Condition: Allow IF in conditions.

Author: udan11

src/Components/Condition.php

@@ -30,17 +30,18 @@ class Condition extends Component
      *
      * @var array
      */
-    public static $DELIMITERS = array('&&', 'AND', 'OR', 'XOR', '||');
+    public static $DELIMITERS = array('&&', '||', 'AND', 'OR', 'XOR');
 
     /**
-     * Hash map containing reserved keywords that are also operators.
+     * List of allowed reserved keywords in conditions.
      *
      * @var array
      */
-    public static $OPERATORS = array(
+    public static $ALLOWED_KEYWORDS = array(
         'AND'                           => 1,
         'BETWEEN'                       => 1,
         'EXISTS'                        => 1,
+        'IF'                            => 1,
         'IN'                            => 1,
         'IS'                            => 1,
         'LIKE'                          => 1,
@@ -106,6 +107,7 @@ public static function parse(Parser $parser, TokensList $list, array $options =
 
         /**
          * Whether there was a `BETWEEN` keyword before or not.
+         *
          * It is required to keep track of them because their structure contains
          * the keyword `AND`, which is also an operator that delimits
          * expressions.
@@ -115,6 +117,7 @@ public static function parse(Parser $parser, TokensList $list, array $options =
         $betweenBefore = false;
 
         for (; $list->idx < $list->count; ++$list->idx) {
+
             /**
              * Token parsed at this moment.
              *
@@ -142,11 +145,12 @@ public static function parse(Parser $parser, TokensList $list, array $options =
             // Conditions are delimited by logical operators.
             if (in_array($token->value, static::$DELIMITERS, true)) {
                 if (($betweenBefore) && ($token->value === 'AND')) {
+                    // The syntax of keyword `BETWEEN` is hard-coded.
                     $betweenBefore = false;
                 } else {
+                    // The expression ended.
                     $expr->expr = trim($expr->expr);
                     if (!empty($expr->expr)) {
-                        // Adding the condition that is delimited by this operator.
                         $ret[] = $expr;
                     }
 
@@ -155,36 +159,39 @@ public static function parse(Parser $parser, TokensList $list, array $options =
                     $expr->isOperator = true;
                     $ret[] = $expr;
 
+                    // Preparing to parse another condition.
                     $expr = new Condition();
                     continue;
                 }
             }
 
-            if ($token->type === Token::TYPE_OPERATOR) {
-                if ($token->value === '(') {
-                    ++$brackets;
-                } elseif ($token->value === ')') {
-                    --$brackets;
-                }
-            }
-
-            // No keyword is expected.
             if (($token->type === Token::TYPE_KEYWORD) && ($token->flags & Token::FLAG_KEYWORD_RESERVED)) {
                 if ($token->value === 'BETWEEN') {
                     $betweenBefore = true;
                 }
-                if (($brackets === 0) && (empty(static::$OPERATORS[$token->value]))) {
+                if (($brackets === 0) && (empty(static::$ALLOWED_KEYWORDS[$token->value]))) {
                     break;
                 }
             }
 
+            if ($token->type === Token::TYPE_OPERATOR) {
+                if ($token->value === '(') {
+                    ++$brackets;
+                } elseif ($token->value === ')') {
+                    --$brackets;
+                }
+            }
+
             $expr->expr .= $token->token;
             if (($token->type === Token::TYPE_NONE)
-                || (($token->type === Token::TYPE_KEYWORD) && (!($token->flags & Token::FLAG_KEYWORD_RESERVED)))
+                || (($token->type === Token::TYPE_KEYWORD)
+                    && (!($token->flags & Token::FLAG_KEYWORD_RESERVED)))
                 || ($token->type === Token::TYPE_STRING)
                 || ($token->type === Token::TYPE_SYMBOL)
             ) {
-                $expr->identifiers[] = $token->value;
+                if (!in_array($token->value, $expr->identifiers)) {
+                    $expr->identifiers[] = $token->value;
+                }
             }
         }