diff --git a/src/php/types/varray.php b/src/php/types/varray.php
new file mode 100644
index 0000000..8f517e4
--- /dev/null
+++ b/src/php/types/varray.php
@@ -0,0 +1,14 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\cl;
+
+class varray {
+  static function ensure_array(&$array): void {
+    if (!is_array($array)) $array = cl::with($array);
+  }
+
+  static function ensure_narray(&$array): void {
+    if ($array !== null) varray::ensure_array($array);
+  }
+}
diff --git a/src/php/types/vbool.php b/src/php/types/vbool.php
new file mode 100644
index 0000000..f4c9167
--- /dev/null
+++ b/src/php/types/vbool.php
@@ -0,0 +1,46 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\schema\types\tbool;
+
+class vbool {
+  /** liste de valeurs chaines à considérer comme 'OUI' */
+  public const YES_VALUES = [
+    "true", "vrai", "yes", "oui",
+    "t", "v", "y", "o", "1",
+  ];
+  /** liste de valeurs chaines à considérer comme 'NON' */
+  public const NO_VALUES = [
+    "false", "faux", "non", "no",
+    "f", "n", "0",
+  ];
+
+  /** Vérifier si $value est 'OUI' */
+  static final function is_yes(?string $value): bool {
+    if ($value === null) return false;
+    $value = strtolower(trim($value));
+    if (in_array($value, self::YES_VALUES, true)) return true;
+    // n'importe quelle valeur numérique
+    if (is_numeric($value)) return $value != 0;
+    return false;
+  }
+
+  /** Vérifier si $value est 'NON' */
+  static final function is_no(?string $value): bool {
+    if ($value === null) return true;
+    $value = strtolower(trim($value));
+    return in_array($value, self::NO_VALUES, true);
+  }
+
+  static function ensure_bool(&$bool): void {
+    if (is_string($bool)) {
+      if (self::is_yes($bool)) $bool = true;
+      elseif (self::is_no($bool)) $bool = false;
+    }
+    if (!is_bool($bool)) $bool = boolval($bool);
+  }
+
+  static function ensure_nbool(&$bool): void {
+    if ($bool !== null) self::ensure_bool($bool);
+  }
+}
diff --git a/src/php/types/vcontent.php b/src/php/types/vcontent.php
new file mode 100644
index 0000000..80de469
--- /dev/null
+++ b/src/php/types/vcontent.php
@@ -0,0 +1,13 @@
+<?php
+namespace nulib\php\types;
+
+class vcontent {
+  static function ensure_content(&$content): void {
+    if ($content === null || $content === false) $content = [];
+    elseif (!is_string($content) && !is_array($content)) $content = strval($content);
+  }
+
+  static function ensure_ncontent(&$content): void {
+    if ($content !== null) self::ensure_content($content);
+  }
+}
diff --git a/src/php/types/vfloat.php b/src/php/types/vfloat.php
new file mode 100644
index 0000000..b4d53e0
--- /dev/null
+++ b/src/php/types/vfloat.php
@@ -0,0 +1,12 @@
+<?php
+namespace nulib\php\types;
+
+class vfloat {
+  static function ensure_float(&$float): void {
+    if (!is_float($float)) $float = floatval($float);
+  }
+
+  static function ensure_nfloat(&$float): void {
+    if ($float !== null) self::ensure_float($float);
+  }
+}
diff --git a/src/php/types/vfunc.php b/src/php/types/vfunc.php
new file mode 100644
index 0000000..25ea6dc
--- /dev/null
+++ b/src/php/types/vfunc.php
@@ -0,0 +1,14 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\php\func;
+
+class vfunc {
+  static function ensure_func(&$func): void {
+    $func = func::ensure($func);
+  }
+
+  static function ensure_nfunc(&$func): void {
+    if ($func !== null) self::ensure_func($func);
+  }
+}
diff --git a/src/php/types/vint.php b/src/php/types/vint.php
new file mode 100644
index 0000000..7a6a35a
--- /dev/null
+++ b/src/php/types/vint.php
@@ -0,0 +1,12 @@
+<?php
+namespace nulib\php\types;
+
+class vint {
+  static function ensure_int(&$int): void {
+    if (!is_int($int)) $int = intval($int);
+  }
+
+  static function ensure_nint(&$int): void {
+    if ($int !== null) self::ensure_int($int);
+  }
+}
diff --git a/src/php/types/vkey.php b/src/php/types/vkey.php
new file mode 100644
index 0000000..9c4acc5
--- /dev/null
+++ b/src/php/types/vkey.php
@@ -0,0 +1,14 @@
+<?php
+namespace nulib\php\types;
+
+class vkey {
+  static function ensure_key(&$key): void {
+    if ($key === null) $key = "";
+    elseif ($key === false) $key = 0;
+    elseif (!is_string($key) && !is_int($key)) $key = strval($key);
+  }
+
+  static function ensure_nkey(&$key): void {
+    if ($key !== null) self::ensure_key($key);
+  }
+}
diff --git a/src/php/types/vpkey.php b/src/php/types/vpkey.php
new file mode 100644
index 0000000..c0841cb
--- /dev/null
+++ b/src/php/types/vpkey.php
@@ -0,0 +1,20 @@
