This test validates that the STEPcode-generated C++ code from both AP242 schemas can correctly handle styled_item entities, particularly the WHERE rule WR3 that was problematic in the original schema.

Two tests are provided:

1. Vanilla AP242 (ap242_vanilla_styled_item) - Uses flow-sensitive type narrowing (STEPcode extension)
2. AP242 TREAT (ap242_styled_item) - Uses explicit TREAT expression (ISO 10303-11 compliant)

The AP242 schema contains a styled_item entity with a complex WHERE rule (WR3) that requires type narrowing from a SELECT type to an aggregate type:

ENTITY styled_item
  SUBTYPE OF (representation_item);
  styles : SET [0 : ?] OF presentation_style_assignment;
  item   : styled_item_target;
WHERE
  WR3: ('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF.MAPPED_ITEM' IN TYPEOF(item)) OR
       ('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF.GEOMETRIC_REPRESENTATION_ITEM' IN TYPEOF(item)) OR
       (('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF.SET_REPRESENTATION_ITEM' IN TYPEOF(item)) AND
        (SIZEOF(QUERY(it
                      <* TREAT(item AS set_representation_item)  -- TREAT in ap242treat
                      <* item                                     -- flow-sensitive in vanilla ap242
                      | NOT (('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF.MAPPED_ITEM' IN TYPEOF(it)) OR
                             ('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF.GEOMETRIC_REPRESENTATION_ITEM' IN
                              TYPEOF(it))))) =
         0));
END_ENTITY;

Uses flow-sensitive type narrowing - STEPcode recognizes the TYPEOF guard pattern and automatically narrows the type:

QUERY(it <* item | ...)  -- item is implicitly narrowed to set_representation_item

Uses explicit TREAT expression - ISO 10303-11 compliant approach:

QUERY(it <* TREAT(item AS set_representation_item) | ...)  -- explicit type narrowing

Both approaches produce identical, correct output.

• test_ap242_styled_item.stp - Minimal AP242 STEP file containing styled_item instances (used by both tests)
• test/cpp/schema_specific/ap242_vanilla_styled_item.cc - C++ test for vanilla AP242 (flow-sensitive narrowing)
• test/cpp/schema_specific/ap242_styled_item.cc - C++ test for AP242 TREAT (explicit TREAT expression)

Both tests:

1. Read the same AP242 STEP file containing styled_item entities
2. Parse it using their respective generated libraries (libsdai_242_mim_lf.so or libsdai_ap242treat.so)
3. Verify that styled_item instances are correctly parsed and accessible
4. Validate the entity relationships and attributes

The key difference is which schema/library is used, demonstrating that both approaches handle the same data correctly.

# Build both AP242 schemas and tests
cd build
ninja sdai_242_mim_lf      # vanilla AP242 schema
ninja sdai_ap242treat      # TREAT AP242 schema
ninja tst_ap242_vanilla_styled_item
ninja tst_ap242_styled_item

# Run the vanilla AP242 test (flow-sensitive narrowing)
./bin/tst_ap242_vanilla_styled_item ../test/p21/test_ap242_styled_item.stp

# Run the TREAT AP242 test (explicit TREAT)
./bin/tst_ap242_styled_item ../test/p21/test_ap242_styled_item.stp

Or via CTest:

ctest -R ap242.*styled_item -V

For both tests:

• The STEP file parses without errors
• styled_item entities are found and accessible
• The generated C++ code correctly handles the WR3 WHERE rule (with flow-sensitive narrowing or TREAT)
• No crashes or segmentation faults occur

• data/ap242/242_mim_lf.exp - Vanilla AP242 schema (flow-sensitive narrowing)
• data/ap242treat/README.md - AP242 TREAT schema documentation
• doc/ap242-comparison.md - Comparison of flow-sensitive narrowing vs TREAT
• Problem statement: ENTITY styled_item with type narrowing support