public function testExpressionWalkerWorks()
{
$expression = O\Expression::variable(O\Expression::value('foo'));
$expressionWalker = new O\DynamicExpressionWalker([O\ValueExpression::getType() => function (O\ValueExpression $expression) {
return O\Expression::value('bar');
}]);
$newExpression = $expressionWalker->walk($expression);
$this->assertNotEquals($expression, $newExpression);
$this->assertSame($newExpression->getName()->getValue(), 'bar');
}
public function getSource()
{
if ($this->isSource()) {
return $this;
} else {
$expression = $this->expression;
while ($expression instanceof O\TraversalExpression) {
$expression = $expression->getValue();
}
if ($expression instanceof O\ValueExpression) {
return $expression->getValue();
} else {
throw new PinqException('Invalid origin expression: must be instance of %s', O\ValueExpression::getType());
}
}
}
public function interpretSource(O\Expression $expression)
{
$isQueryScope = false;
$queryableQueryResolver = new O\DynamicExpressionWalker([O\TraversalExpression::getType() => function (O\TraversalExpression $expression, O\ExpressionWalker $self) use(&$isQueryScope) {
$expression = $expression->updateValue($self->walk($expression->getValue()));
if ($isQueryScope) {
return $expression;
} else {
return $self->walk(O\Expression::value($expression->evaluate($this->evaluationContext)));
}
}, O\ValueExpression::getType() => function (O\ValueExpression $expression) use(&$isQueryScope) {
if ($expression->getValue() instanceof IQueryable) {
$isQueryScope = true;
}
return $expression;
}]);
$expression = $queryableQueryResolver->walk($expression);
if ($isQueryScope) {
$this->scopeInterpreter->interpretScope($expression);
$this->interpretation->interpretQueryScope($this->getId('source-scope'), $this->scopeInterpreter->getInterpretation());
} else {
$this->interpretation->interpretArrayOrIterator($this->getId('source-iterator'), $expression->evaluate($this->evaluationContext));
}
}
public function tryComputeResults(O\Expression $queryExpression, &$results)
{
if (isset($this->storage[$queryExpression])) {
$results = $this->storage[$queryExpression];
return true;
}
$foundApplicableResults = false;
//Searches the query expression tree and checks if any parent expressions have saved results
//If so, the expression tree is updated with a Traversable implementation with the saved results
$applicableScopeFinder = function (O\Expression $expression, O\ExpressionWalker $self) use(&$foundApplicableResults) {
if (isset($this->storage[$expression])) {
$foundApplicableResults = true;
return O\Expression::value($this->newTraversable($this->storage[$expression]));
}
if ($expression instanceof O\ValueExpression) {
return $expression;
}
/** @var $expression O\TraversalExpression */
return $expression->updateValue($self->walk($expression->getValue()));
};
$traversalWalker = new O\DynamicExpressionWalker([O\TraversalExpression::getType() => $applicableScopeFinder, O\ValueExpression::getType() => $applicableScopeFinder]);
$remainingQueryExpression = $traversalWalker->walk($queryExpression);
//If found applicable results, execute the updated expression tree against the Traversable
//implementation to compute the result of the query.
$results = $foundApplicableResults ? $remainingQueryExpression->evaluate() : null;
return $foundApplicableResults;
}
/**
* Compiles the expression tree into debug code.
*
* @return string
*/
public final function compileDebug()
{
return (new DynamicExpressionWalker([ValueExpression::getType() => function (ValueExpression $expression) {
$value = $expression->getValue();
return !is_scalar($value) && $value !== null ? Expression::constant('{' . Utilities::getTypeOrClass($expression->getValue()) . '}') : $expression;
}]))->walk($this)->compile();
}