# `SpdxLicence`

A software licence as SPDX writes it: `MIT OR Apache-2.0`.

Use it for a package's licence.

## Shape

One value, held as text in one set form, with no parts: `DocumentRef-spdx-tool-1.2:LicenseRef-MIT-Style-2`.

## Example

```jadpo
SpdxLicence("MIT OR Apache-2.0")
```

`SpdxLicence(raw)` checks the text, and text that isn't one breaks the `format` rule.

`text.parse(raw, as: SpdxLicence)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as `mit`, `Apache-2` or `MIT or Apache-2.0`.

## Good to know

- Each name is spelled as the SPDX list has it, so `mit` and `Apache-2` are refused.
- `==` tells you whether two are the same. `<` and `list.sort_by` don't take it.

## In JSON

A string, in a request, a response or `json.write`:

```json
"MIT"
"Apache-2.0"
"MIT OR Apache-2.0"
```

## Details

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

`SpdxLicence` is in the group Software, 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: `MIT`, `Apache-2.0` and `MIT OR Apache-2.0`.

### How it is stored

It is stored in one column named for the field, of type `text`. `(MIT OR Apache-2.0) AND BSD-3-Clause` is stored as `'(MIT OR Apache-2.0) AND BSD-3-Clause'`.

### How it is shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `MIT` | `MIT` |
| `Apache-2.0` | `Apache-2.0` |
| `MIT OR Apache-2.0` | `MIT OR Apache-2.0` |
| `GPL-2.0-or-later WITH Classpath-exception-2.0` | `GPL-2.0-or-later WITH Classpath-exception-2.0` |
| `(MIT OR Apache-2.0) AND BSD-3-Clause` | `(MIT OR Apache-2.0) AND BSD-3-Clause` |
| `LGPL-2.1+` | `LGPL-2.1+` |
| `LicenseRef-acme-internal` | `LicenseRef-acme-internal` |
| `DocumentRef-spdx-tool-1.2:LicenseRef-MIT-Style-2` | `DocumentRef-spdx-tool-1.2:LicenseRef-MIT-Style-2` |

### Operations

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>