Merge pull request #48 from nodestream-proj/feature/multi-interpretat…

…ion-switch

Allow Switch Interpretation to Apply Many Interpretations In Each Branch

docs/docs/reference/interpretations.md

@@ -50,5 +50,5 @@ The switch interpretation allows you to define multiple interpretations that wil
 | Parameter Name 	| Required? 	| Type       	| Description                                                                                                                                                                                                	|
 |----------------	|-----------	|------------	|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------	|
 | switch_on     	| Yes       	| ValueProvider 	| The value provider that will be evaluated for each source node. The value of the value provider will be used to determine which interpretation to apply.        	|
-| interpretations  	| Yes        	| Dictionary 	| Contains the interpretations that will be applied. The keys represent the values of the `switch_on` parameter. The values represent the interpretations that will be applied. 	|
+| interpretations  	| Yes        	| Dictionary 	| Contains the interpretations that will be applied. The keys represent the values of the `switch_on` parameter. The values represent the interpretations that will be applied. Each value may also be a list of interpretations.	|
 | default  	| No        	| Dictionary 	| Contains the default interpretation that will be applied if no interpretation has the same value as the value of the `switch_on` parameter. 	|

nodestream/interpreting/interpretations/switch_interpretation.py

@@ -1,4 +1,4 @@
-from typing import Any, Dict
+from typing import Any, Dict, List
 
 from ...pipeline.value_providers import (
     ProviderContext,
@@ -29,6 +29,16 @@ class SwitchInterpretation(
         "fail_on_unhandled",
     )
 
+    @staticmethod
+    def guarantee_interpretation_list_from_file_data(file_data) -> List[Interpretation]:
+        if isinstance(file_data, list):
+            return [
+                Interpretation.from_file_data(**interpretation)
+                for interpretation in file_data
+            ]
+
+        return [Interpretation.from_file_data(**file_data)]
+
     def __init__(
         self,
         switch_on: StaticValueOrValueProvider,
@@ -39,28 +49,34 @@ def __init__(
     ):
         self.switch_on = ValueProvider.guarantee_value_provider(switch_on)
         self.interpretations = {
-            field_value: Interpretation.from_file_data(**interpretation)
+            field_value: self.guarantee_interpretation_list_from_file_data(
+                interpretation
+            )
             for field_value, interpretation in cases.items()
         }
-        self.default = Interpretation.from_file_data(**default) if default else None
+        self.default = (
+            self.guarantee_interpretation_list_from_file_data(default)
+            if default
+            else None
+        )
         self.normalization = normalization or {}
         self.fail_on_unhandled = fail_on_unhandled
 
     def all_subordinate_components(self):
-        yield from self.interpretations.values()
+        for child in self.interpretations.values():
+            yield from child
         if self.default:
-            yield self.default
+            yield from self.default
 
     def interpret(self, context: ProviderContext):
-        value_to_look_for = self.switch_on.normalize_single_value(
-            context, **self.normalization
-        )
-        if value_to_look_for not in self.interpretations:
-            if self.default:
-                self.default.interpret(context)
-                return
+        key = self.switch_on.normalize_single_value(context, **self.normalization)
+        interpretations = self.interpretations.get(key, self.default)
+
+        if interpretations is None:
             if self.fail_on_unhandled:
-                raise UnhandledBranchError(value_to_look_for)
+                raise UnhandledBranchError(key)
             else:
-                return
-        return self.interpretations[value_to_look_for].interpret(context)
+                interpretations = []
+
+        for interpretation in interpretations:
+            interpretation.interpret(context)

tests/unit/interpreting/interpretations/test_switch_interpretation.py

@@ -42,3 +42,15 @@ def test_missing_without_default_without_error(blank_context):
     properties = blank_context.desired_ingest.source.properties
     assert_that(properties, not_(has_entry("success", True)))
     assert_that(properties, not_(has_entry("random", True)))
+
+
+def test_switch_with_multiple_interpretations(blank_context):
+    subject = SwitchInterpretation(
+        switch_on="foo",
+        cases={"foo": [INTERPRETATION_USED_AS_HIT, INTERPRETATION_FOR_RANDOM]},
+        fail_on_unhandled=False,
+    )
+    subject.interpret(blank_context)
+    properties = blank_context.desired_ingest.source.properties
+    assert_that(properties, has_entry("success", True))
+    assert_that(properties, has_entry("random", True))