mcuadros / go-lookup

Small library on top of reflect for make lookups to any Structs or Maps

go-lookup

Small library on top of reflect for make lookups to Structs or Maps. Using a very simple DSL you can access to any property, key or value of any value of Go.

Installation

The recommended way to install go-lookup

go get github.com/mcuadros/go-lookup

Example

type Cast struct {
  Actor, Role string
}

type Serie struct {
  Cast []Cast
}

series := map[string]Serie{
  "A-Team": {Cast: []Cast{
    {Actor: "George Peppard", Role: "Hannibal"},
    {Actor: "Dwight Schultz", Role: "Murdock"},
    {Actor: "Mr. T", Role: "Baracus"},
    {Actor: "Dirk Benedict", Role: "Faceman"},
  }},
}

q := "A-Team.Cast.Role"
value, _ := LookupString(series, q)
fmt.Println(q, "->", value.Interface())
// A-Team.Cast.Role -> [Hannibal Murdock Baracus Faceman]

q = "A-Team.Cast[0].Actor"
value, _ = LookupString(series, q)
fmt.Println(q, "->", value.Interface())
// A-Team.Cast[0].Actor -> George Peppard

Case-insensitive matching

Use the LookupI and LookupStringI functions to do a case-insensitive match on struct field names and map keys. It will first look for an exact match; if that fails, it will fall back to a more expensive linear search over fields/keys.

type ExampleStruct struct {
  SoftwareUpdated bool
}

i := ExampleStruct{
  SoftwareUpdated: true,
}

value, _ := LookupStringI(i, "softwareupdated")
fmt.Println(value.Interface())
// Output: true

License

MIT, see LICENSE

go-lookup's Issues

Lookup slice index of map field?

I was expecting this to work but it does not. I'm using commit 5415b5b

func TestLookupMapSliceIndex(t *testing.T) {
	assert := assert.New(t)
	m := map[string]any{
		"test-name": []string{"test-value"},
	}

	v, e := lookup.LookupString(m, "test-name[0]")
	assert.NoError(e)
	assert.Equal("test-value", v.String())
}