cmd/cue/cmd: support -e for export
Closes #240
Change-Id: Ie6a28d355a1572177bfe558976469f2d1013f48c
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/5000
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cmd/cue/cmd/export.go b/cmd/cue/cmd/export.go
index 4a65036..9403070 100644
--- a/cmd/cue/cmd/export.go
+++ b/cmd/cue/cmd/export.go
@@ -22,6 +22,8 @@
"github.com/spf13/cobra"
"cuelang.org/go/cue"
+ "cuelang.org/go/cue/ast"
+ "cuelang.org/go/cue/parser"
"cuelang.org/go/pkg/encoding/yaml"
)
@@ -93,6 +95,8 @@
flagMedia.Add(cmd)
cmd.Flags().Bool(string(flagEscape), false, "use HTML escaping")
+ cmd.Flags().StringArrayP(string(flagExpression), "e", nil, "export this expression only")
+
cmd.Flags().StringArrayP(string(flagTags), "t", nil,
"set the value of a tagged field")
@@ -103,25 +107,49 @@
instances := buildFromArgs(cmd, args)
w := cmd.OutOrStdout()
+ var exprs []ast.Expr
+ for _, e := range flagExpression.StringArray(cmd) {
+ expr, err := parser.ParseExpr("<expression flag>", e)
+ if err != nil {
+ return err
+ }
+ exprs = append(exprs, expr)
+ }
+
+ count := 0
+
for _, inst := range instances {
root := inst.Value()
- switch media := flagMedia.String(cmd); media {
- case "json":
- err := outputJSON(cmd, w, root)
+ if exprs == nil {
+ err := exportValue(cmd, w, root, count)
exitIfErr(cmd, inst, err, true)
- case "text":
- err := outputText(w, root)
+ count++
+ continue
+ }
+ for _, e := range exprs {
+ v := inst.Eval(e)
+ exitIfErr(cmd, inst, v.Err(), true)
+ err := exportValue(cmd, w, v, count)
+ count++
exitIfErr(cmd, inst, err, true)
- case "yaml":
- err := outputYAML(w, root)
- exitIfErr(cmd, inst, err, true)
- default:
- return fmt.Errorf("export: unknown format %q", media)
}
}
return nil
}
+func exportValue(cmd *Command, w io.Writer, v cue.Value, i int) error {
+ switch media := flagMedia.String(cmd); media {
+ case "json":
+ return outputJSON(cmd, w, v)
+ case "text":
+ return outputText(w, v)
+ case "yaml":
+ return outputYAML(w, v, i)
+ default:
+ return fmt.Errorf("export: unknown format %q", media)
+ }
+}
+
func outputJSON(cmd *Command, w io.Writer, v cue.Value) error {
e := json.NewEncoder(w)
e.SetIndent("", " ")
@@ -146,7 +174,10 @@
return err
}
-func outputYAML(w io.Writer, v cue.Value) error {
+func outputYAML(w io.Writer, v cue.Value, i int) error {
+ if i > 0 {
+ fmt.Fprintln(w, "---")
+ }
str, err := yaml.Marshal(v)
if err != nil {
return err
diff --git a/cmd/cue/cmd/testdata/script/export_expr.txt b/cmd/cue/cmd/testdata/script/export_expr.txt
new file mode 100644
index 0000000..445d471
--- /dev/null
+++ b/cmd/cue/cmd/testdata/script/export_expr.txt
@@ -0,0 +1,10 @@
+cue export data.cue -e a+c -e d.e.f --out yaml
+cmp stdout expect-stdout
+-- expect-stdout --
+4
+---
+jam
+-- data.cue --
+a: 1
+c: 3
+d: e: f: "jam"
