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| |
| _Types ~~and~~ are Values_ |
| |
| # Bottom |
| |
| Specifying duplicate fields with conflicting values results in an error |
| or bottom. |
| _Bottom_ is a special value in CUE, denoted `_|_`, that indicates an |
| error such as conflicting values. |
| Any error in CUE results in `_|_`. |
| Logically all errors are equal, although errors may be associated with |
| metadata such as an error message. |
| |
| Note that an error is different from `null`: `null` is a valid value, |
| whereas `_|_` is not. |
| |
| <!-- CUE editor --> |
| _bottom.cue:_ |
| ``` |
| a: 4 |
| a: 5 |
| |
| l: [ 1, 2 ] |
| l: [ 1, 3 ] |
| |
| list: [0, 1, 2] |
| val: list[3] |
| ``` |
| |
| <!-- result --> |
| `$ cue eval -i bottom.cue` |
| ``` |
| list: [0, 1, 2] |
| a: _|_ /* conflicting values 4 and 5 */ |
| l: [1, _|_ /* conflicting values 2 and 3 */] |
| val: _|_ /* index 3 out of bounds */ |
| ``` |
