Sorted

[maxatome]

usage:

Sorted([HOW_TO_SORT])

Sorted would be an operator allowing to check whether a slice or an array is sorted or not.

Accepted input: any slice or array.

If the input is []T or [n]T, HOW_TO_SORT is optional, it defaults to 1, and can be:

• 1 or any int > 0: checks the slice/array is ordered in ascending order;
• -1 or any int < 0: checks the slice/array is ordered in descending order;
• func (a, b T) bool returning true if a < b: checks the slice/array is ordered according to the function passed;
• []string{"FIELD1", "FIELD2", …}: only if T is a struct or a pointer on a struct, checks the slice/array of structs is ordered by struct field FIELD1, then by field FIELD2, …
  Fields can be prefixed by "-" to specify a descending order instead of ascending default one.

Default sorting would be handled the same way tdutil.SortableValues does.

Examples of use:

got := []int{-3, -1, 0, 2, 4}

// This one succeeds
td.Cmp(t, got, td.Sorted())

// As this one
td.Cmp(t, got, td.Sorted(1))

// But not this one
td.Cmp(t, got, td.Sorted(-1))

// Success using a function
td.Cmp(t, got, td.Sorted(func (a, b int) bool { return a < b }))

// Slice of structs
type Person struct {
  Name      string
  FirstName string
  Age       int
}
got := []Person{
  {Name: "Doe", FirstName: "John", Age: 18},
  {Name: "Smith", FirstName: "Bob", Age: 20},
  {Name: "Smith", FirstName: "Alice", Age: 18},
}

// The following fails, as by default struct ordering is done field/field
td.Cmp(t, got, td.Sorted())

// This one succeeds: order by Name ASC then by Age DESC
td.Cmp(t, got, td.Sorted([]string{"Name", "-Age"}))

[maxatome]

Implemented in branch sort, doc & tests to be completed, examples to be done.