pkg/storage: expose os.Stdin's Close and ReadAt methods

pkg/storage/stdio.go

@@ -20,7 +20,7 @@ func (*StdioEngine) Get(_ context.Context, u *URI) (Reader, error) {
 	if u.Scheme != "stdio" || (u.Path != "stdin" && u.Path != "") {
 		return nil, fmt.Errorf("cannot read from %q", u)
 	}
-	return &notSupportedReaderAt{io.NopCloser(os.Stdin)}, nil
+	return os.Stdin, nil
 }
 
 func (*StdioEngine) Put(ctx context.Context, u *URI) (io.WriteCloser, error) {

sio/anyio/ztests/csup.yaml

@@ -1,12 +1,17 @@
 script: |
   super -f csup -o f -
   super -s f
+  echo // standard input
+  super -s -c 'from "stdio:stdin"' < f
 
 inputs:
   - name: stdin
-    data: &stdin |
+    data: |
       {a:1}
 
 outputs:
   - name: stdout
-    data: *stdin
+    data: |
+      {a:1}
+      // standard input
+      {a:1}

sio/anyio/ztests/parquet.yaml

@@ -1,12 +1,17 @@
 script: |
   super -f parquet -o f -
   super -s f
+  echo // standard input
+  super -s -c 'from "stdio:stdin"' < f
 
 inputs:
   - name: stdin
-    data: &stdin |
+    data: |
       {a:1}
 
 outputs:
   - name: stdout
-    data: *stdin
+    data: |
+      {a:1}
+      // standard input
+      {a:1}