4 files changed, 184 insertions, 0 deletions
diff --git a/data/data.go b/data/data.go
index adf6b2b7..d2fc32fb 100644
--- a/data/data.go
+++ b/data/data.go
@@ -12,6 +12,9 @@ import (
 	"io"
 	"strings"
 
+	"cuelang.org/go/cue"
+	"cuelang.org/go/cue/cuecontext"
+	"cuelang.org/go/cue/format"
 	"github.com/Shopify/ejson"
 	ejsonJson "github.com/Shopify/ejson/json"
 	"github.com/hairyhenderson/gomplate/v4/conv"
@@ -442,3 +445,63 @@ func ToTOML(in interface{}) (string, error) {
 	}
 	return buf.String(), nil
 }
+
+// CUE - Unmarshal a CUE expression into the appropriate type
+func CUE(in string) (interface{}, error) {
+	cuectx := cuecontext.New()
+	val := cuectx.CompileString(in)
+
+	if val.Err() != nil {
+		return nil, fmt.Errorf("unable to process CUE: %w", val.Err())
+	}
+
+	switch val.Kind() {
+	case cue.StructKind:
+		out := map[string]interface{}{}
+		err := val.Decode(&out)
+		return out, err
+	case cue.ListKind:
+		out := []interface{}{}
+		err := val.Decode(&out)
+		return out, err
+	case cue.BytesKind:
+		out := []byte{}
+		err := val.Decode(&out)
+		return out, err
+	case cue.StringKind:
+		out := ""
+		err := val.Decode(&out)
+		return out, err
+	case cue.IntKind:
+		out := 0
+		err := val.Decode(&out)
+		return out, err
+	case cue.NumberKind, cue.FloatKind:
+		out := 0.0
+		err := val.Decode(&out)
+		return out, err
+	case cue.BoolKind:
+		out := false
+		err := val.Decode(&out)
+		return out, err
+	case cue.NullKind:
+		return nil, nil
+	default:
+		return nil, fmt.Errorf("unsupported CUE type %q", val.Kind())
+	}
+}
+
+func ToCUE(in interface{}) (string, error) {
+	cuectx := cuecontext.New()
+	v := cuectx.Encode(in)
+	if v.Err() != nil {
+		return "", v.Err()
+	}
+
+	bs, err := format.Node(v.Syntax())
+	if err != nil {
+		return "", err
+	}
+
+	return string(bs), nil
+}
diff --git a/data/data_test.go b/data/data_test.go
index 2ea6365e..324a3600 100644
--- a/data/data_test.go
+++ b/data/data_test.go
@@ -660,3 +660,120 @@ func TestStringifyYAMLMapMapKeys(t *testing.T) {
 		assert.EqualValues(t, c.want, c.input)
 	}
 }
+
+func TestCUE(t *testing.T) {
+	in := `package foo
+import "regexp"
+matches: regexp.FindSubmatch(#"^([^:]*):(\d+)$"#, "localhost:443")
+one: 1
+two: 2
+// A field using quotes.
+"two-and-a-half": 2.5
+list: [ 1, 2, 3 ]
+`
+
+	expected := map[string]interface{}{
+		"matches": []interface{}{
+			"localhost:443",
+			"localhost",
+			"443",
+		},
+		"one":            1,
+		"two":            2,
+		"two-and-a-half": 2.5,
+		"list":           []interface{}{1, 2, 3},
+	}
+
+	out, err := CUE(in)
+	require.NoError(t, err)
+	assert.EqualValues(t, expected, out)
+
+	out, err = CUE(`[1,2,3]`)
+	require.NoError(t, err)
+	assert.EqualValues(t, []interface{}{1, 2, 3}, out)
+
+	out, err = CUE(`"hello world"`)
+	require.NoError(t, err)
+	assert.EqualValues(t, "hello world", out)
+
+	out, err = CUE(`true`)
