diff --git a/src/php/time/Time.php b/src/php/time/Time.php
new file mode 100644
index 0000000..955f7c4
--- /dev/null
+++ b/src/php/time/Time.php
@@ -0,0 +1,21 @@
+<?php
+namespace nulib\php\time;
+
+/**
+ * Class Time: une heure allant de 0h à 24h inclus.
+ *
+ * la seule utilisation autorisée de "24h" est comme borne supérieure pour une
+ * plage horaire.
+ */
+class Time {
+  static function with($time): self {
+    if ($time instanceof static) return $time;
+    else return new static($time);
+  }
+
+  static function withn($time): ?self {
+    if ($time === null) return null;
+    elseif ($time instanceof static) return $time;
+    else return new static($time);
+  }
+}
diff --git a/src/php/types/vdate.php b/src/php/types/vdate.php
new file mode 100644
index 0000000..85b1d43
--- /dev/null
+++ b/src/php/types/vdate.php
@@ -0,0 +1,24 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\php\time\Date;
+
+class vdate {
+  static function ensure(&$date): void {
+    $date = Date::with($date);
+  }
+
+  static function ensuren(&$date): void {
+    $date = Date::withn($date);
+  }
+
+  static function with($value): Date {
+    self::ensure($value);
+    return $value;
+  }
+
+  static function withn($value): ?Date {
+    self::ensuren($value);
+    return $value;
+  }
+}
diff --git a/src/php/types/vdatetime.php b/src/php/types/vdatetime.php
new file mode 100644
index 0000000..2f0ecc0
--- /dev/null
+++ b/src/php/types/vdatetime.php
@@ -0,0 +1,24 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\php\time\DateTime;
+
+class vdatetime {
+  static function ensure(&$datetime): void {
+    $datetime = DateTime::with($datetime);
+  }
+
+  static function ensuren(&$datetime): void {
+    $datetime = DateTime::withn($datetime);
+  }
+
+  static function with($value): DateTime {
+    self::ensure($value);
+    return $value;
+  }
+
+  static function withn($value): ?DateTime {
+    self::ensuren($value);
+    return $value;
+  }
+}
diff --git a/src/php/types/vmixed.php b/src/php/types/vmixed.php
new file mode 100644
index 0000000..71630f8
--- /dev/null
+++ b/src/php/types/vmixed.php
@@ -0,0 +1,18 @@
+<?php
+namespace nulib\php\types;
+
+class vmixed {
+  static function ensure(&$mixed): void {
+  }
+
+  static function ensuren(&$mixed): void {
+  }
+
+  static function with($value) {
+    return $value;
+  }
+
+  static function withn($value) {
+    return $value;
+  }
+}
diff --git a/src/php/types/vraw.php b/src/php/types/vraw.php
new file mode 100644
index 0000000..a63d4c1
--- /dev/null
+++ b/src/php/types/vraw.php
@@ -0,0 +1,18 @@
+<?php
+namespace nulib\php\types;
+
+class vraw {
+  static function ensure(&$raw): void {
+  }
+
+  static function ensuren(&$raw): void {
+  }
+
+  static function with($value) {
+    return $value;
+  }
+
+  static function withn($value) {
+    return $value;
+  }
+}
diff --git a/src/php/types/vschema.php b/src/php/types/vschema.php
new file mode 100644
index 0000000..9d5c024
--- /dev/null
+++ b/src/php/types/vschema.php
@@ -0,0 +1,43 @@
+<?php
+namespace nulib\php\types;
+
+/**
+ * Class vschema: gestionsimplifiée de schémas associatifs
+ *
+ * seuls les types simples sont reconnus
+ */
+class vschema {
+  /** @var array types valides */
+  const TYPES = [
+    "rawstring" => vrawstring::class,
+    "string" => vstring::class,
+    "text" => vtext::class,
+    "bool" => vbool::class,
+    "int" => vint::class,
+    "float" => vfloat::class,
+    "array" => varray::class,
+    "func" => vfunc::class,
+    "raw" => vraw::class,
+    "mixed" => vmixed::class,
+    "key" => vkey::class,
+    "pkey" => vpkey::class,
+    "content" => vcontent::class,
+    "datetime" => vdatetime::class,
+    "date" => vdate::class,
+    "time" => vtime::class,
+  ];
+
+  /** indiquer si $value est conforme au schéma */
+  static function check($value, array $schema): bool {
+
+  }
+
+  /**
+   * s'assurer que $value est conforme au schéma
+   * - les clés ne sont pas créées si elles n'existent pas
+   *
+   */
+  static function ensure(&$value, array $schema): void {
+
+  }
+}
diff --git a/src/php/types/vtime.php b/src/php/types/vtime.php
new file mode 100644
index 0000000..1c0f9c6
--- /dev/null
+++ b/src/php/types/vtime.php
@@ -0,0 +1,24 @@
+<?php
+namespace nulib\php\types;
+
+use nulib\php\time\Time;
+
+class vtime {
+  static function ensure(&$time): void {
+    $time = Time::with($time);
+  }
+
+  static function ensuren(&$time): void {
+    $time = Time::withn($time);
+  }
+
+  static function with($value): Time {
+    self::ensure($value);
+    return $value;
+  }
+
+  static function withn($value): ?Time {
+    self::ensuren($value);
+    return $value;
+  }
+}