| cue eval -i structs.cue |
| cmp stdout expect-stdout-cue |
| |
| -- frontmatter.toml -- |
| title = "Closed structs" |
| description = "" |
| |
| -- text.md -- |
| Struct is the most important composite type in CUE. |
| |
| A struct may be open or closed. |
| A closed struct may only be merged with structs that have fields that |
| it defines to be allowed. |
| In other words, closing a struct is equivalent to requiring that all |
| other values be undefined. |
| |
| A closed struct can be created using the `close` builtin, |
| but are more commonly defined using a _definition_, defined next. |
| |
| -- structs.cue -- |
| a: close({ |
| field: int |
| }) |
| |
| b: a & { |
| feild: 3 |
| } |
| |
| -- expect-stdout-cue -- |
| a: { |
| field: int |
| } |
| b: _|_ // field "feild" not allowed in closed struct |