+	require.NoError(t, err)
+	assert.EqualValues(t, true, out)
+
+	out, err = CUE(`'\x00\x01\x02\x03\x04'`)
+	require.NoError(t, err)
+	assert.EqualValues(t, []byte{0, 1, 2, 3, 4}, out)
+
+	out, err = CUE(`42`)
+	require.NoError(t, err)
+	assert.EqualValues(t, 42, out)
+
+	out, err = CUE(`42.0`)
+	require.NoError(t, err)
+	assert.EqualValues(t, 42.0, out)
+
+	out, err = CUE(`null`)
+	require.NoError(t, err)
+	assert.EqualValues(t, nil, out)
+
+	_, err = CUE(`>=0 & <=7 & >=3 & <=10`)
+	require.Error(t, err)
+}
+
+func TestToCUE(t *testing.T) {
+	in := map[string]interface{}{
+		"matches": []interface{}{
+			"localhost:443",
+			"localhost",
+			"443",
+		},
+		"one":            1,
+		"two":            2,
+		"two-and-a-half": 2.5,
+		"list":           []interface{}{1, 2, 3},
+	}
+
+	expected := `{
+	"two-and-a-half": 2.5
+	list: [1, 2, 3]
+	two: 2
+	one: 1
+	matches: ["localhost:443", "localhost", "443"]
+}`
+
+	out, err := ToCUE(in)
+	require.NoError(t, err)
+	assert.EqualValues(t, expected, out)
+
+	out, err = ToCUE([]interface{}{1, 2, 3})
+	require.NoError(t, err)
+	assert.EqualValues(t, `[1, 2, 3]`, out)
+
+	out, err = ToCUE("hello world")
+	require.NoError(t, err)
+	assert.EqualValues(t, `"hello world"`, out)
+
+	out, err = ToCUE(true)
+	require.NoError(t, err)
+	assert.EqualValues(t, `true`, out)
+
+	out, err = ToCUE([]byte{0, 1, 2, 3, 4})
+	require.NoError(t, err)
+	assert.EqualValues(t, `'\x00\x01\x02\x03\x04'`, out)
+
+	out, err = ToCUE(42)
+	require.NoError(t, err)
+	assert.EqualValues(t, `42`, out)
+
+	out, err = ToCUE(42.0)
+	require.NoError(t, err)
+	assert.EqualValues(t, `42.0`, out)
+
+	out, err = ToCUE(nil)
+	require.NoError(t, err)
+	assert.EqualValues(t, `null`, out)
+
+	out, err = ToCUE(struct{}{})
+	require.NoError(t, err)
+	assert.EqualValues(t, `{}`, out)
+}
diff --git a/data/datasource.go b/data/datasource.go
index d16fe09a..fe3f0877 100644
--- a/data/datasource.go
+++ b/data/datasource.go
@@ -32,6 +32,7 @@ func init() {
 	regExtension(".csv", csvMimetype)
 	regExtension(".toml", tomlMimetype)
 	regExtension(".env", envMimetype)
+	regExtension(".cue", cueMimetype)
 }
 
 // registerReaders registers the source-reader functions
@@ -348,6 +349,8 @@ func parseData(mimeType, s string) (out interface{}, err error) {
 		out, err = dotEnv(s)
 	case textMimetype:
 		out = s
+	case cueMimetype:
+		out, err = CUE(s)
 	default:
 		return nil, fmt.Errorf("datasources of type %s not yet supported", mimeType)
 	}
diff --git a/data/mimetypes.go b/data/mimetypes.go
index bdc12ad4..1f243219 100644
--- a/data/mimetypes.go
+++ b/data/mimetypes.go
@@ -8,6 +8,7 @@ const (
 	tomlMimetype      = "application/toml"
 	yamlMimetype      = "application/yaml"
 	envMimetype       = "application/x-env"
+	cueMimetype       = "application/cue"
 )
 
 // mimeTypeAliases defines a mapping for non-canonical mime types that are