QPatternist::OperandsIterator Class Reference

A helper class that iterates a tree of Expression instances. It is not a sub-class of QAbstractXmlForwardIterator. More...

#include <qoperandsiterator_p.h>

Public Types
enum	TreatParent { ExcludeParent, IncludeParent }

Public Functions
Expression::Ptr	next ()
	Returns the current Expression and advances the iterator. More...
	OperandsIterator (const Expression::Ptr &start, const TreatParent treatParent)
Expression::Ptr	skipOperands ()

Private Types
typedef QPair< Expression::List, int >	Level

Properties
QStack< Level >	m_exprs

Detailed Description

A helper class that iterates a tree of Expression instances. It is not a sub-class of QAbstractXmlForwardIterator.

The OperandsIterator delivers all Expression instances that are children at any depth of the Expression passed in the constructor. The order is delivered in a defined way, from left to right and depth first.

Author

Frans Englich frans.nosp@m..eng.nosp@m.lich@.nosp@m.noki.nosp@m.a.com

Definition at line 77 of file qoperandsiterator_p.h.

Typedefs

Level

typedef QPair<Expression::List, int> QPatternist::OperandsIterator::Level

private

The second value, the int, is the current position in the first.

Definition at line 82 of file qoperandsiterator_p.h.

Enumerations

TreatParent

enum QPatternist::OperandsIterator::TreatParent

Enumerator
ExcludeParent
IncludeParent

Definition at line 85 of file qoperandsiterator_p.h.

        {
            ExcludeParent,
            IncludeParent
        };

Constructors and Destructors

OperandsIterator()

QPatternist::OperandsIterator::OperandsIterator ( const Expression::Ptr &  start, const TreatParent  treatParent  )

inline

if treatParent is IncludeParent, start is excluded.

start must be a valid Expression.

Definition at line 96 of file qoperandsiterator_p.h.

        {
            Q_ASSERT(start);
            if(treatParent == IncludeParent)
            {
                Expression::List l;
                l.append(start);
                m_exprs.push(qMakePair(l, -1));
            }

            m_exprs.push(qMakePair(start->operands(), -1));
        }

Functions

next()

Expression::Ptr QPatternist::OperandsIterator::next ( )

inline

Returns the current Expression and advances the iterator.

If the end has been reached, a default constructed pointer is returned.

We intentionally return by reference.

Definition at line 118 of file qoperandsiterator_p.h.

Referenced by QPatternist::Expression::dependencies(), QPatternist::ExpressionFactory::registerLastPath(), skipOperands(), and QPatternist::EvaluationCache< IsForGlobal >::typeCheck().

        {
            if(m_exprs.isEmpty())
                return Expression::Ptr();

            Level &lvl = m_exprs.top();
            ++lvl.second;

            if(lvl.second == lvl.first.size())
            {
                /* Resume iteration above us. */
                m_exprs.pop();

                if(m_exprs.isEmpty())
                    return Expression::Ptr();

                while(true)
                {
                    Level &previous = m_exprs.top();
                    ++previous.second;

                    if(previous.second < previous.first.count())
                    {
                        const Expression::Ptr &op = previous.first.at(previous.second);
                        m_exprs.push(qMakePair(op->operands(), -1));
                        return op;
                    }
                    else
                    {
                        // We have already reached the end of this level.
                        m_exprs.pop();
                        if(m_exprs.isEmpty())
                            return Expression::Ptr();
                    }
                }
            }
            else
            {
                const Expression::Ptr &op = lvl.first.at(lvl.second);
                m_exprs.push(qMakePair(op->operands(), -1));
                return op;
            }
        }

skipOperands()

Expression::Ptr QPatternist::OperandsIterator::skipOperands ( )

inline

Advances this iterator by the current expression and its operands.

Definition at line 165 of file qoperandsiterator_p.h.

Referenced by QPatternist::ExpressionFactory::registerLastPath().

        {
            if(m_exprs.isEmpty())
                return Expression::Ptr();

            Level &lvl = m_exprs.top();
            ++lvl.second;

            if(lvl.second == lvl.first.size())
            {
                /* We've reached the end of this level, at least. */
                m_exprs.pop();
            }

            return next();
        }

Properties

m_exprs

QStack<Level> QPatternist::OperandsIterator::m_exprs

private

Definition at line 185 of file qoperandsiterator_p.h.

Referenced by next(), OperandsIterator(), and skipOperands().

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The documentation for this class was generated from the following file:

• /src/xmlpatterns/expr/qoperandsiterator_p.h