feat: add IMPORT FROM MAPPING and EXPORT TO MAPPING microflow actions

Full read+write support for import/export mapping actions in microflows:

  $Pet = IMPORT FROM MAPPING Module.IMM($JsonString);
  $Json = EXPORT TO MAPPING Module.EMM($Pet);

Import assignment is optional (persistent entities store directly to DB).

Implementation: grammar rules, AST types, visitor, executor builder
(auto-resolves entity type and single/list from JSON structure), BSON
writer (ImportMappingCall with ResultHandling, StringExport with
MappingRequestHandling), and BSON parser for DESCRIBE roundtrip.

Also updates: MDL quick reference, feature matrix, help topics (rest,
integration), skill doc, docs-site REST integration page, and doctype
test examples with 3 executable microflows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ako

.claude/skills/mendix/rest-call-from-json.md

@@ -133,6 +133,46 @@ END;
 
 ---
 
+## Step 5 — Import/Export Mapping in Microflows (Optional)
+
+Instead of using `RETURNS MAPPING` on a REST CALL, you can use standalone import/export mapping actions. This is useful when you already have a JSON string and want to map it to entities, or when you want to serialize entities back to JSON.
+
+### Import from mapping
+
+Applies an import mapping to a string variable (JSON content) to produce entity objects:
+
+```sql
+-- With assignment (non-persistent entities, need the result in the flow)
+$PetResponse = IMPORT FROM MAPPING Module.IMM_Pet($JsonContent);
+
+-- Without assignment (persistent entities, just stores to DB)
+IMPORT FROM MAPPING Module.IMM_Pet($JsonContent);
+```
+
+### Export to mapping
+
+Applies an export mapping to an entity object to produce a JSON string:
+
+```sql
+$JsonOutput = EXPORT TO MAPPING Module.EMM_Pet($PetResponse);
+```
+
+### Complete import → process → export microflow
+
+```sql
+CREATE MICROFLOW Module.ProcessPetData ()
+BEGIN
+  DECLARE $ResponseContent String = $latestHttpResponse/Content;
+  $PetResponse = IMPORT FROM MAPPING Module.IMM_Pet($ResponseContent);
+  -- Process the imported data...
+  $JsonOutput = EXPORT TO MAPPING Module.EMM_Pet($PetResponse);
+  LOG INFO NODE 'Integration' 'Exported: ' + $JsonOutput;
+END;
+/
+```
+
+---
+
 ## Complete Example — Bible Verse API
 
 ```sql

cmd/mxcli/help_topics/integration.txt

@@ -13,6 +13,9 @@ SERVICE TYPES
   Published REST:     SHOW PUBLISHED REST SERVICES [IN Module];
   Business Events:    SHOW BUSINESS EVENT SERVICES [IN Module];
   DB Connections:     SHOW DATABASE CONNECTIONS [IN Module];
+  JSON Structures:    SHOW JSON STRUCTURES [IN Module];
+  Import Mappings:    SHOW IMPORT MAPPINGS [IN Module];
+  Export Mappings:    SHOW EXPORT MAPPINGS [IN Module];
   External Entities:  SHOW EXTERNAL ENTITIES [IN Module];
   External Actions:   SHOW EXTERNAL ACTIONS [IN Module];
 

cmd/mxcli/help_topics/rest.txt

@@ -15,6 +15,44 @@ DESCRIBE COMMANDS
   DESCRIBE REST CLIENT MyModule.PetStoreAPI;      -- Full MDL definition
   DESCRIBE PUBLISHED REST SERVICE MyModule.MyAPI; -- Full MDL definition
 
+JSON STRUCTURES & MAPPINGS
+--------------------------
+
+  SHOW JSON STRUCTURES;                             -- List all JSON structures
+  DESCRIBE JSON STRUCTURE Module.JSON_Pet;          -- Element tree + snippet
+  CREATE JSON STRUCTURE Module.JSON_Pet SNIPPET '{"id": 1}';
+
+  SHOW IMPORT MAPPINGS;                             -- List import mappings
+  DESCRIBE IMPORT MAPPING Module.IMM_Pet;           -- Full CREATE statement
+  CREATE IMPORT MAPPING Module.IMM_Pet
+    WITH JSON STRUCTURE Module.JSON_Pet
+  {
+    CREATE Module.PetResponse {
+      PetId = id,
+      Name = name
+    }
+  };
+
+  SHOW EXPORT MAPPINGS;                             -- List export mappings
+  DESCRIBE EXPORT MAPPING Module.EMM_Pet;           -- Full CREATE statement
+  CREATE EXPORT MAPPING Module.EMM_Pet
