This Commented CUE demonstrates how to use the built-in function list.IsSortedStrings as a field validator to assert that lists of strings are sorted alphabetically.

package example

import "list"

sorted: ["A", "B", "C"]
unsorted: ["B", "C", "A"]

sorted:   list.IsSortedStrings
unsorted: list.IsSortedStrings // validation failure

$ cue eval
unsorted: invalid value ["B","C","A"] (does not satisfy list.IsSortedStrings):
    ./file.cue:6:11
    ./file.cue:9:11

Related content

• How-to Guide: Using "list.IsSortedStrings" to report if lists of strings are sorted
• How-to Guide: Using "list.IsSorted" as a field validator
• The list built-in package