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#include "qcommonsequencetypes_p.h" | |
#include "qemptysequence_p.h" | |
#include "qgenericsequencetype_p.h" | |
#include "qitemmappingiterator_p.h" | |
#include "qoptimizationpasses_p.h" | |
#include "qsequencemappingiterator_p.h" | |
#include "qforclause_p.h" | |
QT_BEGIN_NAMESPACE | |
using namespace QPatternist; | |
ForClause::ForClause(const VariableSlotID varSlot, | |
const Expression::Ptr &bindingSequence, | |
const Expression::Ptr &returnExpression, | |
const VariableSlotID positionSlot) : PairContainer(bindingSequence, returnExpression), | |
m_varSlot(varSlot), | |
m_positionSlot(positionSlot), | |
m_allowsMany(true) | |
{ | |
Q_ASSERT(m_positionSlot > -2); | |
} | |
Item ForClause::mapToItem(const Item &item, | |
const DynamicContext::Ptr &context) const | |
{ | |
context->setRangeVariable(m_varSlot, item); | |
return m_operand2->evaluateSingleton(context); | |
} | |
Item::Iterator::Ptr ForClause::mapToSequence(const Item &item, | |
const DynamicContext::Ptr &context) const | |
{ | |
context->setRangeVariable(m_varSlot, item); | |
return m_operand2->evaluateSequence(context); | |
} | |
void ForClause::riggPositionalVariable(const DynamicContext::Ptr &context, | |
const Item::Iterator::Ptr &source) const | |
{ | |
if(m_positionSlot > -1) | |
context->setPositionIterator(m_positionSlot, source); | |
} | |
Item::Iterator::Ptr ForClause::evaluateSequence(const DynamicContext::Ptr &context) const | |
{ | |
const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); | |
riggPositionalVariable(context, source); | |
if(m_allowsMany) | |
{ | |
return makeSequenceMappingIterator<Item>(ConstPtr(this), | |
source, | |
context); | |
} | |
else | |
{ | |
return makeItemMappingIterator<Item>(ConstPtr(this), | |
source, | |
context); | |
} | |
} | |
Item ForClause::evaluateSingleton(const DynamicContext::Ptr &context) const | |
{ | |
return evaluateSequence(context)->next(); | |
} | |
void ForClause::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const | |
{ | |
Item::Iterator::Ptr it; | |
const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); | |
riggPositionalVariable(context, source); | |
Item next(source->next()); | |
while(next) | |
{ | |
context->setRangeVariable(m_varSlot, next); | |
m_operand2->evaluateToSequenceReceiver(context); | |
next = source->next(); | |
} | |
} | |
Expression::Ptr ForClause::typeCheck(const StaticContext::Ptr &context, | |
const SequenceType::Ptr &reqType) | |
{ | |
const Expression::Ptr me(PairContainer::typeCheck(context, reqType)); | |
const Cardinality card(m_operand1->staticType()->cardinality()); | |
/* If our source is empty we will always evaluate to the empty sequence, so rewrite. */ | |
if(card.isEmpty()) | |
return EmptySequence::create(this, context); | |
else | |
return me; | |
/* This breaks because the variable references haven't rewritten themselves, so | |
* they dangle. When this is fixed, evaluateSingleton can be removed. */ | |
/* | |
else if(card->allowsMany()) | |
return me; | |
else | |
return m_operand2; | |
*/ | |
} | |
Expression::Ptr ForClause::compress(const StaticContext::Ptr &context) | |
{ | |
const Expression::Ptr me(PairContainer::compress(context)); | |
if(me != this) | |
return me; | |
/* This is done after calling PairContainer::typeCheck(). The advantage of this is that | |
* m_allowsMany is updated according to what the operand says after it has compressed. However, | |
* if it was initialized to false(as it once was..), ForClause::evaluateSequence() | |
* would potentially have been called by PairContainer::compress(), and it would have | |
* used an unsafe branch. */ | |
m_allowsMany = m_operand2->staticType()->cardinality().allowsMany(); | |
return me; | |
} | |
SequenceType::Ptr ForClause::staticType() const | |
{ | |
const SequenceType::Ptr returnType(m_operand2->staticType()); | |
return makeGenericSequenceType(returnType->itemType(), | |
m_operand1->staticType()->cardinality() | |
* /* multiply operator */ | |
returnType->cardinality()); | |
} | |
SequenceType::List ForClause::expectedOperandTypes() const | |
{ | |
SequenceType::List result; | |
result.append(CommonSequenceTypes::ZeroOrMoreItems); | |
result.append(CommonSequenceTypes::ZeroOrMoreItems); | |
return result; | |
} | |
ExpressionVisitorResult::Ptr ForClause::accept(const ExpressionVisitor::Ptr &visitor) const | |
{ | |
return visitor->visit(this); | |
} | |
OptimizationPass::List ForClause::optimizationPasses() const | |
{ | |
return OptimizationPasses::forPasses; | |
} | |
Expression::ID ForClause::id() const | |
{ | |
return IDForClause; | |
} | |
QT_END_NAMESPACE |