FEAT: add first draft of autogenerated class diagram

This is a first hack to implement a new feature to generate
class diagrams based on user defined queries.

And example of such page is:

```
Element Structure
=================

.. phpdoc:class-diagram:: [?(@.namespace starts_with "\phpDocumentor\Descriptor")]
```

More features need to be implemented, but this starts as a POC to
see what we actually need to complete this feature.

Author: jaapio

src/AST/Comparison.php

@@ -30,6 +30,8 @@ public function visit(Executor $param, $currentObject, $root): bool
     {
         return match ($this->operator) {
             '==' => $param->evaluateEqualsComparison($root, $currentObject, $this->left, $this->right),
+            '!=' => $param->evaluateNotEqualsComparison($root, $currentObject, $this->left, $this->right),
+            'starts_with' => $param->evaluateStartsWithComparison($root, $currentObject, $this->left, $this->right),
             default => throw new InvalidArgumentException(),
         };
     }

src/Executor.php

@@ -31,6 +31,7 @@
 use function is_object;
 use function is_string;
 use function iterator_to_array;
+use function str_starts_with;
 use function strrpos;
 use function substr;
 
@@ -49,8 +50,12 @@ public function evaluate(QueryNode $query, mixed $currentElement, mixed $rootEle
         return $query->visit($this, $currentElement, $rootElement);
     }
 
-    public function evaluateEqualsComparison(mixed $root, mixed $currentObject, QueryNode $left, QueryNode $right): bool
-    {
+    public function evaluateEqualsComparison(
+        mixed $root,
+        mixed $currentObject,
+        QueryNode $left,
+        QueryNode $right,
+    ): bool {
         $leftValue = $this->toValue($this->evaluate($left, $currentObject, $root));
         $rightValue = $this->toValue($this->evaluate($right, $currentObject, $root));
 
@@ -61,6 +66,27 @@ public function evaluateEqualsComparison(mixed $root, mixed $currentObject, Quer
         return $leftValue === $rightValue;
     }
 
+    public function evaluateNotEqualsComparison(
+        mixed $root,
+        mixed $currentObject,
+        QueryNode $left,
+        QueryNode $right,
+    ): bool {
+        return ! $this->evaluateEqualsComparison($root, $currentObject, $left, $right);
+    }
+
+    public function evaluateStartsWithComparison(
+        mixed $root,
+        mixed $currentObject,
+        QueryNode $left,
+        QueryNode $right,
+    ): bool {
+        $leftValue = $this->toValue($this->evaluate($left, $currentObject, $root));
+        $rightValue = $this->toValue($this->evaluate($right, $currentObject, $root));
+
+        return str_starts_with((string) $leftValue, (string) $rightValue);
+    }
+
     /**
      * @param Generator<mixed>|mixed $value
      *

src/Parser/ParserBuilder.php

@@ -96,6 +96,8 @@ private static function expression(): Parser
     {
         $operator = choice(
             string('=='),
+            string('!='),
+            string('starts_with'),
         );
 
         $value = choice(

tests/unit/Parser/ParserBuilderTest.php

@@ -13,6 +13,7 @@
 
 namespace phpDocumentor\JsonPath\Parser;
 
+use Generator;
 use Parsica\Parsica\Parser;
 use phpDocumentor\JsonPath\AST\Comparison;
 use phpDocumentor\JsonPath\AST\CurrentNode;
@@ -101,9 +102,10 @@ public function testRootFieldChildAccess(): void
         );
     }
 
-    public function testFilterExpressionCurrentObjectPropertyEquals(): void
+    /** @dataProvider operatorProvider */
+    public function testFilterExpression(string $operator): void
     {
-        $result = $this->parser->tryString('$.store.books[?(@.title == "phpDoc")]');
+        $result = $this->parser->tryString('$.store.books[?(@.title ' . $operator . ' "phpDoc")]');
         self::assertEquals(
             new Path([
                 new RootNode(),
@@ -119,7 +121,7 @@ public function testFilterExpressionCurrentObjectPropertyEquals(): void
                             new CurrentNode(),
                             new FieldAccess(new FieldName('title')),
                         ]),
-                        '==',
+                        $operator,
                         new Value(
                             'phpDoc',
                         ),
@@ -130,6 +132,20 @@ public function testFilterExpressionCurrentObjectPropertyEquals(): void
         );
     }
 
+    /** @return Generator<string, string> */
+    public static function operatorProvider(): Generator
+    {
+        $operators = [
+            '==',
+            '!=',
+            'starts_with',
+        ];
+
+        foreach ($operators as $operator) {
+            yield $operator => [$operator];
+        }
+    }
+
     public function testFilterExpressionCurrentObjectProperyWildCard(): void
     {
         $result = $this->parser->tryString('$.store.books[?(@.* == "phpDoc")]');