Optimize isSymbol

Signed-off-by: Kamil Tekiela <[email protected]>

Author: kamil-tekiela

psalm-baseline.xml

@@ -229,7 +229,6 @@
       <code><![CDATA[$keywordToken->value]]></code>
     </PropertyTypeCoercion>
     <RiskyTruthyFalsyComparison>
-      <code><![CDATA[! $flags]]></code>
       <code><![CDATA[! $flags]]></code>
       <code><![CDATA[! $flags]]></code>
       <code><![CDATA[Context::isComment($token)]]></code>

src/Context.php

@@ -445,25 +445,14 @@ public static function isNumber(string $string): bool
      *
      * @return int|null the appropriate flag for the symbol type
      */
-    public static function isSymbol(string $string): int|null
+    public static function isSymbol(string $character): int|null
     {
-        if ($string === '') {
-            return null;
-        }
-
-        if (str_starts_with($string, '@')) {
-            return Token::FLAG_SYMBOL_VARIABLE;
-        }
-
-        if (str_starts_with($string, '`')) {
-            return Token::FLAG_SYMBOL_BACKTICK;
-        }
-
-        if (str_starts_with($string, ':') || str_starts_with($string, '?')) {
-            return Token::FLAG_SYMBOL_PARAMETER;
-        }
-
-        return null;
+        return match ($character) {
+            '@' => Token::FLAG_SYMBOL_VARIABLE,
+            '`' => Token::FLAG_SYMBOL_BACKTICK,
+            ':', '?' => Token::FLAG_SYMBOL_PARAMETER,
+            default => null,
+        };
     }
 
     /**

src/Lexer.php

@@ -918,7 +918,7 @@ public function parseSymbol(): Token|null
         $token = $this->str[$this->last];
         $flags = Context::isSymbol($token);
 
-        if (! $flags) {
+        if ($flags === null) {
             return null;
         }
 

tests/Lexer/IsMethodsTest.php

@@ -115,12 +115,11 @@ public function testIsSymbol(): void
     {
         $this->assertEquals(Token::FLAG_SYMBOL_VARIABLE, Context::isSymbol('@'));
         $this->assertEquals(Token::FLAG_SYMBOL_BACKTICK, Context::isSymbol('`'));
-
-        $this->assertEquals(Token::FLAG_SYMBOL_VARIABLE, Context::isSymbol('@id'));
-        $this->assertEquals(Token::FLAG_SYMBOL_BACKTICK, Context::isSymbol('`id`'));
+        $this->assertEquals(Token::FLAG_SYMBOL_PARAMETER, Context::isSymbol(':'));
+        $this->assertEquals(Token::FLAG_SYMBOL_PARAMETER, Context::isSymbol('?'));
 
         $this->assertNull(Context::isSymbol(''));
-        $this->assertNull(Context::isSymbol('id'));
+        $this->assertNull(Context::isSymbol('i'));
     }
 
     public function testisSeparator(): void