draft: augment yaml definitions with test schema

generator/config/accumulator/lastN.yaml

@@ -12,7 +12,7 @@ description: |
 arguments:
     - name: input
       type:
-          - resolvesToArray
+          - expression
       description: |
           An expression that resolves to the array from which to return n elements.
     - name: n

generator/config/expression/avg.yaml

@@ -18,11 +18,9 @@ tests:
       pipeline:
           - $project:
                 quizAvg:
-                    $avg:
-                        - $quizzes
+                    $avg: $quizzes
                 labAvg:
-                    $avg:
-                        - $labs
+                    $avg: $labs
                 examAvg:
                     $avg:
                         - $final

generator/config/expression/dateAdd.yaml

@@ -79,6 +79,9 @@ tests:
               purchaseDate:
                   types:
                       - bsonType: Date
+              deliveryDate:
+                  types:
+                      - bsonType: Date
     - name: Adjust for Daylight Savings Time
       link: https://www.mongodb.com/docs/manual/reference/operator/aggregation/dateAdd/#adjust-for-daylight-savings-time
       pipeline:

generator/config/expression/let.yaml

@@ -10,7 +10,7 @@ description: |
 arguments:
     - name: vars
       type:
-          - object
+          - expressionMap
       description: |
           Assignment block for the variables accessible in the in expression. To assign a variable, specify a string for the variable name and assign a valid expression for the value.
           The variable assignments have no meaning outside the in expression, not even within the vars block itself.

generator/config/expression/reduce.yaml

@@ -22,6 +22,14 @@ arguments:
     - name: in
       type:
           - expression
+          - expressionMap
+      syntheticVariables:
+          - name: this
+            description: |
+                The variable that represents the cumulative value of the expression.
+          - name: value
+            description: |
+                The variable that refers to the element being processed.
       description: |
           A valid expression that $reduce applies to each element in the input array in left-to-right order. Wrap the input value with $reverseArray to yield the equivalent of applying the combining expression from right-to-left.
           During evaluation of the in expression, two variables will be available:

generator/config/schema.json

@@ -117,8 +117,10 @@
                             "pipeline",
                             "window",
                             "expression",
+                            "expressionMap",
                             "geometry",
                             "fieldPath",
+                            "unprefixedFieldPath",
                             "timeUnit",
                             "sortSpec",
                             "any",
@@ -228,6 +230,25 @@
                     "$comment": "Skip the name in object encoding and merge the properties of the value into the operator",
                     "type": "boolean",
                     "default": false
+                },
+                "syntheticVariables": {
+                    "$comment": "A list of variables that are automatically made available during evaluation",
+                    "type": "array",
+                    "items": {
+                        "type": "object",
+                        "properties": {
+                            "name": {
+                                "type": "string",
+                                "pattern": "^[$]?[a-zA-Z0-9]*$"
+                            },
+                            "description": {
+                                "type": "string"
+                            }
+                        },
+                        "required": [
+                            "name"
+                        ]
+                    }
                 }
             },
             "required": [

generator/config/stage/group.yaml

@@ -10,6 +10,7 @@ arguments:
     - name: _id
       type:
           - expression
+          - expressionMap
       description: |
           The _id expression specifies the group key. If you specify an _id value of null, or any other constant value, the $group stage returns a single document that aggregates values across all of the input documents.
     - name: field

generator/config/stage/unset.yaml

@@ -10,7 +10,7 @@ description: |
 arguments:
     - name: field
       type:
-          - fieldPath
+          - unprefixedFieldPath
       variadic: array
 tests:
     - name: Remove a Single Field