comment editing

examples/line-filters/line-filters.go

@@ -24,26 +24,31 @@ func main() {
     rdr := bufio.NewReader(os.Stdin)
     out := os.Stdout
 
-    for {
     // `ReadString` returns the next string from the
     // input up to the given separator byte. We give the
     // newline byte `'\n'` as our separator so we'll get
     // successive input lines.
+    for {
         switch line, err := rdr.ReadString('\n'); err {
+
+        // If the read succeeded, write out out the
+        // uppercased line. Check for an error on the
+        // write as we do on the read.
         case nil:
-            // Write out the uppercased line, checking for an
-            // error on the write as we did on the read.
             ucl := strings.ToUpper(line)
             if _, err = out.WriteString(ucl); err != nil {
                 log.Println(err)
                 os.Exit(-1)
             }
-        case io.EOF:
+
         // The `EOF` error is expected when we reach the
         // end of input, so exit gracefully in that case.
+        case io.EOF:
             os.Exit(0)
+
+        // Otherwise there's a problem; print the
+        // error and exit with non-zero status.
         default:
-            // Otherwise there's a problem
             log.Println(err)
             os.Exit(-1)
         }