//! The calculator core: errors, evaluation, expression preprocessing, number
//! formatting, variables and history. This layer is pure (no I/O) and holds the
//! single source of truth for how calcli computes and renders values.
pubmoderror;pubmodevaluator;pubmodexpression;pubmodformat;pubmodhighlight;pubmodhistory;pubmodquantity;pubmodunits;pubmodvariables;