# `BloodGlucose`

A blood sugar level, shown `5.5 mmol/L`.

Use it for a person's reading. For any other concentration, use [`Concentration`](/docs/types/type-concentration.md).

## Shape

One `Concentration`, with limits of its own.

## Example

```jadpo
BloodGlucose(0.99gL)
```

A value outside its limits breaks `min` or `max`.

`text.parse(raw, as: BloodGlucose)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as `5.5`, `mmol/L` or `high`.

These operations give one: `units.of` and `units.sum`.

## Good to know

- It is shown in millimoles per litre, so `0.99gL` shows as `5.5 mmol/L`. To start from that figure, use `units.of(5.5, ConcentrationUnit.millimole_of_glucose_per_litre)`.
- It can't be below zero.
- `==` tells you whether two are the same, and `<` and `list.sort_by` compare and sort them.
- A field that holds one counts as personal data (`health`), so you don't mark it yourself.

## In JSON

An object of its parts, in a request, a response or `json.write`:

```json
{"value":"0.7206228","unit":"gL"}
{"value":"0.99","unit":"gL"}
{"value":"0.99085635","unit":"gL"}
```

## Details

<details>
<summary>Text form, storage, how it is shown, and operations</summary>

`BloodGlucose` is in the group Health, and has been in Jadpo since 0.1.0.

### Text form

`text.from` writes one standard text form, the same form `text.parse` reads back: `0.7206228 gL`, `0.99 gL` and `0.99085635 gL`.

### How it is stored

It is stored in one column named for the field, of type `numeric(38, 9)`, holding the concentration in grams per litre (g/L). `0.99085635 gL` is stored as `0.99085635`.

### How it is shown to people

`text.format(value, locale:)` shows it to people in their locale. A call may also give `unit:`.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `0.7206228 gL` | `4 mmol/L` |
| `0.99 gL` | `5.5 mmol/L` |
| `0.99085635 gL` | `5.5 mmol/L` |
| `2.01774384 gL` | `11.2 mmol/L` |

### Operations

- `units.in(value: Quantity, unit: QuantityUnit, scale: Int, rounding: Rounding) -> Decimal`: `value` in `unit`, a unit of its kind, as a `Decimal` of `scale` places rounded by `rounding`: `units.in(5km, LengthUnit.mile, scale: 2, rounding: Rounding.half_even)` is `3.11`.
- `units.of(value: Number, unit: QuantityUnit) -> Quantity`: `value` of `unit`, an `Int` or a `Decimal`, as the quantity of `unit`'s kind, converted exactly to the base unit and rounded half to even to the kind's scale: `units.of(5, LengthUnit.mile)`.
- `units.sum(items: List<Quantity>) -> Quantity`: The items added up, all of one kind; nothing for no items. A `Temperature` or a `SoundLevel` doesn't add to itself, so neither is summed.

It also takes `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. [How every standard type behaves](/docs/every-standard-type-meets-one-contract.md) says how they work.

</details>