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| _Expressions_ | |
| # Null Coalescing | |
| With null coalescing we really mean error, or bottom, coalescing. | |
| The defaults mechanism for disjunctions can also be | |
| used to provide fallback values in case an expression evaluates to bottom. | |
| In the example the fallback values are specified | |
| for `a` and `b` in case the list index is out of bounds. | |
| <!-- CUE editor --> | |
| ``` | |
| list: [ "Cat", "Mouse", "Dog" ] | |
| a: list[0] | "None" | |
| b: list[5] | "None" | |
| ``` | |
| <!-- result --> | |
| ``` | |
| list: [ "Cat", "Mouse", "Dog" ] | |
| a: "Cat" | |
| b: "None" | |
| ``` |