encoding/json: add JSON exporter
and use this in cmd/cue
The AST rewriter is somewhat specific to JSON.
Some parts may be moved to more general format
functionality later.
Closes #118
Change-Id: I530a7ee2a32b76b4709398039227d9c994316fda
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/3380
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/encoding/json/json_test.go b/encoding/json/json_test.go
new file mode 100644
index 0000000..26cafd2
--- /dev/null
+++ b/encoding/json/json_test.go
@@ -0,0 +1,143 @@
+// Copyright 2019 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 json
+
+import (
+ "bytes"
+ "fmt"
+ "io"
+ "strings"
+ "testing"
+
+ "cuelang.org/go/cue/ast"
+ "cuelang.org/go/cue/format"
+ "github.com/stretchr/testify/assert"
+)
+
+func TestExtract(t *testing.T) {
+ testCases := []struct {
+ name string
+ in string
+ out string
+ }{{
+ name: "no expand as JSON is not compact",
+ in: `{"a": 32}`,
+ out: `{a: 32}`,
+ }, {
+ name: "break across new lines",
+ in: `{"a":32,"b":[1,2],"c-d":"foo-bar-baz"}`,
+ out: `{
+ a: 32
+ b: [1, 2]
+ "c-d": "foo-bar-baz"
+}`,
+ }, {
+ name: "multiline string",
+ in: `"a\nb\uD803\uDE6D\nc\\\t\nd\/"`,
+ out: `"""
+ a
+ b` + "\U00010E6D" + `
+ c\\\t
+ d/
+ """`,
+ }, {
+ name: "multiline string indented",
+ in: `{"x":{"y":"a\nb\nc\nd"}}`,
+ out: `{
+ x: {
+ y: """
+ a
+ b
+ c
+ d
+ """
+ }
+}`,
+ }, {
+ name: "don't create multiline string for label",
+ in: `{"foo\nbar\nbaz\n": 2}`,
+ out: `{"foo\nbar\nbaz\n": 2}`,
+ }, {
+ name: "don't cap indentation",
+ in: `{"a":{"b":{"c":{"d":"a\nb\nc\nd"}}}}`,
+ out: `{
+ a: {
+ b: {
+ c: {
+ d: """
+ a
+ b
+ c
+ d
+ """
+ }
+ }
+ }
+}`,
+ }, {
+ name: "keep list formatting",
+ in: `[1,2,
+ 3]`,
+ out: "[1, 2,\n\t3]",
+ }, {
+ // TODO: format.Node doesn't break large lists, it probably should.
+ name: "large list",
+ in: `[11111111111,2222222222,3333333333,4444444444,5555555555,6666666666]`,
+ out: "[11111111111, 2222222222, 3333333333, 4444444444, 5555555555, 6666666666]",
+ }, {
+ name: "reflow large values unconditionally",
+ in: `{"a": "11111111112222222222333333333344444444445555555555"}`,
+ out: "{\n\ta: \"11111111112222222222333333333344444444445555555555\"\n}",
+ }, {
+ name: "invalid JSON",
+ in: `[3_]`,
+ out: "invalid JSON for file \"invalid JSON\": invalid character '_' after array element",
+ }}
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ out := &bytes.Buffer{}
+ e, err := Extract(tc.name, tc.in)
+ toString(out, e, err)
+ assert.Equal(t, tc.out, out.String())
+
+ out = &bytes.Buffer{}
+ d := NewDecoder(nil, tc.name, strings.NewReader(tc.in))
+ for {
+ e, err := d.Extract()
+ if err == io.EOF {
+ break
+ }
+ toString(out, e, err)
+ if err != nil {
+ break
+ }
+ }
+ assert.Equal(t, tc.out, out.String())
+ })
+ }
+}
+
+func toString(w *bytes.Buffer, e ast.Expr, err error) {
+ if err != nil {
+ fmt.Fprint(w, err)
+ return
+ }
+ b, err := format.Node(e)
+ if err != nil {
+ fmt.Fprint(w, err)
+ return
+ }
+ fmt.Fprint(w, string(b))
+}
