Merge pull request #74 from SFDO-Tooling/feature/add-child-count

Add child_count feature

docs/index.md

@@ -610,12 +610,12 @@ The `when` clause can be a Python formula and it will be interpreted as a boolea
 
 The functions below are designed to be used inside of formulas:
 
-The `child_count` variable returns a counter of how many objects from this template were generated
+The `child_index` variable returns a counter of how many objects from this template were generated
 during the execution of the nearest parent template. It resets each time the parent template is
 executed again.
 
   ```
-  child_num: Child number ${{child_count}}
+  child_num: Child number ${{child_index}}
   ```
 
 The `date` function can either coerce a string into a date object for calculations OR generate
@@ -630,7 +630,7 @@ The `relativedelta` [function](https://dateutil.readthedocs.io/en/stable/relativ
 from `dateutil` is available for use in calculations like this:
 
 ```
-${{ date(Date_Established__c) + relativedelta(months=child_count) }}
+${{ date(Date_Established__c) + relativedelta(months=child_index) }}
 ```
 
 ## Macros

snowfakery/data_generator_runtime.py

@@ -342,6 +342,7 @@ def simple_field_vars(self):
         return {
             "id": obj.id if obj else None,
             "count": obj.id if obj else None,
+            "child_index": obj._child_index if obj else None,
             "this": obj,
             "today": interpreter.globals.today,
             "fake": interpreter.faker_template_library,
@@ -390,11 +391,12 @@ class ObjectRow(yaml.YAMLObject):
     yaml_dumper = yaml.SafeDumper
     yaml_tag = "!snowfakery_objectrow"
 
-    __slots__ = ["_tablename", "_values"]
+    __slots__ = ["_tablename", "_values", "_child_index"]
 
-    def __init__(self, tablename, values=()):
+    def __init__(self, tablename, values=(), index=0):
         self._tablename = tablename
         self._values = values
+        self._child_index = index
 
     def __getattr__(self, name):
         try:

snowfakery/data_generator_runtime_object_model.py

@@ -92,7 +92,7 @@ def generate_rows(
             count = self._evaluate_count(context)
             with self.exception_handling(f"Cannot generate {self.name}"):
                 for i in range(count):
-                    rc = self._generate_row(storage, context)
+                    rc = self._generate_row(storage, context, i)
 
         return rc  # return last row
 
@@ -126,10 +126,10 @@ def name(self) -> str:
             name += " (self.nickname)"
         return name
 
-    def _generate_row(self, storage, context: RuntimeContext) -> ObjectRow:
+    def _generate_row(self, storage, context: RuntimeContext, index: int) -> ObjectRow:
         """Generate an individual row"""
         row = {"id": context.generate_id()}
-        sobj = ObjectRow(self.tablename, row)
+        sobj = ObjectRow(self.tablename, row, index)
 
         context.register_object(sobj, self.nickname)
 

tests/test_template_funcs.py

@@ -211,3 +211,16 @@ def test_functions_inline(self, write_row):
         generate(StringIO(yaml), {}, None)
         assert "2012" in write_row.mock_calls[0][1][1]["wedding"]
         assert "1" in write_row.mock_calls[0][1][1]["number"]
+
+    @mock.patch(write_row_path)
+    def test_child_index(self, write_row):
+        yaml = """
+        - object: A
+          friends:
+            - object: B
+              count: 3
+              fields:
+                    num: <<child_index>>
+        """
+        generate(StringIO(yaml), {}, None)
+        assert write_row.mock_calls[3][1][1]["num"] == 2