diff --git a/.idea/php-test-framework.xml b/.idea/php-test-framework.xml
new file mode 100644
index 0000000..d766127
--- /dev/null
+++ b/.idea/php-test-framework.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="PhpTestFrameworkVersionCache">
+    <tools_cache>
+      <tool tool_name="PHPUnit">
+        <cache>
+          <versions>
+            <info id="Local/home/jclain/wop/php/nur-sery/vendor/autoload.php" version="9.6.20" />
+          </versions>
+        </cache>
+      </tool>
+    </tools_cache>
+  </component>
+</project>
\ No newline at end of file
diff --git a/tests/wip/php/access/KeyAccessTest.php b/tests/wip/php/access/KeyAccessTest.php
new file mode 100644
index 0000000..2b1c8ff
--- /dev/null
+++ b/tests/wip/php/access/KeyAccessTest.php
@@ -0,0 +1,66 @@
+<?php
+namespace nur\sery\wip\php\access;
+
+use nulib\tests\TestCase;
+use stdClass;
+
+class KeyAccessTest extends TestCase {
+  function testAccess() {
+    $default = new stdClass();
+    $array = ["null" => null, "false" => false, "empty" => ""];
+
+    #
+    $a = new KeyAccess($array, "inexistant");
+    self::assertFalse($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $a = new KeyAccess($array, "null");
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame(null, $a->get($default));
+
+    $a = new KeyAccess($array, "false");
+    self::assertTrue($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $a = new KeyAccess($array, "empty");
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame("", $a->get($default));
+
+    #
+    $a = new KeyAccess($array, "null", ["allow_null" => false]);
+    self::assertTrue($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $a = new KeyAccess($array, "null", ["allow_null" => true]);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame(null, $a->get($default));
+
+    #
+    $a = new KeyAccess($array, "false", ["allow_false" => false]);
+    self::assertTrue($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $a = new KeyAccess($array, "false", ["allow_false" => true]);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame(false, $a->get($default));
+
+    #
+    $a = new KeyAccess($array, "empty", ["allow_empty" => false]);
+    self::assertTrue($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $a = new KeyAccess($array, "empty", ["allow_empty" => true]);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame("", $a->get($default));
+  }
+}
diff --git a/tests/wip/php/access/ValueAccessTest.php b/tests/wip/php/access/ValueAccessTest.php
new file mode 100644
index 0000000..3bd9333
--- /dev/null
+++ b/tests/wip/php/access/ValueAccessTest.php
@@ -0,0 +1,69 @@
+<?php
+namespace nur\sery\wip\php\access;
+
+use nulib\tests\TestCase;
+use stdClass;
+
+class ValueAccessTest extends TestCase {
+  function testAccess() {
+    $default = new stdClass();
+
+    #
+    $i = null;
+    $a = new ValueAccess($i);
+    self::assertFalse($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $i = false;
+    $a = new ValueAccess($i);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame(false, $a->get($default));
+
+    $i = "";
+    $a = new ValueAccess($i);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame("", $a->get($default));
+
+    #
+    $i = null;
+    $a = new ValueAccess($i, ["allow_null" => false]);
+    self::assertFalse($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $i = null;
+    $a = new ValueAccess($i, ["allow_null" => true]);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame(null, $a->get($default));
+
+    #
+    $i = false;
+    $a = new ValueAccess($i, ["allow_false" => false]);
+    self::assertTrue($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $i = false;
+    $a = new ValueAccess($i, ["allow_false" => true]);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame(false, $a->get($default));
+
+    #
+    $i = "";
+    $a = new ValueAccess($i, ["allow_empty" => false]);
+    self::assertTrue($a->exists());
+    self::assertFalse($a->available());
+    self::assertSame($default, $a->get($default));
+
+    $i = "";
+    $a = new ValueAccess($i, ["allow_empty" => true]);
+    self::assertTrue($a->exists());
+    self::assertTrue($a->available());
+    self::assertSame("", $a->get($default));
+  }
+}
diff --git a/wip/php/access/KeyAccess.php b/wip/php/access/KeyAccess.php
index cd6dcf8..8010a12 100644
--- a/wip/php/access/KeyAccess.php
+++ b/wip/php/access/KeyAccess.php
@@ -36,15 +36,13 @@ class KeyAccess extends AbstractAccess {
   function exists(): bool {
     $key = $this->key;
     if ($key === null) return false;
-    $exists = cl::has($this->dest, $key);
-    if (!$exists) return false;
-    if ($this->allowNull) return true;
-    return cl::get($this->dest, $key) !== null;
+    return cl::has($this->dest, $key);
   }
 
