lib/serialization: prepare to collect errors and customize reactions to them

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/serialization/serialization.nit b/lib/serialization/serialization.nit
index ca60d7a..d120254 100644 (file)
--- a/lib/serialization/serialization.nit
+++ b/lib/serialization/serialization.nit
@@ -88,7 +88,7 @@ end
 # Abstract deserialization service
 #
 # After initialization of one of its sub-classes, call `deserialize`
-interface Deserializer
+abstract class Deserializer
        # Main method of this class, returns a Nit object
        fun deserialize: nullable Object is abstract
 
@@ -110,6 +110,48 @@ interface Deserializer
                print "Error: doesn't know how to deserialize class \"{class_name}\""
                abort
        end
+
+       # Should `self` keep trying to deserialize an object after an error?
+       #
+       # This behavior takes effect after each attribute deserialization with
+       # errors such as a missing attribute or the value is of the wrong type.
+       # If `keep_going`, the attribute will be skipped but the engine will
+       # deserialize the next attribute.
+       # If `not keep_going`, the engine stops deserializing right away.
+       #
+       # When at `true`, this may cause the accumulation of a lot of entries in `errors`.
+       #
+       # Default at `true`.
+       var keep_going: nullable Bool is writable
+
+       # Errors encountered in the last call to `deserialize`
+       var errors = new Array[Error]
+end
+
+# Deserialization got wrong attribute names
+class AttributeTypeError
+       super Error
+
+       # Parent object of the problematic attribute
+       var receiver: Object
+
+       # Name of the problematic attribute in `receiver`
+       var attribute_name: String
+
+       # Deserialized object that isn't of the `expected_type`
+       var attribute: nullable Object
+
+       # Name of the type expected for `attribute`
+       var expected_type: String
+
+       redef fun to_s
+       do
+               var attribute = attribute
+               var found_type = if attribute != null then attribute.class_name else "null"
+
+               return "Deserialization Error: {
+               }Wrong type on `{receiver.class_name}::{attribute_name}` expected `{expected_type}`, got `{found_type}`"
+       end
 end
 
 # Instances of this class can be passed to `Serializer::serialize`