+    WITH JSON STRUCTURE Module.JSON_Pet
+  {
+    Module.PetResponse {
+      id = PetId,
+      name = Name
+    }
+  };
+
+MICROFLOW ACTIONS
+-----------------
+
+  -- Import from mapping (JSON string → entities)
+  $Pet = IMPORT FROM MAPPING Module.IMM_Pet($JsonContent);
+
+  -- Export to mapping (entity → JSON string)
+  $Json = EXPORT TO MAPPING Module.EMM_Pet($Pet);
+
 CATALOG QUERIES
 ---------------
 

docs-site/src/examples/rest-integration.md

@@ -105,3 +105,77 @@ BEGIN
 END;
 /
 ```
+
+## JSON Structure + Import Mapping
+
+Map a JSON response to Mendix entities using a JSON structure and import mapping.
+
+```sql
+-- Step 1: Define the JSON structure
+CREATE JSON STRUCTURE Integration.JSON_Pet
+  SNIPPET '{"id": 1, "name": "Fido", "status": "available"}';
+
+-- Step 2: Create a non-persistent entity to hold the data
+CREATE NON-PERSISTENT ENTITY Integration.PetResponse (
+  PetId: Integer,
+  Name: String,
+  Status: String
+);
+/
+
+-- Step 3: Create the import mapping
+CREATE IMPORT MAPPING Integration.IMM_Pet
+  WITH JSON STRUCTURE Integration.JSON_Pet
+{
+  CREATE Integration.PetResponse {
+    PetId = id,
+    Name = name,
+    Status = status
+  }
+};
+
+-- Step 4: Use in a microflow with IMPORT FROM MAPPING
+-- $PetResponse = IMPORT FROM MAPPING Integration.IMM_Pet($JsonContent);
+```
+
+## Export Mapping (Entity → JSON)
+
+Serialize entities back to JSON using an export mapping.
+
+```sql
+CREATE EXPORT MAPPING Integration.EMM_Pet
+  WITH JSON STRUCTURE Integration.JSON_Pet
+{
+  Integration.PetResponse {
+    id = PetId,
+    name = Name,
+    status = Status
+  }
+};
+
+-- Use in a microflow with EXPORT TO MAPPING
+-- $JsonOutput = EXPORT TO MAPPING Integration.EMM_Pet($PetResponse);
+```
+
+## Nested Mappings with Associations
+
+Map nested JSON objects to multiple entities linked by associations.
+
+```sql
+CREATE IMPORT MAPPING Integration.IMM_Order
+  WITH JSON STRUCTURE Integration.JSON_Order
+{
+  CREATE Integration.OrderResponse {
+    OrderId = orderId KEY,
+    CREATE Integration.OrderResponse_CustomerInfo/Integration.CustomerInfo = customer {
+      Email = email,
+      Name = name
+    },
+    CREATE Integration.OrderResponse_OrderItem/Integration.OrderItem = items {
+      Sku = sku,
+      Quantity = quantity,
+      Price = price
+    }
+  }
+};
+```

docs/01-project/MDL_FEATURE_MATRIX.md

@@ -199,9 +199,9 @@ Document types that exist in Mendix but have no MDL support:
 | **Web service publish** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | Published SOAP web services |
 | **Web service consume** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | Consumed SOAP web services |
 | **Ext. DB connector** | N | N | N | N | N | N | 05 | N | N | N | N | Y | N | N | N | N | N | External database connections |
-| **Import mappings** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | JSON/XML import mappings |
-| **Export mappings** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | JSON/XML export mappings |
-| **JSON transformations** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | JSON structure definitions |
+| **Import mappings** | Y | Y | Y | N | Y | N | 06 | Y | N | N | P | Y | N | N | N | Y | N | JSON import mappings with v2 syntax |
+| **Export mappings** | Y | Y | Y | N | Y | N | 06 | Y | N | N | P | Y | N | N | N | Y | N | JSON export mappings with v2 syntax |
+| **JSON transformations** | Y | Y | Y | Y | Y | N | 20 | Y | N | N | P | N | N | N | N | N | N | JSON structure definitions |
 | **Message definitions** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | Message definition documents |
 | **XML schemas** | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | Imported XML schema documents |
 | **Workflows** | Y | Y | Y | N | Y | N | N | N | Y | Y | N | N | Y | N | Y | Y | N | SHOW/DESCRIBE/CREATE/DROP/GRANT/REVOKE implemented |