   function available(): bool {
     if (!$this->exists()) return false;
-    $value = $this->get();
+    $value = cl::get($this->dest, $this->key);
+    if ($value === null) return $this->allowNull;
     if ($value === false) return $this->allowFalse;
     if ($value === "") return $this->allowEmpty;
     return true;
diff --git a/wip/php/access/ValueAccess.php b/wip/php/access/ValueAccess.php
index 910e7c8..3088785 100644
--- a/wip/php/access/ValueAccess.php
+++ b/wip/php/access/ValueAccess.php
@@ -32,7 +32,7 @@ class ValueAccess extends AbstractAccess {
 
   function available(): bool {
     if (!$this->exists()) return false;
-    $value = $this->get();
+    $value = $this->dest;
     if ($value === false) return $this->allowFalse;
     if ($value === "") return $this->allowEmpty;
     return true;
diff --git a/wip/schema/input/FormInput.php b/wip/schema/input/FormInput.php
index ce840e9..01b56c2 100644
--- a/wip/schema/input/FormInput.php
+++ b/wip/schema/input/FormInput.php
@@ -3,6 +3,11 @@ namespace nur\sery\wip\schema\input;
 
 #XXX implémenter le renommage de paramètres et faire des méthodes pour
 # construire des querystring et paramètres de formulaires
+use nur\sery\wip\php\access\FormAccess;
+use nur\sery\wip\php\access\IAccess;
+use nur\sery\wip\php\access\KeyAccess;
+use nur\sery\wip\php\access\ShadowAccess;
+
 /**
  * Class FormInput: accès à des paramètres de formulaire (POST ou GET, dans cet
  * ordre)
@@ -13,34 +18,15 @@ namespace nur\sery\wip\schema\input;
 class FormInput extends Input {
   const ALLOW_EMPTY = false;
 
-  function isPresent($key=null): bool {
-    if ($key === null) return false;
-    return array_key_exists($key, $_POST) || array_key_exists($key, $_GET);
+  protected function formAccess($key): IAccess {
+    return new FormAccess($key, [
+      "allow_empty" => $this->allowEmpty,
+    ]);
   }
 
-  function isAvailable($key=null): bool {
-    if ($key === null) return false;
-    if (array_key_exists($key, $_POST)) {
-      return $this->allowEmpty || $_POST[$key] !== "";
-    } elseif (array_key_exists($key, $_GET)) {
-      return $this->allowEmpty || $_GET[$key] !== "";
-    } else {
-      return false;
-    }
-  }
-
-  function get($key=null) {
-    if ($key === null) return null;
-    if (array_key_exists($key, $_POST)) {
-      $value = $_POST[$key];
-      if ($value === "" && !$this->allowEmpty) return null;
-      return $value;
-    } elseif (array_key_exists($key, $_GET)) {
-      $value = $_GET[$key];
-      if ($value === "" && !$this->allowEmpty) return null;
-      return $value;
-    } else {
-      return null;
-    }
+  protected function access($key): IAccess {
+    return $this->keyAccess[$key] ??= new ShadowAccess($this->formAccess($key), new KeyAccess($this->dest, $key, [
+      "allow_empty" => $this->allowEmpty,
+    ]));
   }
 }
diff --git a/wip/schema/input/GetInput.php b/wip/schema/input/GetInput.php
index af4bde8..766c8e5 100644
--- a/wip/schema/input/GetInput.php
+++ b/wip/schema/input/GetInput.php
@@ -1,6 +1,9 @@
 <?php
 namespace nur\sery\wip\schema\input;
 
+use nur\sery\wip\php\access\GetAccess;
+use nur\sery\wip\php\access\IAccess;
+
 /**
  * Class GetInput: accès à des paramètres de formulaire de type GET uniquement
  *
@@ -8,28 +11,9 @@ namespace nur\sery\wip\schema\input;
  * une référence
  */
 class GetInput extends FormInput {
-  function isPresent($key=null): bool {
-    if ($key === null) return false;
-    return array_key_exists($key, $_GET);
-  }
-
-  function isAvailable($key=null): bool {
-    if ($key === null) return false;
-    if (array_key_exists($key, $_GET)) {
-      return $this->allowEmpty || $_GET[$key] !== "";
-    } else {
-      return false;
-    }
-  }
-
-  function get($key=null) {
-    if ($key === null) return null;
-    if (array_key_exists($key, $_GET)) {
-      $value = $_GET[$key];
-      if ($value === "" && !$this->allowEmpty) return null;
-      return $value;
-    } else {
-      return null;
-    }
+  protected function formAccess($key): IAccess {
+    return new GetAccess($key, [
+      "allow_empty" => $this->allowEmpty,
+    ]);
   }
 }
diff --git a/wip/schema/input/Input.php b/wip/schema/input/Input.php
index 86f907a..881adb0 100644
--- a/wip/schema/input/Input.php
+++ b/wip/schema/input/Input.php
@@ -1,7 +1,9 @@
 <?php
 namespace nur\sery\wip\schema\input;
 
