+ @Tranient for serialization

docs/OOP.md

@@ -857,6 +857,19 @@ Private fields are visible only _inside the class instance_:
     void
     >>> void
 
+### Transient fields
+
+You can mark a field or a constructor parameter as transient using the `@Transient` attribute. Transient members are ignored during serialization (Lynon and JSON) and are also excluded from structural equality (`==`) checks.
+
+```lyng
+class Session(@Transient val token, val userId) {
+    @Transient var lastAccess = time.now()
+    var data = Map()
+}
+```
+
+For more details on how transient fields behave during restoration, see the [Serialization Guide](serialization.md).
+
 ### Protected members
 
 Protected members are available to the declaring class and all of its transitive subclasses (including via MI). Additionally, an ancestor class can access a `protected` member of its descendant if the ancestor also defines or inherits a member with the same name (i.e., it is an override of something the ancestor knows about). 

docs/json_and_kotlin_serialization.md

@@ -20,7 +20,18 @@ Simple classes serialization is supported:
     assertEquals( "{\"foo\":1,\"bar\":2}", Point(1,2).toJsonString() )
     >>> void
 
-Note that mutable members are serialized:
+Note that mutable members are serialized by default. You can exclude any member (including constructor parameters) from JSON serialization using the `@Transient` attribute:
+
+    import lyng.serialization
+    
+    class Point2(@Transient val foo, val bar) {
+        @Transient var reason = 42
+        var visible = 100
+    }
+    assertEquals( "{\"bar\":2,\"visible\":100}", Point2(1,2).toJsonString() )
+    >>> void
+
+Note that if you override json serialization:
 
     import lyng.serialization
     

docs/serialization.md

@@ -20,20 +20,37 @@ It is as simple as:
     assert( text.length > encodedBits.toBuffer().size )
     >>> void
 
-Any class you create is serializable by default; lynon serializes first constructor fields, then any `var` member fields:
+Any class you create is serializable by default; lynon serializes first constructor fields, then any `var` member fields.
 
-    import lyng.serialization
+## Transient Fields
 
-    class Point(x,y)
+Sometimes you have fields that should not be serialized, for example, temporary caches, secret data, or derived values that are recomputed in `init` blocks. You can mark such fields with the `@Transient` attribute:
 
-    val p = Lynon.decode( Lynon.encode( Point(5,6) ) )
+```lyng
+class MyData(@Transient val tempSecret, val publicData) {
+    @Transient var cachedValue = 0
+    var persistentValue = 42
     
-    assertEquals( 5, p.x )
-    assertEquals( 6, p.y )
-    >>> void
+    init {
+        // cachedValue can be recomputed here upon deserialization
+        cachedValue = computeCache(publicData)
+    }
+}
+```
 
+Transient fields:
+- Are **omitted** from Lynon binary streams.
+- Are **omitted** from JSON output (via `toJson`).
+- Are **ignored** during structural equality checks (`==`).
+- If a transient constructor parameter has a **default value**, it will be restored to that default value during deserialization. Otherwise, it will be `null`.
+- Class body fields marked as `@Transient` will keep their initial values (or values assigned in `init`) after deserialization.
 
-just as expected.
+## Serialization of Objects and Classes
+
+- **Singleton Objects**: `object` declarations are serializable by name. Their state (mutable fields) is also serialized and restored, respecting `@Transient`.
+- **Classes**: Class objects themselves can be serialized. They are serialized by their full qualified name. When converted to JSON, a class object includes its public static fields (excluding those marked `@Transient`).
+
+## Custom Serialization
 
 Important is to understand that normally `Lynon.decode` wants [BitBuffer], as `Lynon.encode` produces. If you have the regular [Buffer], be sure to convert it:
 

docs/whats_new.md

@@ -171,6 +171,21 @@ settings["theme"] ?= "dark"
 
 The operator returns the final value of the receiver (the original value if it was not `null`, or the new value if the assignment occurred).
 
+### Transient Attribute (`@Transient`)
+The `@Transient` attribute can now be applied to class fields, constructor parameters, and static fields to exclude them from serialization.
+
+```lyng
+class MyData(@Transient val tempSecret, val publicData) {
+    @Transient var cachedValue = 0
+    var persistentValue = 42
+}
+```
+
+Key features:
+- **Serialization**: Transient members are omitted from both Lynon binary streams and JSON output.
+- **Structural Equality**: Transient fields are automatically ignored during `==` equality checks.
+- **Deserialization**: Transient constructor parameters with default values are correctly restored to those defaults upon restoration.
+
 ## Tooling and Infrastructure
 
 ### CLI: Formatting Command