+<?php
+namespace nulib\php\types;
+
+class vpkey {
+  static function ensure_pkey(&$pkey): void {
+    if ($pkey === null) $pkey = "";
+    elseif ($pkey === false) $pkey = 0;
+    elseif (!is_string($pkey) && !is_int($pkey) && !is_array($pkey)) $pkey = strval($pkey);
+    if (is_array($pkey)) {
+      foreach ($pkey as &$key) {
+        vkey::ensure_key($key);
+      };
+      unset($key);
+    }
+  }
+
+  static function ensure_npkey(&$pkey): void {
+    if ($pkey !== null) self::ensure_pkey($pkey);
+  }
+}
diff --git a/src/php/types/vrawstring.php b/src/php/types/vrawstring.php
new file mode 100644
index 0000000..7650c78
--- /dev/null
+++ b/src/php/types/vrawstring.php
@@ -0,0 +1,21 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\str;
+
+class vrawstring {
+  /** @var bool faut-il trimmer la valeur */
+  const TRIM = false;
+  /** @var bool faut-il normaliser les caractères fin de ligne */
+  const NORM_NL = false;
+
+  static function ensure_string(&$string): void {
+    if (!is_string($string)) $string = strval($string);
+    if (static::TRIM) $string = trim($string);
+    if (static::NORM_NL) $string = str::norm_nl($string);
+  }
+
+  static function ensure_nstring(&$string): void {
+    if ($string !== null) self::ensure_string($string);
+  }
+}
diff --git a/src/php/types/vstring.php b/src/php/types/vstring.php
new file mode 100644
index 0000000..6b0431b
--- /dev/null
+++ b/src/php/types/vstring.php
@@ -0,0 +1,6 @@
+<?php
+namespace nulib\php\types;
+
+class vstring extends vrawstring {
+  const TRIM = true;
+}
diff --git a/src/php/types/vtext.php b/src/php/types/vtext.php
new file mode 100644
index 0000000..afe4c9f
--- /dev/null
+++ b/src/php/types/vtext.php
@@ -0,0 +1,8 @@
+<?php
+namespace nulib\php\types;
+
+class vtext extends vrawstring {
+  const TRIM = true;
+
+  const NORM_NL = true;
+}
diff --git a/src/schema/Schema.php b/src/schema/Schema.php
index 2b96626..67badaf 100644
--- a/src/schema/Schema.php
+++ b/src/schema/Schema.php
@@ -4,6 +4,11 @@ namespace nulib\schema;
 use ArrayAccess;
 use nulib\AccessException;
 use nulib\cl;
+use nulib\php\types\varray;
+use nulib\php\types\vbool;
+use nulib\php\types\vcontent;
+use nulib\php\types\vfunc;
+use nulib\php\types\vpkey;
 use nulib\ref\schema\ref_schema;
 use nulib\ref\schema\ref_types;
 use nulib\schema\_assoc\AssocSchema;
@@ -177,7 +182,7 @@ abstract class Schema implements ArrayAccess {
     $definition["nullable"] = $nullable;
     # nature
     $nature = $definition[""];
-    tarray::ensure_array($nature);
+    varray::ensure_array($nature);
     $natureMetaschema ??= ref_schema::NATURE_METASCHEMA;
     foreach (array_keys($natureMetaschema) as $key) {
       if (!array_key_exists($key, $nature)) {
@@ -191,7 +196,7 @@ abstract class Schema implements ArrayAccess {
     $header = $definition["header"];
     if ($name === null) $name = $definitionKey;
     trawstring::ensure_nstring($name);
-    tpkey::ensure_npkey($pkey);
+    vpkey::ensure_npkey($pkey);
     trawstring::ensure_nstring($header);
     if ($pkey === null) $pkey = $name;
     if ($header === null) $header = $name;
@@ -199,18 +204,18 @@ abstract class Schema implements ArrayAccess {
     $definition["pkey"] = $pkey;
     $definition["header"] = $header;
     # autres éléments
-    tarray::ensure_narray($definition["schema"]);
+    varray::ensure_narray($definition["schema"]);
     trawstring::ensure_nstring($definition["title"]);
-    tbool::ensure_bool($definition["required"]);
-    tbool::ensure_bool($definition["nullable"]);
-    tcontent::ensure_ncontent($definition["desc"]);
-    tfunc::ensure_nfunc($definition["analyzer_func"]);
-    tfunc::ensure_nfunc($definition["extractor_func"]);
-    tfunc::ensure_nfunc($definition["parser_func"]);
-    tfunc::ensure_nfunc($definition["normalizer_func"]);
-    tarray::ensure_narray($definition["messages"]);
-    tfunc::ensure_nfunc($definition["formatter_func"]);
-    tbool::ensure_nbool($definition["computed"]);
+    vbool::ensure_bool($definition["required"]);
+    vbool::ensure_bool($definition["nullable"]);
+    vcontent::ensure_ncontent($definition["desc"]);
+    vfunc::ensure_nfunc($definition["analyzer_func"]);
+    vfunc::ensure_nfunc($definition["extractor_func"]);
+    vfunc::ensure_nfunc($definition["parser_func"]);
+    vfunc::ensure_nfunc($definition["normalizer_func"]);
+    varray::ensure_narray($definition["messages"]);
+    vfunc::ensure_nfunc($definition["formatter_func"]);
+    vbool::ensure_nbool($definition["computed"]);
 
