/**
* SimpleConditionalExpression ::=
* ComparisonExpression | BetweenExpression | LikeExpression |
* InExpression | NullComparisonExpression | ExistsExpression |
* EmptyCollectionComparisonExpression | CollectionMemberExpression
*/
public function SimpleConditionalExpression()
{
if ($this->_lexer->isNextToken(Lexer::T_NOT)) {
$token = $this->_lexer->glimpse();
} else {
$token = $this->_lexer->lookahead;
}
if ($token['type'] === Lexer::T_EXISTS) {
return $this->ExistsExpression();
}
$pathExprOrInputParam = false;
if ($token['type'] === Lexer::T_IDENTIFIER || $token['type'] === Lexer::T_INPUT_PARAMETER) {
// Peek beyond the PathExpression
$pathExprOrInputParam = true;
$peek = $this->_lexer->peek();
while ($peek['value'] === '.') {
$this->_lexer->peek();
$peek = $this->_lexer->peek();
}
// Also peek beyond a NOT if there is one
if ($peek['type'] === Lexer::T_NOT) {
$peek = $this->_lexer->peek();
}
$token = $peek;
// We need to go even further in case of IS (differenciate between NULL and EMPTY)
$lookahead = $this->_lexer->peek();
// Also peek beyond a NOT if there is one
if ($lookahead['type'] === Lexer::T_NOT) {
$lookahead = $this->_lexer->peek();
}
$this->_lexer->resetPeek();
}
if ($pathExprOrInputParam) {
switch ($token['type']) {
case Lexer::T_EQUALS:
case Lexer::T_LOWER_THAN:
case Lexer::T_GREATER_THAN:
case Lexer::T_NEGATE:
case Lexer::T_OPEN_PARENTHESIS:
return $this->ComparisonExpression();
case Lexer::T_BETWEEN:
return $this->BetweenExpression();
case Lexer::T_LIKE:
return $this->LikeExpression();
case Lexer::T_IN:
return $this->InExpression();
case Lexer::T_IS:
if ($lookahead['type'] == Lexer::T_NULL) {
return $this->NullComparisonExpression();
}
return $this->EmptyCollectionComparisonExpression();
case Lexer::T_MEMBER:
return $this->CollectionMemberExpression();
default:
$this->syntaxError();
}
}
return $this->ComparisonExpression();
}
/**
* SimpleConditionalExpression ::=
* ComparisonExpression | BetweenExpression | LikeExpression |
* InExpression | NullComparisonExpression | ExistsExpression |
* EmptyCollectionComparisonExpression | CollectionMemberExpression |
* InstanceOfExpression
*/
public function SimpleConditionalExpression()
{
if ($this->_lexer->isNextToken(Lexer::T_NOT)) {
$token = $this->_lexer->glimpse();
} else {
$token = $this->_lexer->lookahead;
}
if ($token['type'] === Lexer::T_EXISTS) {
return $this->ExistsExpression();
}
$peek = $this->_lexer->glimpse();
if ($token['type'] === Lexer::T_IDENTIFIER || $token['type'] === Lexer::T_INPUT_PARAMETER) {
if ($peek['value'] == '(') {
// Peek beyond the matching closing paranthesis ')'
$this->_lexer->peek();
$token = $this->_peekBeyondClosingParenthesis();
} else {
// Peek beyond the PathExpression (or InputParameter)
$peek = $this->_lexer->peek();
while ($peek['value'] === '.') {
$this->_lexer->peek();
$peek = $this->_lexer->peek();
}
// Also peek beyond a NOT if there is one
if ($peek['type'] === Lexer::T_NOT) {
$peek = $this->_lexer->peek();
}
$token = $peek;
// We need to go even further in case of IS (differenciate between NULL and EMPTY)
$lookahead = $this->_lexer->peek();
// Also peek beyond a NOT if there is one
if ($lookahead['type'] === Lexer::T_NOT) {
$lookahead = $this->_lexer->peek();
}
$this->_lexer->resetPeek();
}
}
switch ($token['type']) {
case Lexer::T_BETWEEN:
return $this->BetweenExpression();
case Lexer::T_LIKE:
return $this->LikeExpression();
case Lexer::T_IN:
return $this->InExpression();
case Lexer::T_INSTANCE:
return $this->InstanceOfExpression();
case Lexer::T_IS:
if ($lookahead['type'] == Lexer::T_NULL) {
return $this->NullComparisonExpression();
}
return $this->EmptyCollectionComparisonExpression();
case Lexer::T_MEMBER:
return $this->CollectionMemberExpression();
default:
return $this->ComparisonExpression();
}
}
/**
* Peeks beyond the specified token and returns the first token after that one.
*/
private function _peekBeyond($token)
{
$peek = $this->_lexer->peek();
while ($peek['value'] != $token) {
$peek = $this->_lexer->peek();
}
$peek = $this->_lexer->peek();
$this->_lexer->resetPeek();
return $peek;
}
private function _peekBeyondClosingParenthesis()
{
$numUnmatched = 1;
$token = $this->_lexer->peek();
while ($numUnmatched > 0 && $token !== null) {
if ($token['value'] == ')') {
--$numUnmatched;
} else {
if ($token['value'] == '(') {
++$numUnmatched;
}
}
$token = $this->_lexer->peek();
}
$this->_lexer->resetPeek();
return $token;
}
