cmd/cue/cmd: show output when requesting concrete

right now it just validated

Issue cue-lang#52

Change-Id: Ie34afea9b495b7b9cdfc81dd98ce685539d19407
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2179
Reviewed-by: Marcel van Lohuizen <mpvl@google.com>

cmd/cue/cmd/common.go

@@ -16,10 +16,7 @@ package cmd
 
 import (
 	"bytes"
-	"fmt"
-	"io"
 	"os"
-	"strings"
 
 	"cuelang.org/go/cue"
 	"cuelang.org/go/cue/build"
@@ -31,22 +28,11 @@ import (
 
 var runtime = &cue.Runtime{}
 
-// printHeader is a hacky and unprincipled way to sanatize the package path.
-func printHeader(w io.Writer, cwd, dir string) {
-	if cwd != "" {
-		if dir == cwd {
-			return
-		}
-		dir = strings.Replace(dir, cwd, ".", 1)
-	}
-	fmt.Fprintf(w, "--- %s\n", dir)
-}
-
 func exitIfErr(cmd *cobra.Command, inst *cue.Instance, err error, fatal bool) {
-	exitOnErr(cmd, inst.Dir, err, fatal)
+	exitOnErr(cmd, err, fatal)
 }
 
-func exitOnErr(cmd *cobra.Command, file string, err error, fatal bool) {
+func exitOnErr(cmd *cobra.Command, err error, fatal bool) {
 	if err == nil {
 		return
 	}
@@ -56,7 +42,6 @@ func exitOnErr(cmd *cobra.Command, file string, err error, fatal bool) {
 	}
 
 	w := &bytes.Buffer{}
-	printHeader(w, cwd, file)
 	errors.Print(w, err)
 
 	// TODO: do something more principled than this.

cmd/cue/cmd/eval.go

@@ -117,14 +117,28 @@ func runEval(cmd *cobra.Command, args []string) error {
 		if exprs == nil {
 			v := inst.Value()
 			if flagConcrete.Bool(cmd) {
-				err := v.Validate(cue.Concrete(true))
-				exitIfErr(cmd, inst, err, false)
-				continue
+				if err := v.Validate(cue.Concrete(true)); err != nil {
+					exitIfErr(cmd, inst, err, false)
+					continue
+				}
 			}
 			format.Node(w, getSyntax(v, syn), opts...)
 		}
 		for _, e := range exprs {
-			format.Node(w, getSyntax(inst.Eval(e), syn), opts...)
+			if len(exprs) > 1 {
+				fmt.Fprint(w, "// ")
+				format.Node(w, e)
+				fmt.Fprintln(w)
+			}
+			v := inst.Eval(e)
+			if flagConcrete.Bool(cmd) {
+				if err := v.Validate(cue.Concrete(true)); err != nil {
+					exitIfErr(cmd, inst, err, false)
+					continue
+				}
+			}
+			format.Node(w, getSyntax(v, syn), opts...)
+			fmt.Fprintln(w)
 		}
 	}
 	return nil

cmd/cue/cmd/eval_test.go

@@ -18,4 +18,12 @@ import "testing"
 
 func TestEval(t *testing.T) {
 	runCommand(t, newEvalCmd(), "eval")
+
+	cmd := newEvalCmd()
+	cmd.ParseFlags([]string{"-c", "-a"})
+	runCommand(t, cmd, "eval_conc")
+
+	cmd = newEvalCmd()
+	cmd.ParseFlags([]string{"-c", "-e", "b.a.b", "-e", "b.idx"})
+	runCommand(t, cmd, "eval_expr")
 }

cmd/cue/cmd/import.go

@@ -308,7 +308,7 @@ func runImport(cmd *cobra.Command, args []string) error {
 	})
 
 	err := group.Wait()
-	exitOnErr(cmd, "", err, true)
+	exitOnErr(cmd, err, true)
 	return nil
 }
 

cmd/cue/cmd/testdata/hello/eval_conc.out

@@ -0,0 +1,2 @@
+who:     "World"
+message: "Hello World!"

cmd/cue/cmd/testdata/loaderr/loaderr.out

@@ -1,3 +1,2 @@
---- non-existing
 cannot find package "non-existing"
 terminating because of errors

cmd/cue/cmd/testdata/partial/eval_conc.out

@@ -0,0 +1,2 @@
+: invalid non-ground value string (must be concrete int|string):
+    ./testdata/partial/partial.cue:7:7

cmd/cue/cmd/testdata/partial/eval_expr.out

@@ -0,0 +1,5 @@
+// b.a.b
+4
+// b.idx
+: invalid non-ground value string (must be concrete int|string):
+    ./testdata/partial/partial.cue:7:7