Mapping between a source object and a destination or target object uses techniques and functoids that provide an auto-linking feature in which mappings are automatically provided based solely on source and target field names, or, ignoring field names, field locations within hierarchy. Functoids provide support for callout to programming artifacts, such as custom programming logic embedded in .NET assemblies or custom XSLT, and table-looping to generate and map data into a target document even though that data did not exist in the map input.