/**
* Emulates a loose comparison between two types, and returns the result.
*
* The result can be true, false, or unknown:
*
* - true: loose comparison of these types is always true
* - false: loose comparison of these types is always false
* - unknown: outcome depends on the actual values of these types
*
* @see http://php.net/manual/en/types.comparisons.php (table with loose comparison ==)
*
* @param PhpType $thisType
* @param PhpType $thatType
*/
public function testForEquality(PhpType $that)
{
if ($that->isAllType() || $that->isUnknownType() || $that->isNoResolvedType() || $this->isAllType() || $this->isUnknownType() || $this->isNoResolvedType()) {
return TernaryValue::get('unknown');
}
if ($this->isNoType() || $that->isNoType()) {
if ($this->isNoType() && $that->isNoType()) {
return TernaryValue::get('true');
}
return TernaryValue::get('unknown');
}
$isThisNumeric = $this->isIntegerType() || $this->isDoubleType();
$isThatNumeric = $that->isIntegerType() || $that->isDoubleType();
if (($isThisNumeric || $this->isStringType()) && $that->isArrayType() || ($isThatNumeric || $that->isStringType()) && $this->isArrayType()) {
return TernaryValue::get('false');
}
if ($this->isObjectType() ^ $that->isObjectType()) {
return TernaryValue::get('false');
}
if ($that->isUnionType()) {
return $that->testForEquality($this);
}
if ($this->isArrayType() && $that->isArrayType()) {
// TODO: Maybe make this more sophisticated by looking at the key,
// and element types.
return TernaryValue::get('unknown');
}
// If this is reached, then this base type does not have enough information to
// make an informed decision, but the method should be overridden by a subtype
// as this method eventually is never allowed to return null.
return null;
}