docs/01-project/MDL_QUICK_REFERENCE.md

@@ -172,6 +172,8 @@ AUTHENTICATION Basic, Session
 | WHILE | `WHILE condition BEGIN ... END WHILE;` | Condition-based loop |
 | Return | `RETURN $value;` | Required at end of every flow path |
 | Execute DB query | `$Result = EXECUTE DATABASE QUERY Module.Conn.Query;` | 3-part name; supports DYNAMIC, params, CONNECTION override |
+| Import mapping | `[$Var =] IMPORT FROM MAPPING Module.IMM($SourceVar);` | Apply import mapping to string variable |
+| Export mapping | `$Var = EXPORT TO MAPPING Module.EMM($EntityVar);` | Apply export mapping to entity, returns string |
 | Error handling | `... ON ERROR CONTINUE\|ROLLBACK\|{ handler };` | Not supported on EXECUTE DATABASE QUERY |
 
 ## Microflows - NOT Supported (Will Cause Parse Errors)
@@ -345,6 +347,67 @@ CREATE OR REPLACE NAVIGATION Responsive
 | Create with name map | `CREATE JSON STRUCTURE Module.Name SNIPPET '...' CUSTOM NAME MAP ('jsonKey' AS 'CustomName', ...);` | Override auto-generated ExposedNames |
 | Drop structure | `DROP JSON STRUCTURE Module.Name;` | |
 
+## Import Mappings
+
+| Statement | Syntax | Notes |
+|-----------|--------|-------|
+| Show mappings | `SHOW IMPORT MAPPINGS [IN Module];` | List all or filter by module |
+| Describe mapping | `DESCRIBE IMPORT MAPPING Module.Name;` | Re-executable CREATE statement |
+| Create mapping | See below | Assignment syntax: `Attr = jsonField` |
+| Drop mapping | `DROP IMPORT MAPPING Module.Name;` | |
+
+```sql
+CREATE IMPORT MAPPING Module.IMM_Pet
+  WITH JSON STRUCTURE Module.JSON_Pet
+{
+  CREATE Module.PetResponse {
+    PetId = id KEY,
+    Name = name,
+    Status = status
+  }
+};
+```
+
+**Object handling:** `CREATE` (default), `FIND` (requires KEY), `FIND OR CREATE`
+
+**Nested objects:** Use association path `Assoc/Entity = jsonKey`:
+```sql
+CREATE Module.OrderResponse_CustomerInfo/Module.CustomerInfo = customer {
+  Email = email,
+  Name = name
+}
+```
+
+## Export Mappings
+
+| Statement | Syntax | Notes |
+|-----------|--------|-------|
+| Show mappings | `SHOW EXPORT MAPPINGS [IN Module];` | List all or filter by module |
+| Describe mapping | `DESCRIBE EXPORT MAPPING Module.Name;` | Re-executable CREATE statement |
+| Create mapping | See below | Assignment syntax: `jsonField = Attr` |
+| Drop mapping | `DROP EXPORT MAPPING Module.Name;` | |
+
+```sql
+CREATE EXPORT MAPPING Module.EMM_Pet
+  WITH JSON STRUCTURE Module.JSON_Pet
+  NULL VALUES LeaveOutElement
+{
+  Module.PetResponse {
+    id = PetId,
+    name = Name,
+    status = Status
+  }
+};
+```
+
+**Nested objects:** Use association path `Assoc/Entity AS jsonKey`:
+```sql
+Module.OrderResponse_CustomerInfo/Module.CustomerInfo AS customer {
+  email = Email,
+  name = Name
+}
+```
+
 ## Java Actions
 
