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Add parsing of CASE Expressions
Fix phpmyadmin/phpmyadmin#12100 Signed-off-by: Deven Bansod <devenbansod.bits@gmail.com>
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‎src/Components/CaseExpression.php‎

Lines changed: 284 additions & 0 deletions
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<?php
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/**
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* Parses a reference to a CASE expression
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*
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* @package SqlParser
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* @subpackage Components
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*/
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namespace SqlParser\Components;
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use SqlParser\Context;
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use SqlParser\Component;
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use SqlParser\Parser;
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use SqlParser\Token;
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use SqlParser\TokensList;
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/**
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* Parses a reference to a CASE expression
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*
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* @category Components
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* @package SqlParser
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* @subpackage Components
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* @author Deven Bansod <devenbansod.bits@gmail.com>
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* @license http://opensource.org/licenses/GPL-2.0 GNU Public License
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*/
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class CaseExpression extends Component
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{
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/**
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* The value to be compared
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*
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* @var Expression
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*/
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public $value;
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/**
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* The conditions in WHEN clauses
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*
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* @var array
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*/
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public $conditions;
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/**
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* The results matching with the WHEN clauses
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*
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* @var array
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*/
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public $results;
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/**
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* The values to be compared against
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*
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* @var array
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*/
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public $compare_values;
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/**
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* The result in ELSE section of expr
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*
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* @var array
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*/
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public $else_result;
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/**
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* Constructor.
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*
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*/
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public function __construct()
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{
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}
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/**
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*
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* @param Parser $parser The parser that serves as context.
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* @param TokensList $list The list of tokens that are being parsed.
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*
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* @return Expression
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*/
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public static function parse(Parser $parser, TokensList $list)
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{
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$ret = new CaseExpression();
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/**
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* Counts brackets.
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*
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* @var int $brackets
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*/
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$brackets = 0;
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/**
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* Keeps track of the last two previous tokens.
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*
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* @var Token[] $prev
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*/
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$prev = array(null, null);
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/**
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* State of parser
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*
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* @var int $parser
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*/
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$state = 0;
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/**
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* Syntax type (type 0 or type 1)
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*
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* @var int $type
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*/
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$type = 0;
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++$list->idx; // Skip 'CASE'
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for (; $list->idx < $list->count; ++$list->idx) {
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/**
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* Token parsed at this moment.
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*
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* @var Token $token
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*/
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$token = $list->tokens[$list->idx];
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// End of statement.
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if ($token->type === Token::TYPE_DELIMITER) {
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break;
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}
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// Skipping whitespaces and comments.
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if (($token->type === Token::TYPE_WHITESPACE)
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|| ($token->type === Token::TYPE_COMMENT)
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) {
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continue;
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}
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if ($state === 0) {
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if ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'WHEN'
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) {
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++$list->idx; // Skip 'WHEN'
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$new_condition = Condition::parse($parser, $list);
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$type = 1;
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$state = 1;
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$ret->conditions[] = $new_condition;
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} elseif ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'ELSE'
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) {
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++$list->idx; // Skip 'ELSE'
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$ret->else_result = Expression::parse($parser, $list);
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$state = 0; // last clause of CASE expression
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} elseif ($token->type === Token::TYPE_KEYWORD
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&& ($token->value === 'END'
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|| $token->value === 'end')
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) {
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$state = 3; // end of CASE expression
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++$list->idx;
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break;
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} elseif ($token->type === Token::TYPE_KEYWORD) {
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$parser->error(__('Unexpected keyword'), $token);
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break;
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} else {
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$ret->value = Expression::parse($parser, $list);
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$type = 0;
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$state = 1;
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}
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} elseif ($state === 1) {
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if ($type === 0) {
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if ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'WHEN'
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) {
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++$list->idx; // Skip 'WHEN'
