Files
ConformalLabpp/code/include
Tarik Moussa 039cc26e36
Some checks failed
C++ Tests / test-fast (push) Successful in 1m58s
C++ Tests / test-fast (pull_request) Successful in 2m33s
API Docs / doc-build (pull_request) Successful in 51s
C++ Tests / test-cgal (push) Has been skipped
C++ Tests / test-cgal (pull_request) Failing after 10m32s
Phase 8b-Lite: pipe-operator chaining for named parameters
Adds `operator|` in `namespace CGAL` so package-local named parameters
can be combined left-to-right without modifying CGAL upstream:

    auto p = CGAL::parameters::gradient_tolerance(1e-12)
           | CGAL::parameters::max_iterations(500)
           | CGAL::parameters::output_uv_map(uv);
    CGAL::discrete_conformal_map_euclidean(mesh, p);

Why not the canonical `.a().b().c()` syntax
───────────────────────────────────────────
CGAL's standard chaining mechanism requires registering each named
parameter as a member function on `Named_function_parameters` via the
`CGAL_add_named_parameter` macro in
`CGAL/STL_Extension/internal/parameters_interface.h` — a vendored
upstream file that conformallab++ deliberately treats as read-only.

Adding member-function chainers for our package-local tags would
require either forking CGAL or modifying the vendored copy.  Neither
is acceptable for a library that wants to remain portable across
future CGAL releases.

The pipe-operator achieves the same compositional semantics via a
free function in `namespace CGAL` (so ADL finds it for
`Named_function_parameters` operands).  Implementation: rebuild the
right-hand-side `Named_function_parameters` with the left-hand-side
as its `Base`, producing an indistinguishable chain that every entry
function accepts unchanged.

Implementation: `code/include/CGAL/Conformal_map/internal/parameters.h`
lines 158-187.  The operator is constrained to right-hand-sides with
`No_property` base (i.e. fresh single-parameter packs from the helper
functions), so it never collides with any future CGAL operator on the
same type.

Tests (2 new, total Phase-8b-Lite suite 15 → 17)
────────────────────────────────────────────────
* CGALPhase8bLite.NamedParamPipe_MultipleParamsTakeEffect
    Chain three parameters; verify all three take effect (tight
    tolerance respected + UV pmap populated + iteration cap honoured).
* CGALPhase8bLite.NamedParamPipe_TwoParams
    Chain two parameters; verify max_iterations(0) blocks the loop
    even when combined with another param.

Full CGAL suite: 234/234 PASSED, 0 SKIPPED (was 232).
Total: 257/257 PASSED, 0 SKIPPED (was 255).
scripts/check-test-counts.sh: OK.

Documentation updates
─────────────────────
* doc/tutorials/add-output-uv-map.md §3.4: "Current limitation: no
  chaining" → "Chaining: use the pipe operator `|`".  Explains why
  CGAL's `.member()` syntax isn't available and shows the `|`
  workaround with a working code example.
* doc/architecture/locked-vs-flexible.md §8: chaining now flagged as
  shipped via pipe; recommended posture says `.member()` chaining
  only if a user pushes for the CGAL-canonical syntax.
* doc/roadmap/porting-status.md §5: API limitations table updated.
* doc/api/tests.md: CGALPhase8bLite row 15 → 17, total 232 → 234.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-22 13:43:52 +02:00
..