 | Statement | Syntax | Notes |

mdl-examples/doctype-tests/06-rest-client-examples.mdl

@@ -1382,7 +1382,67 @@ END;
 /
 
 -- ############################################################################
--- PART 16: VERIFICATION COMMANDS
+-- PART 16: IMPORT/EXPORT MAPPING IN MICROFLOWS
+-- ############################################################################
+
+-- MARK: Import/Export Mapping Actions
+
+-- ============================================================================
+-- Level 16.1: Import from Mapping (with result variable)
+-- ============================================================================
+--
+-- Applies an import mapping to a JSON string to produce entity objects.
+-- The result is stored in a variable for further processing.
+
+CREATE MICROFLOW RestTest.ACT_ImportFromMapping ()
+RETURNS Boolean AS $Success
+BEGIN
+  DECLARE $Success Boolean = false;
+  DECLARE $JsonContent String = '{{\"id\": 1, \"name\": \"Fido\", \"status\": \"available\"}';
+
+  $PetResponse = IMPORT FROM MAPPING RestTest.IMM_Pet($JsonContent);
+
+  IF $PetResponse != empty THEN
+    SET $Success = true;
+    LOG INFO NODE 'RestTest' 'Import succeeded: ' + $PetResponse/Name;
+  END IF;
+
+  RETURN $Success;
+END;
+/
+
+-- ============================================================================
+-- Level 16.2: Export to Mapping (entity to JSON string)
+-- ============================================================================
+--
+-- Applies an export mapping to an entity object to produce a JSON string.
+
+CREATE MICROFLOW RestTest.ACT_ExportToMapping ($PetResponse: RestTest.PetResponse)
+RETURNS String AS $JsonOutput
+BEGIN
+  $JsonOutput = EXPORT TO MAPPING RestTest.EMM_Pet($PetResponse);
+  LOG INFO NODE 'RestTest' 'Exported JSON: ' + $JsonOutput;
+  RETURN $JsonOutput;
+END;
+/
+
+-- ============================================================================
+-- Level 16.3: Import → Process → Export pipeline
+-- ============================================================================
+--
+-- Full pipeline: receive JSON, import to entities, process, export back to JSON.
+
+CREATE MICROFLOW RestTest.ACT_ImportProcessExport ()
+BEGIN
+  DECLARE $JsonContent String = '{{\"id\": 1, \"name\": \"Fido\", \"status\": \"available\"}';
+  $PetResponse = IMPORT FROM MAPPING RestTest.IMM_Pet($JsonContent);
+  $PetResponseJson = EXPORT TO MAPPING RestTest.EMM_Pet($PetResponse);
+  LOG INFO NODE 'RestTest' 'Round-tripped: ' + $PetResponseJson;
+END;
+/
+
+-- ############################################################################
+-- PART 17: VERIFICATION COMMANDS
 -- ############################################################################
 
 -- MARK: Verification

mdl/ast/ast_microflow.go

@@ -623,3 +623,25 @@ type SendRestRequestStmt struct {
 }
 
 func (s *SendRestRequestStmt) isMicroflowStatement() {}
+
+// ImportFromMappingStmt represents: [$Var =] IMPORT FROM MAPPING Module.IMM($SourceVar)
+type ImportFromMappingStmt struct {
+	OutputVariable string               // Optional result variable (without $)
+	Mapping        QualifiedName        // Import mapping qualified name
+	SourceVariable string               // Input string variable (without $)
+	ErrorHandling  *ErrorHandlingClause // Optional ON ERROR clause
+	Annotations    *ActivityAnnotations // Optional @position, @caption, @color, @annotation
+}
+
+func (s *ImportFromMappingStmt) isMicroflowStatement() {}
+
+// ExportToMappingStmt represents: $Var = EXPORT TO MAPPING Module.EMM($SourceVar)
+type ExportToMappingStmt struct {
+	OutputVariable string               // Result string variable (without $)
+	Mapping        QualifiedName        // Export mapping qualified name
+	SourceVariable string               // Input entity variable (without $)
+	ErrorHandling  *ErrorHandlingClause // Optional ON ERROR clause
+	Annotations    *ActivityAnnotations // Optional @position, @caption, @color, @annotation
+}
+
+func (s *ExportToMappingStmt) isMicroflowStatement() {}