Removes unused methods (sum_matching, get_mut, item_by_name, item_index,
top_level_groups, is_group_collapsed, show_item) and unused constants
(LABEL_THRESHOLD, MIN_COL_WIDTH).
The sum_matching tests in model.rs were bypassing the formula evaluator
entirely. Replaced them with equivalent tests that call evaluate() against
the existing Total = SUM(Revenue) formula, exercising the real aggregation
code path.
Also fixes a compile error in view.rs prop_tests where View/Axis imports
and a doc comment were incorrectly commented out.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The CSV export used Box<dyn Iterator<Item = Option<usize>>> to unify
empty and non-empty row iteration, violating the CLAUDE.md rule that
Box/Rc container management should be split from logic. Replaced with a
direct for loop over row indices, removing both the Box and the Option
sentinels used to represent "placeholder empty row/col".
Also removes unused pub use cell::CellKey re-export and an unused
import in cell.rs tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Previously CellValue had three variants: Number, Text, and Empty.
The Empty variant acted as a null sentinel, but the compiler could not
distinguish between "this is a real value" and "this might be empty".
Code that received a CellValue could use it without checking for Empty,
because there was no type-level enforcement.
Now CellValue has only Number and Text. The absence of a value is
represented as None at every API boundary:
DataStore::get() → Option<&CellValue> (was &CellValue / Empty)
Model::get_cell() → Option<&CellValue> (was &CellValue / Empty)
Model::evaluate() → Option<CellValue> (was CellValue::Empty)
eval_formula() → Option<CellValue> (was CellValue::Empty)
Model gains clear_cell() for explicit key removal; ClearCell dispatch
calls it instead of set_cell(key, CellValue::Empty).
The compiler now forces every caller of evaluate/get_cell to handle
the None case explicitly — accidental use of an empty value as if it
were real is caught at compile time rather than silently computing
wrong results.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
