rounding

Rounding modes for decimal arithmetic.

Every operation in finanza/decimal that can reduce precision takes a Mode so the rounding behaviour is explicit. The seven modes match the IBM General Decimal Arithmetic specification (see doc/reference/specs/ibm-decimal-arithmetic.md).

Types

Mode

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The rounding mode applied when a decimal operation must drop digits.

HalfEven is the canonical financial default (“banker’s rounding”): it rounds half-way values to the nearest even digit, which avoids the systematic upward bias of HalfUp when many roundings are summed.

pub type Mode {
  HalfEven
  HalfUp
  HalfDown
  Up
  Down
  Ceiling
  Floor
}

Constructors

```
HalfEven
```
Round half-way values to the nearest even digit. 2.5 -> 2, 3.5 -> 4, -2.5 -> -2.
```
HalfUp
```
Round half-way values away from zero. 2.5 -> 3, -2.5 -> -3.
```
HalfDown
```
Round half-way values toward zero. 2.5 -> 2, -2.5 -> -2.
```
Up
```
Always round away from zero. 2.1 -> 3, -2.1 -> -3.
```
Down
```
Always round toward zero (truncate). 2.9 -> 2, -2.9 -> -2.
```
Ceiling
```
Always round toward +∞. 2.1 -> 3, -2.9 -> -2.
```
Floor
```
Always round toward -∞. 2.9 -> 2, -2.1 -> -3.