Refactoring

image_prediction/image_extractor/extractors/parsable.py

@@ -147,27 +147,35 @@ def make_eithered_image_metadata_pair(image: Either, metadata: Either) -> Either
     def context(value):
         return {"reason": value, "metadata": metadata.either(bottom, identity)}
 
-    # What is most readable?
+    # Explicitly we are doing the following. (1) and (2) are equivalent.
 
-    # 1)
-    # return Either.apply(make_image_metadata_pair).to_arguments(image, metadata).either(left(context), right(identity))
-
-    # 2)
-    # m (a -> b -> c) -> m a -> m b -> m c
-    # return Right(make_image_metadata_pair).amap(image).amap(metadata).either(left(context), right(identity))
-
-    # 3)
     # a := Image
     # b := Metadata
     # c := ImageMetadataPair
-    return (
-        image.bind(right(make_image_metadata_pair))  # m a >>= m (a -> b -> c) -> m (b -> c)
-        .amap(metadata)  # m (b -> c) <*> m b -> m c
-        .either(
-            left(context),
-            right(identity),
-        )
-    )
+
+    # 1)
+    # return (
+    #     Right(make_image_metadata_pair)  # m (a -> b -> c)
+    #     .amap(image)  # m (a -> b -> c) $ m a = m (b -> c)
+    #     .amap(metadata)  # m (b -> c) $ m b = m c
+    #     .either(
+    #         left(context),
+    #         right(identity),
+    #     )
+    # )
+
+    # 2)
+    # return (
+    #     image.bind(right(make_image_metadata_pair))  # m a >>= m (a -> b -> c) = m (b -> c)
+    #     .amap(metadata)  # m (b -> c) <*> m b = m c
+    #     .either(
+    #         left(context),
+    #         right(identity),
+    #     )
+    # )
+
+    # Syntactic sugar variant:
+    return Either.apply(make_image_metadata_pair).to_arguments(image, metadata).either(left(context), right(identity))
 
 
 @curry(2)