ABAP 7.50 – CORRESPONDING

But as you all know there is a prominent exception to that rule: All the syntax forms involving CORRESPONDING for assigning structure components that (by chance) have the same name.
  • Before ABAP 7.40, these were mainly MOVE-CORRESPONDING for the components of structures, the CORRESPONDING addition to Open SQL’s SELECT, and some obsolete calculation statements.
  • With ABAP 7.40 MOVE-CORRESPONDING was enabled to handle structured internal tables and a new constructor operator CORRESPONDING was introduced that allows an explicit mapping of structure components with different names.
What was still missing?  A dynamic mapping capability! And this was introduced with ABAP 7.50.
The new system class CL_ABAP_CORRESPONDING allows you to assign components of structures or internal tables with dynamically specified mapping rules.
The mapping rules are created in a mapping table that is passed to a mapping object, e.g. as follows:
DATA(mapper) =
  cl_abap_corresponding=>create(
    source      = struct1
    destination = struct2
    mapping     = VALUE cl_abap_corresponding=>mapping_table(
     ( level   = 0
       kind    = cl_abap_corresponding=>mapping_component
       srcname = ‘…’
       dstname = ‘…’ )
     ( level   = 0
       kind    = cl_abap_corresponding=>mapping_component
       srcname = ‘…’
       dstname = ‘…’ )
     ( level   = 0
       kind    = cl_abap_corresponding=>mapping_component
       srcname = ‘…’
       dstname = ‘…’ ) ) ).
This is a simple example, where all structure components are on top level (0) and where all components are to be mapped (kind = cl_abap_coresponding=>mapping_component). More complicated forms involve nested structures and exclusions. With srcname and dstname the component names  can be specified dynamically. The table setup is similar to the mapping-clause of the CORRESPONDING operator.
After creating the mapping object, all you have to do is to execute the assignment as follows:
mapper->execute( EXPORTING source      = struct1
                 CHANGING  destination = struct2 ).
You can do that again and again for all structures or internal tables that have the same types as those used for creating the mapping object.

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