-use nur\sery\cl;
+use nur\sery\wip\php\access\IAccess;
+use nur\sery\wip\php\access\KeyAccess;
+use nur\sery\wip\php\access\ValueAccess;
 
 /**
  * Class Input: accès à une valeur
@@ -13,49 +15,52 @@ class Input {
 
   function __construct(&$dest=null, ?array $params=null) {
     $this->dest =& $dest;
-    $allowEmpty = cl::get($params, "allow_empty");
-    if ($allowEmpty === null) $allowEmpty = static::ALLOW_EMPTY;
-    $this->allowEmpty = $allowEmpty;
+    $this->allowEmpty = $params["allow_empty"] ?? static::ALLOW_EMPTY;
   }
 
+  /** @var mixed */
   protected $dest;
 
-  /** tester si la valeur existe sans tenir compte de $allowEmpty */
-  function isPresent($key=null): bool {
-    if ($key === null) return true;
-    $dest = $this->dest;
-    return $dest !== null && array_key_exists($key, $dest);
-  }
-
   /**
    * @var bool comment considérer une chaine vide: "" si allowEmpty, null sinon
    */
   protected $allowEmpty;
 
+  protected ?ValueAccess $valueAccess = null;
+  protected ?array $keyAccess = null;
+
+  protected function access($key): IAccess {
+    if ($key === null) {
+      return $this->valueAccess ??= new ValueAccess($this->dest, [
+        "allow_null" => true,
+        "allow_empty" => $this->allowEmpty,
+      ]);
+    } else {
+      return $this->keyAccess[$key] ??= new KeyAccess($this->dest, $key, [
+        "allow_empty" => $this->allowEmpty,
+      ]);
+    }
+  }
+
+  /** tester si la valeur existe sans tenir compte de $allowEmpty */
+  function isPresent($key=null): bool {
+    return $this->access($key)->exists();
+  }
+
   /** tester si la valeur est disponible en tenant compte de $allowEmpty */
   function isAvailable($key=null): bool {
-    if ($key === null) return true;
-    $dest = $this->dest;
-    if ($dest === null || !array_key_exists($key, $dest)) return false;
-    return $this->allowEmpty || $dest[$key] !== "";
+    return $this->access($key)->available();
   }
 
   function get($key=null) {
-    $dest = $this->dest;
-    if ($key === null) return $dest;
-    if ($dest === null || !array_key_exists($key, $dest)) return null;
-    $value = $dest[$key];
-    if ($value === "" && !$this->allowEmpty) return null;
-    return $value;
+    return $this->access($key)->get();
   }
 
   function set($value, $key=null): void {
-    if ($key === null) $this->dest = $value;
-    else $this->dest[$key] = $value;
+    $this->access($key)->set($value);
   }
 
   function unset($key=null): void {
-    if ($key === null) $this->dest = null;
-    else unset($this->dest[$key]);
+    $this->access($key)->del();
   }
 }
diff --git a/wip/schema/input/PostInput.php b/wip/schema/input/PostInput.php
index 47ea40f..bf720ab 100644
--- a/wip/schema/input/PostInput.php
+++ b/wip/schema/input/PostInput.php
@@ -1,6 +1,9 @@
 <?php
 namespace nur\sery\wip\schema\input;
 
+use nur\sery\wip\php\access\IAccess;
+use nur\sery\wip\php\access\PostAccess;
+
 /**
  * Class PostInput: accès à des paramètres de formulaire de type POST uniquement
  *
@@ -8,28 +11,9 @@ namespace nur\sery\wip\schema\input;
  * une référence
  */
 class PostInput extends FormInput {
-  function isPresent($key=null): bool {
-    if ($key === null) return false;
-    return array_key_exists($key, $_POST);
-  }
-
-  function isAvailable($key=null): bool {
-    if ($key === null) return false;
-    if (array_key_exists($key, $_POST)) {
-      return $this->allowEmpty || $_POST[$key] !== "";
-    } else {
-      return false;
-    }
-  }
-
-  function get($key=null) {
-    if ($key === null) return null;
-    if (array_key_exists($key, $_POST)) {
-      $value = $_POST[$key];
-      if ($value === "" && !$this->allowEmpty) return null;
-      return $value;
-    } else {
-      return null;
-    }
+  protected function formAccess($key): IAccess {
+    return new PostAccess($key, [
+      "allow_empty" => $this->allowEmpty,
+    ]);
   }
 }