     switch ($nature[0] ?? null) {
     case "assoc":
diff --git a/src/schema/types/tarray.php b/src/schema/types/tarray.php
index d53cddc..ace3578 100644
--- a/src/schema/types/tarray.php
+++ b/src/schema/types/tarray.php
@@ -47,14 +47,6 @@ class tarray extends _tstring {
     return $params;
   }
 
-  static function ensure_array(&$array): void {
-    if (!is_array($array)) $array = cl::with($array);
-  }
-
-  static function ensure_narray(&$array): void {
-    if ($array !== null) self::ensure_array($array);
-  }
-
   function getClass(): string {
     return "array";
   }
diff --git a/src/schema/types/tbool.php b/src/schema/types/tbool.php
index 0f9b0db..3726dfd 100644
--- a/src/schema/types/tbool.php
+++ b/src/schema/types/tbool.php
@@ -2,6 +2,7 @@
 namespace nulib\schema\types;
 
 use nulib\cl;
+use nulib\php\types\vbool;
 use nulib\schema\_scalar\ScalarSchema;
 use nulib\schema\input\Input;
 use nulib\schema\Result;
@@ -14,47 +15,6 @@ class tbool extends _tformatable {
 
   const ALIASES = ["boolean"];
 
-  /** liste de valeurs chaines à considérer comme 'OUI' */
-  const YES_VALUES = [
-    "true", "vrai", "yes", "oui",
-    "t", "v", "y", "o", "1",
-  ];
-
-  /** liste de valeurs chaines à considérer comme 'NON' */
-  const NO_VALUES = [
-    "false", "faux", "non", "no",
-    "f", "n", "0",
-  ];
-
-  /** Vérifier si $value est 'OUI' */
-  static final function is_yes(?string $value): bool {
-    if ($value === null) return false;
-    $value = strtolower(trim($value));
-    if (in_array($value, self::YES_VALUES, true)) return true;
-    // n'importe quelle valeur numérique
-    if (is_numeric($value)) return $value != 0;
-    return false;
-  }
-
-  /** Vérifier si $value est 'NON' */
-  static final function is_no(?string $value): bool {
-    if ($value === null) return true;
-    $value = strtolower(trim($value));
-    return in_array($value, self::NO_VALUES, true);
-  }
-
-  static function ensure_bool(&$bool): void {
-    if (is_string($bool)) {
-      if (self::is_yes($bool)) $bool = true;
-      elseif (self::is_no($bool)) $bool = false;
-    }
-    if (!is_bool($bool)) $bool = boolval($bool);
-  }
-
-  static function ensure_nbool(&$bool): void {
-    if ($bool !== null) self::ensure_bool($bool);
-  }
-
   function getClass(): string {
     return "bool";
   }
@@ -92,8 +52,8 @@ class tbool extends _tformatable {
   }
 
   function parse(string $value) {
-    if (self::is_yes($value)) return true;
-    elseif (self::is_no($value)) return false;
+    if (vbool::is_yes($value)) return true;
+    elseif (vbool::is_no($value)) return false;
     throw new ValueException("une valeur booléenne est attendue");
   }
 
diff --git a/src/schema/types/tcontent.php b/src/schema/types/tcontent.php
index b775cdf..947f356 100644
--- a/src/schema/types/tcontent.php
+++ b/src/schema/types/tcontent.php
@@ -9,15 +9,6 @@ use nulib\schema\Schema;
 abstract class tcontent extends _tunion {
   const NAME = "content";
 
