Make filters comparable

src/Filter/Chain.php

@@ -42,6 +42,35 @@ public function __clone()
         }
     }
 
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if (count($rule) !== count($this->rules)) {
+            return false;
+        }
+
+        $theirRules = iterator_to_array($rule);
+        foreach ($this->rules as $myRule) {
+            $found = false;
+            foreach ($theirRules as $i => $theirRule) {
+                if ($myRule->sameAs($theirRule)) {
+                    unset($theirRules[$i]);
+                    $found = true;
+                    break;
+                }
+            }
+
+            if (! $found) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     /**
      * Get an iterator this chain's rules
      *

src/Filter/Condition.php

@@ -34,6 +34,13 @@ public function __clone()
         }
     }
 
+    public function sameAs(Rule $rule): bool
+    {
+        return $rule instanceof static
+            && $rule->getColumn() === $this->getColumn()
+            && $rule->getValue() === $this->getValue();
+    }
+
     /**
      * Set this condition's column
      *

src/Filter/Equal.php

@@ -28,4 +28,21 @@
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($this->ignoresCase() !== $rule->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }

src/Filter/Like.php

@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($rule->ignoresCase() !== $this->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }

src/Filter/Rule.php

@@ -4,4 +4,12 @@
 
 interface Rule
 {
+    /**
+     * Get whether the given rule is semantically the same as this one
+     *
+     * @param Rule $rule
+     *
+     * @return bool
+     */
+    public function sameAs(Rule $rule): bool;
 }

src/Filter/Unequal.php

@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($this->ignoresCase() !== $rule->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }

src/Filter/Unlike.php

@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($rule->ignoresCase() !== $this->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }