pub fn convert(val: f64, from: &str, to: &str) -> Result<f64, UnitError>Expand description
Convert a value from one unit to another.
Both units must belong to the same quantity (e.g. both are lengths).
Units can be specified by name ("fahrenheit") or symbol ("°F").
§Precision
Conversions use IEEE 754 double-precision arithmetic. Chained conversions (e.g., °F → °C → K → °F) may accumulate floating-point error on the order of ±1e-10. For exact round-trip fidelity, convert directly between source and target units rather than through intermediaries.