diff --git a/src/schema/Schema.php b/src/schema/Schema.php
index 02365cb..55f1304 100644
--- a/src/schema/Schema.php
+++ b/src/schema/Schema.php
@@ -17,6 +17,29 @@ use nur\sery\wip\schema\types\tcontent;
 use nur\sery\wip\schema\types\tpkey;
 use nur\sery\wip\schema\types\trawstring;
 
+/**
+ * Class Schema
+ *
+ * @property-read array|IType $type
+ * @property-read mixed $default
+ * @property-read string|null $title
+ * @property-read bool $required
+ * @property-read bool $nullable
+ * @property-read string|array|null $desc
+ * @property-read callable|null $analyzerFunc
+ * @property-read callable|null $extractorFunc
+ * @property-read callable|null $parserFunc
+ * @property-read callable|null $normalizerFunc
+ * @property-read array|null $messages
+ * @property-read callable|null $formatterFunc
+ * @property-read mixed $format
+ * @property-read array $nature
+ * @property-read array|null $schema
+ * @property-read string|int|null $name
+ * @property-read string|array|null $pkey
+ * @property-read string|null $header
+ * @property-read bool|null $computed
+ */
 abstract class Schema implements ArrayAccess {
   /**
    * créer le cas échéant une nouvelle instance de {@link Schema} à partir d'une
@@ -253,6 +276,8 @@ abstract class Schema implements ArrayAccess {
   /** retourner true si le schéma est de nature scalaire */
   function isScalar(?ScalarSchema &$schema=null): bool { return false; }
 
+  abstract protected function newWrapper(): Wrapper;
+
   abstract function getWrapper(&$value=null, $valueKey=null, ?Wrapper &$wrapper=null): Wrapper;
 
   #############################################################################
@@ -272,7 +297,15 @@ abstract class Schema implements ArrayAccess {
     throw AccessException::read_only(null, $offset);
   }
 
-  const _PROPERTY_PKEYS = [];
+  const _PROPERTY_PKEYS = [
+    "analyzerFunc" => "analyzer_func",
+    "extractorFunc" => "extractor_func",
+    "parserFunc" => "parser_func",
+    "normalizerFunc" => "normalizer_func",
+    "formatterFunc" => "formatter_func",
+    "nature" => ["", 0],
+  ];
+
   function __get($name) {
     $pkey = cl::get(static::_PROPERTY_PKEYS, $name, $name);
     return cl::pget($this->definition, $pkey);
diff --git a/src/schema/TODO.md b/src/schema/TODO.md
index 5f50801..46e80ce 100644
--- a/src/schema/TODO.md
+++ b/src/schema/TODO.md
@@ -1,6 +1,5 @@
 # nulib\schema
 
-* instance de WrapperContext directement dans le schéma 
 * plus de {key} ni {orig} dans messages
   * les messages standard ne sont utilisés que s'il n'y a pas de message dans
     l'exception
diff --git a/src/schema/WrapperContext.php b/src/schema/WrapperContext.php
index 5ee0d37..071ed7b 100644
--- a/src/schema/WrapperContext.php
+++ b/src/schema/WrapperContext.php
@@ -5,26 +5,31 @@ use nur\sery\wip\schema\input\Input;
 use nur\sery\wip\schema\types\IType;
 
 class WrapperContext {
-  function __construct(Schema $schema, Wrapper $wrapper, Input $input, $valueKey, Result $result) {
+  function __construct(Schema $schema, Wrapper $wrapper, ?Input $input, $valueKey, Result $result) {
     $this->schema = $schema;
     $this->wrapper = $wrapper;
-    $this->input = $input;
-    $this->result = $result;
+    if ($input !== null) $this->input = $input;
+    $this->valueKey = $valueKey;
     $this->type = null;
+    $this->result = $result;
     $this->origValue = null;
     $this->value = null;
-    $this->valueKey = $valueKey;
   }
 
+  /** schéma de la valeur */
   public Schema $schema;
+  /** instance de Wrapper associé à ce contexte */
   public Wrapper $wrapper;
+  /** source et destination de la valeur */
   public Input $input;
-  public Result $result;
+  /** @var string|int|null clé de la valeur dans le tableau destination */
+  public $valueKey;
+  /** type de la valeur après analyse */
   public ?IType $type;
+  /** résultat de l'analyse de la valeur */
+  public Result $result;
   /** @var mixed */
   public $origValue;
   /** @var mixed */
   public $value;
-  /** @var int|string|null */
-  public $valueKey;
 }
diff --git a/src/schema/_scalar/ScalarSchema.php b/src/schema/_scalar/ScalarSchema.php
index a4c11bf..44e2ac5 100644
--- a/src/schema/_scalar/ScalarSchema.php
+++ b/src/schema/_scalar/ScalarSchema.php
@@ -8,26 +8,6 @@ use nur\sery\wip\schema\Wrapper;
 
