Module eval 

Formula evaluation engine.

Evaluates parsed formula ASTs against cell data provided through the CellDataProvider trait. Supports arithmetic, comparison, string concatenation, cell/range references, and built-in function calls.

Structs

CellCoord

A cell coordinate used as a node in the dependency graph.

CellSnapshot

In-memory snapshot of cell data, decoupled from any Workbook borrow.

Evaluator

Stateful evaluator that tracks recursion depth and circular references.

Traits

CellDataProvider

Provides cell data for formula evaluation.

Functions

build_dependency_graph

Build a dependency graph from formula cells. Returns a map from each formula cell to the cells it depends on.

coerce_to_bool

Coerce a CellValue to a boolean. Numbers: 0 is false, nonzero is true. Strings “TRUE”/“FALSE” are recognized. Empty is false.

coerce_to_number

Coerce a CellValue to f64. Booleans become 0/1, empty becomes 0, numeric strings are parsed. Non-numeric strings yield an error.

coerce_to_string

Coerce a CellValue to a string.

compare_values

Compare two CellValues for ordering. Uses Excel comparison semantics: numbers compare numerically, strings compare case-insensitively, mixed types rank as: empty < number < string < bool.

evaluate

Evaluate a parsed formula expression against the given cell data provider.

topological_sort

Topological sort of formula cells based on dependencies. Returns cells in evaluation order (dependencies first). Detects cycles and returns an error if found.