cue/encoding: add package
Change-Id: I9307816b073eca99ea7cf94631866d2f1f5d2782
diff --git a/cue/encoding/encoding.go b/cue/encoding/encoding.go
new file mode 100644
index 0000000..c5f2ca6
--- /dev/null
+++ b/cue/encoding/encoding.go
@@ -0,0 +1,54 @@
+// Copyright 2018 The CUE Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package encoding provides support for managing data format files supported
+// by CUE.
+package encoding // import "cuelang.org/go/cue/encoding"
+
+import "strings"
+
+// Encoding represents a data encoding.
+type Encoding struct {
+ name string
+}
+
+// Name returns a lowercase name of an encoding. This is conventionally the most
+// common file extension in lower case.
+func (e *Encoding) Name() string {
+ return e.name
+}
+
+// All returns all known encodings.
+func All() []*Encoding {
+ return []*Encoding{jsonEnc, yamlEnc}
+}
+
+// MapExtension returns the likely encoding for a given file extension.
+func MapExtension(ext string) *Encoding {
+ return extensions[strings.ToLower(ext)]
+}
+
+var (
+ jsonEnc = &Encoding{name: "json"}
+ yamlEnc = &Encoding{name: "yaml"}
+)
+
+// extensions maps a file extension to a Kind.
+var extensions = map[string]*Encoding{
+ ".json": jsonEnc,
+ ".jsonl": jsonEnc,
+ ".ndjson": jsonEnc,
+ ".yaml": yamlEnc,
+ ".yml": yamlEnc,
+}