-  static function ensure_content(&$content): void {
-    if ($content === null || $content === false) $content = [];
-    elseif (!is_string($content) && !is_array($content)) $content = strval($content);
-  }
-
-  static function ensure_ncontent(&$content): void {
-    if ($content !== null) self::ensure_content($content);
-  }
-
   function getClass(): string {
     return "string|array";
   }
diff --git a/src/schema/types/tfloat.php b/src/schema/types/tfloat.php
index 51fae89..dbd191a 100644
--- a/src/schema/types/tfloat.php
+++ b/src/schema/types/tfloat.php
@@ -11,14 +11,6 @@ class tfloat extends _tformatable {
 
   const ALIASES = ["flt", "double", "dbl"];
 
-  static function ensure_float(&$float): void {
-    if (!is_float($float)) $float = floatval($float);
-  }
-
-  static function ensure_nfloat(&$float): void {
-    if ($float !== null) self::ensure_float($float);
-  }
-
   function getClass(): string {
     return "float";
   }
diff --git a/src/schema/types/tfunc.php b/src/schema/types/tfunc.php
index e846049..636eeff 100644
--- a/src/schema/types/tfunc.php
+++ b/src/schema/types/tfunc.php
@@ -13,14 +13,6 @@ class tfunc extends _tsimple {
 
   const ALIASES = ["function", "callable"];
 
-  static function ensure_func(&$func): void {
-    $func = func::ensure($func);
-  }
-
-  static function ensure_nfunc(&$func): void {
-    if ($func !== null) self::ensure_func($func);
-  }
-
   function getClass(): string {
     return func::class;
   }
diff --git a/src/schema/types/tint.php b/src/schema/types/tint.php
index 1f3a5ae..d1b7f93 100644
--- a/src/schema/types/tint.php
+++ b/src/schema/types/tint.php
@@ -11,14 +11,6 @@ class tint extends _tformatable {
 
   const ALIASES = ["integer"];
 
-  static function ensure_int(&$int): void {
-    if (!is_int($int)) $int = intval($int);
-  }
-
-  static function ensure_nint(&$int): void {
-    if ($int !== null) self::ensure_int($int);
-  }
-
   //const INT_PATTERN = '/^[-+]?[0-9]+(?:\.[0-9]*)?$/';
 
   function getClass(): string {
diff --git a/src/schema/types/tkey.php b/src/schema/types/tkey.php
index 0650f54..c1809b6 100644
--- a/src/schema/types/tkey.php
+++ b/src/schema/types/tkey.php
@@ -8,16 +8,6 @@ use nulib\schema\Schema;
 class tkey extends _tunion {
   const NAME = "key";
 
-  static function ensure_key(&$key): void {
-    if ($key === null) $key = "";
-    elseif ($key === false) $key = 0;
-    elseif (!is_string($key) && !is_int($key)) $key = strval($key);
-  }
-
-  static function ensure_nkey(&$key): void {
-    if ($key !== null) self::ensure_key($key);
-  }
-
   function getClass(): string {
     return "string|int";
   }
diff --git a/src/schema/types/tpkey.php b/src/schema/types/tpkey.php
index fa09fd5..651e21b 100644
--- a/src/schema/types/tpkey.php
+++ b/src/schema/types/tpkey.php
@@ -1,6 +1,7 @@
 <?php
 namespace nulib\schema\types;
 
+use nulib\php\types\vkey;
 use nulib\schema\_scalar\ScalarSchema;
 use nulib\schema\Result;
 use nulib\schema\Schema;
@@ -8,21 +9,6 @@ use nulib\schema\Schema;
 class tpkey extends _tunion {
   const NAME = "pkey";
 
-  static function ensure_pkey(&$pkey): void {
-    if ($pkey === null) $pkey = "";
-    elseif ($pkey === false) $pkey = 0;
-    elseif (!is_string($pkey) && !is_int($pkey) && !is_array($pkey)) $pkey = strval($pkey);
-    if (is_array($pkey)) {
-      foreach ($pkey as &$key) {
-        tkey::ensure_key($key);
-      }; unset($key);
-    }
-  }
-
-  static function ensure_npkey(&$pkey): void {
-    if ($pkey !== null) self::ensure_pkey($pkey);
-  }
-
   function getClass(): string {
     return "string|int|array";
   }
diff --git a/src/schema/types/trawstring.php b/src/schema/types/trawstring.php
index 2cf7f4e..1cd4f92 100644
--- a/src/schema/types/trawstring.php
+++ b/src/schema/types/trawstring.php
@@ -9,16 +9,6 @@ use nulib\str;
 class trawstring extends _tstring {
   const NAME = "rawstring";
 
-  static function ensure_string(&$string): void {
-    if (!is_string($string)) $string = strval($string);
-    if (static::TRIM) $string = trim($string);
-    if (static::NORM_NL) $string = str::norm_nl($string);
-  }
-
-  static function ensure_nstring(&$string): void {
-    if ($string !== null) self::ensure_string($string);
-  }
-
   function getClass(): string {
     return "string";
   }