 /**
  * Class ScalarSchema
- * 
- * @property-read array|IType $type
- * @property-read mixed $default
- * @property-read string|null $title
- * @property-read bool $required
- * @property-read bool $nullable
- * @property-read string|array|null $desc
- * @property-read callable|null $analyzerFunc
- * @property-read callable|null $extractorFunc
- * @property-read callable|null $parserFunc
- * @property-read callable|null $normalizerFunc
- * @property-read array|null $messages
- * @property-read callable|null $formatterFunc
- * @property-read mixed $format
- * @property-read array $nature
- * @property-read array|null $schema
- * @property-read string|int|null $name
- * @property-read string|array|null $pkey
- * @property-read string|null $header
- * @property-read bool|null $composite
  */
 class ScalarSchema extends Schema {
   /** @var array meta-schema d'un schéma de nature scalaire */
@@ -97,16 +77,4 @@ class ScalarSchema extends Schema {
     if (!($wrapper instanceof ScalarWrapper)) $wrapper = $this->newWrapper();
     return $wrapper->reset($value, $valueKey, $verifix);
   }
-
-  #############################################################################
-  # key & properties
-
-  const _PROPERTY_PKEYS = [
-    "analyzerFunc" => "analyzer_func",
-    "extractorFunc" => "extractor_func",
-    "parserFunc" => "parser_func",
-    "normalizerFunc" => "normalizer_func",
-    "formatterFunc" => "formatter_func",
-    "nature" => ["", 0],
-  ];
 }
diff --git a/src/schema/_scalar/ScalarWrapper.php b/src/schema/_scalar/ScalarWrapper.php
index 0ea9596..5bcb847 100644
--- a/src/schema/_scalar/ScalarWrapper.php
+++ b/src/schema/_scalar/ScalarWrapper.php
@@ -19,35 +19,21 @@ class ScalarWrapper extends Wrapper {
       # c'est une initialisation sans conséquences
       $throw = true;
     }
+    $this->context = new WrapperContext($schema, $this, null, null, new ScalarResult());
     $this->verifix = $verifix;
     $this->throw = $throw ?? false;
-    $this->schema = $schema;
-    $this->result = new ScalarResult();
     $this->reset($value, $valueKey);
     $this->throw = $throw ?? true;
   }
 
   function isScalar(?ScalarWrapper &$wrapper=null): bool { $wrapper = $this; return true; }
 
+  protected WrapperContext $context;
+
   protected bool $verifix;
 
   protected bool $throw;
 
-  /** schéma de cette valeur */
-  protected ScalarSchema $schema;
-
-  /** source et destination de la valeur */
-  protected Input $input;
-
-  /** @var string|int|null clé de la valeur dans le tableau destination */
-  protected $valueKey;
-
-  /** type de la valeur après analyse */
-  protected ?IType $type;
-
-  /** résultat de l'analyse de la valeur */
-  protected ScalarResult $result;
-
   protected function newInput(&$value): Input {
     return new Input($value);
   }
@@ -55,9 +41,9 @@ class ScalarWrapper extends Wrapper {
   function reset(&$value, $valueKey=null, ?bool $verifix=null): Wrapper {
     if ($value instanceof Input) $input = $value;
     else $input = $this->newInput($value);
-    $this->input = $input;
-    $this->valueKey = $valueKey;
-    $this->type = null;
+    $this->context->input = $input;
+    $this->context->valueKey = $valueKey;
+    $this->context->type = null;
     $this->analyze();
     if ($verifix ?? $this->verifix) $this->verifix();
     return $this;
@@ -74,7 +60,8 @@ class ScalarWrapper extends Wrapper {
   }
 
   /** analyser la valeur et résoudre son type */
-  protected function analyze0(WrapperContext $context): int {
+  protected function analyze0(): int {
+    $context = $this->context;
     /** @var ScalarSchema $schema */
     $schema = $context->schema;
     $input = $context->input;
@@ -112,7 +99,7 @@ class ScalarWrapper extends Wrapper {
           $args = $name;
           $name = $key;
         }
-        $type = types::get($schema->nullable, $name, $args, $this->schema->getDefinition());
+        $type = types::get($schema->nullable, $name, $args, $schema->getDefinition());
         if ($firstType === null) $firstType = $type;
         $types[] = $type;
         if ($type->isAvailable($input, $valueKey)) {
@@ -166,17 +153,19 @@ class ScalarWrapper extends Wrapper {
   }
 
   protected function analyze(): int {
-    $schema = $this->schema;
-    $input = $this->input;
-    $valueKey = $this->valueKey;
-    $result = $this->result;
+    $context = $this->context;
+    /** @var ScalarSchema $schema */
+    $schema = $context->schema;
+    $input = $context->input;
+    $valueKey = $context->valueKey;
+    /** @var ScalarResult $result */
+    $result = $context->result;
     $result->reset();
-    $context = new WrapperContext($schema, $this, $input, $valueKey, $result);
 
