public static function parse(Parser $parser, TokensList $list, array $options = array())
{
$ret = new Expression();
/**
* Whether current tokens make an expression or a table reference.
*
* @var bool $isExpr
*/
$isExpr = false;
/**
* Whether a period was previously found.
*
* @var bool $dot
*/
$dot = false;
/**
* Whether an alias is expected. Is 2 if `AS` keyword was found.
*
* @var bool $alias
*/
$alias = false;
/**
* Counts brackets.
*
* @var int $brackets
*/
$brackets = 0;
/**
* Keeps track of the last two previous tokens.
*
* @var Token[] $prev
*/
$prev = array(null, null);
// When a field is parsed, no parentheses are expected.
if (!empty($options['parseField'])) {
$options['breakOnParentheses'] = true;
$options['field'] = $options['parseField'];
}
for (; $list->idx < $list->count; ++$list->idx) {
/**
* Token parsed at this moment.
*
* @var Token $token
*/
$token = $list->tokens[$list->idx];
// End of statement.
if ($token->type === Token::TYPE_DELIMITER) {
break;
}
// Skipping whitespaces and comments.
if ($token->type === Token::TYPE_WHITESPACE || $token->type === Token::TYPE_COMMENT) {
if ($isExpr) {
$ret->expr .= $token->token;
}
continue;
}
if ($token->type === Token::TYPE_KEYWORD) {
if ($brackets > 0 && empty($ret->subquery) && !empty(Parser::$STATEMENT_PARSERS[$token->value])) {
// A `(` was previously found and this keyword is the
// beginning of a statement, so this is a subquery.
$ret->subquery = $token->value;
} elseif ($token->flags & Token::FLAG_KEYWORD_FUNCTION && (empty($options['parseField']) && !$alias)) {
$isExpr = true;
} elseif ($token->flags & Token::FLAG_KEYWORD_RESERVED && $brackets === 0) {
if (empty(self::$ALLOWED_KEYWORDS[$token->value])) {
// A reserved keyword that is not allowed in the
// expression was found so the expression must have
// ended and a new clause is starting.
break;
}
if ($token->value === 'AS') {
if (!empty($options['breakOnAlias'])) {
break;
}
if ($alias) {
$parser->error(__('An alias was expected.'), $token);
break;
}
$alias = true;
continue;
} elseif ($token->value === 'CASE') {
// For a use of CASE like
// 'SELECT a = CASE .... END, b=1, `id`, ... FROM ...'
$tempCaseExpr = CaseExpression::parse($parser, $list);
$ret->expr .= CaseExpression::build($tempCaseExpr);
$isExpr = true;
continue;
}
$isExpr = true;
} elseif ($brackets === 0 && strlen($ret->expr) > 0 && !$alias) {
/* End of expression */
break;
}
}
if ($token->type === Token::TYPE_NUMBER || $token->type === Token::TYPE_BOOL || $token->type === Token::TYPE_SYMBOL && $token->flags & Token::FLAG_SYMBOL_VARIABLE || $token->type === Token::TYPE_OPERATOR && $token->value !== '.') {
if (!empty($options['parseField'])) {
break;
}
// Numbers, booleans and operators (except dot) are usually part
// of expressions.
$isExpr = true;
}
if ($token->type === Token::TYPE_OPERATOR) {
if (!empty($options['breakOnParentheses']) && ($token->value === '(' || $token->value === ')')) {
// No brackets were expected.
break;
}
if ($token->value === '(') {
++$brackets;
if (empty($ret->function) && $prev[1] !== null && ($prev[1]->type === Token::TYPE_NONE || $prev[1]->type === Token::TYPE_SYMBOL || $prev[1]->type === Token::TYPE_KEYWORD && $prev[1]->flags & Token::FLAG_KEYWORD_FUNCTION)) {
$ret->function = $prev[1]->value;
}
} elseif ($token->value === ')' && $brackets == 0) {
// Not our bracket
break;
} elseif ($token->value === ')') {
--$brackets;
if ($brackets === 0) {
if (!empty($options['parenthesesDelimited'])) {
// The current token is the last bracket, the next
// one will be outside the expression.
$ret->expr .= $token->token;
++$list->idx;
break;
}
} elseif ($brackets < 0) {
// $parser->error(__('Unexpected closing bracket.'), $token);
// $brackets = 0;
break;
}
} elseif ($token->value === ',') {
// Expressions are comma-delimited.
if ($brackets === 0) {
break;
}
}
}
// Saving the previous tokens.
$prev[0] = $prev[1];
$prev[1] = $token;
if ($alias) {
// An alias is expected (the keyword `AS` was previously found).
if (!empty($ret->alias)) {
$parser->error(__('An alias was previously found.'), $token);
break;
}
$ret->alias = $token->value;
$alias = false;
} elseif ($isExpr) {
// Handling aliases.
if ($brackets === 0 && ($prev[0] === null || ($prev[0]->type !== Token::TYPE_OPERATOR || $prev[0]->token === ')') && ($prev[0]->type !== Token::TYPE_KEYWORD || !($prev[0]->flags & Token::FLAG_KEYWORD_RESERVED))) && ($prev[1]->type === Token::TYPE_STRING || $prev[1]->type === Token::TYPE_SYMBOL && !($prev[1]->flags & Token::FLAG_SYMBOL_VARIABLE) || $prev[1]->type === Token::TYPE_NONE)) {
if (!empty($ret->alias)) {
$parser->error(__('An alias was previously found.'), $token);
break;
}
$ret->alias = $prev[1]->value;
} else {
$ret->expr .= $token->token;
}
} elseif (!$isExpr) {
if ($token->type === Token::TYPE_OPERATOR && $token->value === '.') {
// Found a `.` which means we expect a column name and
// the column name we parsed is actually the table name
// and the table name is actually a database name.
if (!empty($ret->database) || $dot) {
$parser->error(__('Unexpected dot.'), $token);
}
$ret->database = $ret->table;
$ret->table = $ret->column;
$ret->column = null;
$dot = true;
$ret->expr .= $token->token;
} else {
$field = empty($options['field']) ? 'column' : $options['field'];
if (empty($ret->{$field})) {
$ret->{$field} = $token->value;
$ret->expr .= $token->token;
$dot = false;
} else {
// No alias is expected.
if (!empty($options['breakOnAlias'])) {
break;
}
if (!empty($ret->alias)) {
$parser->error(__('An alias was previously found.'), $token);
break;
}
$ret->alias = $token->value;
}
}
}
}
if ($alias) {
$parser->error(__('An alias was expected.'), $list->tokens[$list->idx - 1]);
}
// White-spaces might be added at the end.
$ret->expr = trim($ret->expr);
if ($ret->expr === '') {
return null;
}
--$list->idx;
return $ret;
}
