl;
            }
        }
        for (int i = 0; i < nodeNumber; i++ ) {
            if ( n.isNull() ) {
                return -1;
            }
            n = n.nextSibling();
        }
    }
    // Operator elements inside a sequence have to be parsed to get proper form
    // value. Form value is needed to access operator dictionary and has to be
    // obtained after sequence parsing since its value depends on position
    // inside the sequence.
 
    // If the sequence contains more than one element, if the first or last
    // element are operators, they have to be marked differently
    if ( list.count() > 1 ) {
        if ( list.getFirst()->getElementName() == "mo" ) {
            static_cast<OperatorElement*>( list.getFirst() )->setForm( PrefixForm );
        }
        if ( list.getLast()->getElementName() == "mo" ) {
            static_cast<OperatorElement*>( list.getLast() )->setForm( PostfixForm );
        }
        for ( uint i = 1; i < list.count() - 1; i++ ) {
            if ( list.at( i )->getElementName() == "mo" ) {
                static_cast<OperatorElement*>( list.at( i ) )->setForm( InfixForm );
            }
        }
    }
    else if ( list.count() == 1 ) {
        if ( list.getFirst()->getElementName() == "mo" ) {
            static_cast<OperatorElement*>( list.getFirst() )->setForm( InfixForm );
        }
    }
    parse();
    return 1;
}
 
int SequenceElement::readContentFromMathMLDom(TQDomNode& node)
{
    if ( BasicElement::readContentFromMathMLDom(node) == -1 ) {
        return -1;
    }
 
    return buildChildrenFromMathMLDom(children, node);
}
 
int SequenceElement::buildMathMLChild( TQDomNode node )
{
    int nodeCounter = 1;
    while ( ! node.isElement() ) {
        node = node.nextSibling();
        nodeCounter++;
        if ( node.isNull() ) {
            return -1;
        }
    }
    TQDomElement e = node.toElement();
    BasicElement* child = 0;
    TQString tag = e.tagName().lower();
 
    child = creationStrategy->createElement(tag, e);
    if (child != 0) {
        child->setParent(this);
        if (style != 0) {
            child->setStyle(style);
        }
        if (child->buildFromMathMLDom(e) != -1) {
            children.append(child);
        }
        else {
            delete child;
            return -1;
        }
    }
    else {
        return -1;
    }
    parse();
    return nodeCounter;
}
 
 
 
KFORMULA_NAMESPACE_END