     /** @var func $analyzerFunc */
     $analyzerFunc = $schema->analyzerFunc;
     if ($analyzerFunc !== null) $what = $analyzerFunc->invoke([$context]);
-    else $what = $this->analyze0($context);
+    else $what = $this->analyze0();
     if ($what !== ref_analyze::STRING) return $what;
 
     $value = $context->value;
@@ -212,20 +201,27 @@ class ScalarWrapper extends Wrapper {
   }
 
   function verifix(?bool $throw=null): bool {
-    $result = $this->result;
-    $valueKey = $this->valueKey;
+    $context = $this->context;
+    /** @var ScalarSchema $schema */
+    $schema = $context->schema;
+    $input = $context->input;
+    $valueKey = $context->valueKey;
+    /** @var ScalarResult $result */
+    $result = $context->result;
+
+
     $verifix = false;
     $modified = false;
     if ($result->resultAvailable) {
       if ($result->null) {
         # forcer la valeur null, parce que la valeur actuelle est peut-être une
         # valeur assimilée à null
-        $this->input->set(null, $valueKey);
+        $input->set(null, $valueKey);
       } elseif ($result->valid && !$result->normalized) {
         $normalizedValue = $result->normalizedValue;
         if ($normalizedValue !== null) {
           # la valeur normalisée est disponible
-          $this->input->set($normalizedValue);
+          $input->set($normalizedValue);
           $result->normalizedValue = null;
           $modified = true;
         } else {
@@ -238,75 +234,80 @@ class ScalarWrapper extends Wrapper {
     }
 
     if ($verifix) {
-      $value = $this->input->get($valueKey);
-      $schema = $this->schema;
+      $value = $input->get($valueKey);
       /** @var func $normalizerFunc */
       $normalizerFunc = $schema->normalizerFunc;
       if ($normalizerFunc !== null) {
-        $context = new WrapperContext($schema, $this, $this->input, $valueKey, $result);
+        $context = new WrapperContext($schema, $this, $input, $valueKey, $result);
         $orig = $value;
         $value = $normalizerFunc->invoke([$orig, $context]);
         $modified = $value !== $orig;
       } else {
-        $modified = $this->type->verifix($value, $result, $this->schema);
+        $modified = $this->type->verifix($value, $result, $schema);
       }
-      if ($result->valid) $this->input->set($value, $valueKey);
+      if ($result->valid) $input->set($value, $valueKey);
     }
     if (!$result->valid) $result->throw($throw ?? $this->throw);
     return $modified;
   }
 
   function getResult(): ScalarResult {
-    return $this->result;
+    /** @var ScalarResult $result */
+    $result = $this->context->result;
+    return $result;
   }
 
   function isPresent(): bool {
-    return $this->result->present;
+    return $this->context->result->present;
   }
 
   function getType(): IType {
-    return $this->type;
+    return $this->context->type;
   }
 
   function isAvailable(): bool {
-    return $this->result->available;
+    return $this->context->result->available;
   }
 
   function isValid(): bool {
-    return $this->result->valid;
+    return $this->context->result->valid;
   }
 
   function isNormalized(): bool {
-    return $this->result->normalized;
+    return $this->context->result->normalized;
   }
 
   function get($default=null) {
-    if ($this->result->available) return $this->input->get($this->valueKey);
+    $context = $this->context;
+    if ($context->result->available) return $context->input->get($context->valueKey);
     else return $default;
   }
 
   function set($value, ?bool $verifix=null): ScalarWrapper {
-    $this->input->set($value, $this->valueKey);
+    $context = $this->context;
+    $context->input->set($value, $context->valueKey);
     $this->analyze();
     if ($verifix ?? $this->verifix) $this->verifix();
     return $this;
   }
 
   function unset(?bool $verifix=null): ScalarWrapper {
-    $this->input->unset($this->valueKey);
+    $context = $this->context;
+    $context->input->unset($context->valueKey);
     $this->analyze();
     if ($verifix ?? $this->verifix) $this->verifix();
     return $this;
   }
 
   function format($format=null): string {
-    $value = $this->input->get($this->valueKey);
+    $context = $this->context;
+    $value = $context->input->get($context->valueKey);
     /** @var func $formatterFunc */
-    $formatterFunc = $this->schema->formatterFunc;
+    $formatterFunc = $context->schema->formatterFunc;
     if ($formatterFunc !== null) {
       # la fonction formatter n'a pas forcément accès au format de la définition
       # le lui fournir ici
-      $format ??= $this->schema->format;
+      $format ??= $context->schema->format;
       return $formatterFunc->invoke([$value, $format]);
     } else {
       # on assume que le type a été initialisé avec le format de la définition