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$new_value = Expression::parse($parser, $list);
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$state = 2;
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$ret->compare_values[] = $new_value;
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} elseif ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'ELSE'
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) {
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++$list->idx; // Skip 'ELSE'
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$ret->else_result = Expression::parse($parser, $list);
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$state = 0; // last clause of CASE expression
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} elseif ($token->type === Token::TYPE_KEYWORD
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&& ($token->value === 'END'
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|| $token->value === 'end')
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) {
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$state = 3; // end of CASE expression
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++$list->idx;
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break;
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} elseif ($token->type === Token::TYPE_KEYWORD) {
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$parser->error(__('Unexpected keyword'), $token);
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break;
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} else {
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$parser->error(__('Unexpected token'), $token);
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break;
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}
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} else {
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if ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'THEN'
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) {
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++$list->idx; // Skip 'THEN'
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$new_result = Expression::parse($parser, $list);
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$state = 0;
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$ret->results[] = $new_result;
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} elseif ($token->type === Token::TYPE_KEYWORD) {
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$parser->error(__('Unexpected keyword'), $token);
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break;
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} else {
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$parser->error(__('Unexpected token'), $token);
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break;
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}
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}
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} elseif ($state === 2) {
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if ($type === 0) {
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if ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'THEN'
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) {
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++$list->idx; // Skip 'THEN'
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$new_result = Expression::parse($parser, $list);
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$ret->results[] = $new_result;
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$state = 1;
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} elseif ($token->type === Token::TYPE_KEYWORD) {
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$parser->error(__('Unexpected keyword'), $token);
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break;
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} else {
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$parser->error(__('Unexpected token'), $token);
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break;
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}
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} else {
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$parser->error(__('Unexpected token'), $token);
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break;
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}
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}
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}
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if ($state !== 3) {
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$parser->error(
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__('Unexpected end of CASE expression'),
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$list->list[$list->idx - 1]
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);
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}
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--$list->idx;
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return $ret;
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}
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/**
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* @param Expression $component The component to be built.
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* @param array $options Parameters for building.
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*
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* @return string
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*/
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public static function build($component, array $options = array())
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{
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$ret = 'CASE ';
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if (isset($component->value)) {
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// Syntax type 0
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$ret .= $component->value . ' ';
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for (
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$i = 0;
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$i < count($component->compare_values) && $i < count($component->results);
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$i++
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) {
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$ret .= 'WHEN ' . $component->compare_values[$i] . ' ';
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$ret .= 'THEN ' . $component->results[$i] . ' ';
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}
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} else {
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// Syntax type 1
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for (
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$i = 0;
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$i < count($component->conditions) && $i < count($component->results);
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$i++
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) {
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$ret .= 'WHEN ' . Condition::build($component->conditions[$i]) . ' ';
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$ret .= 'THEN ' . $component->results[$i] . ' ';
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}
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}
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if (isset($component->else_result)) {
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$ret .= 'ELSE ' . $component->else_result . ' ';
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}
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$ret .= 'END';
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return $ret;
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}
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}

‎src/Components/ExpressionArray.php‎

Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
<?php
22

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/**
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* Parses a a list of expressions delimited by a comma.
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* Parses a list of expressions delimited by a comma.
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*
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* @package SqlParser
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* @subpackage Components
@@ -14,7 +14,7 @@
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use SqlParser\TokensList;
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/**
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* Parses a a list of expressions delimited by a comma.
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* Parses a list of expressions delimited by a comma.
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*
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* @category Keywords
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* @package SqlParser
@@ -73,13 +73,21 @@ public static function parse(Parser $parser, TokensList $list, array $options =
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&& ((~$token->flags & Token::FLAG_KEYWORD_FUNCTION))
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&& ($token->value !== 'DUAL')
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&& ($token->value !== 'NULL')
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&& ($token->value !== 'CASE')
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) {
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// No keyword is expected.
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break;
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}
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if ($state === 0) {
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$expr = Expression::parse($parser, $list, $options);
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if ($token->type === Token::TYPE_KEYWORD
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&& $token->value === 'CASE'
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) {
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$expr = CaseExpression::parse($parser, $list, $options);
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} else {
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$expr = Expression::parse($parser, $list, $options);
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}
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if ($expr === null) {
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break;
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}

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