From 4720196aaa67f9cf29ff277a66b56c38a0c7d753 Mon Sep 17 00:00:00 2001
From: Kyle Isom <coder@kyleisom.net>
Date: Tue, 5 Jul 2016 15:54:13 -0700
Subject: [PATCH] yamll: support reading from stdin.

---
 cmd/yamll/README  | 12 ++++++++++++
 cmd/yamll/main.go | 22 ++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/cmd/yamll/README b/cmd/yamll/README
index 77b3559..3e71c5d 100644
--- a/cmd/yamll/README
+++ b/cmd/yamll/README
@@ -1,3 +1,15 @@
 yamll: yaml linter
 
 Run this over YAML files to determine if they are well-formed or not.
+
+Usage: yamll [-hq] files...
+
+        For each file, yamll will make sure it is a well-formatted YAML
+        file.  Unless the -q option is passed, yamll will print the names
+        of each file and whether it was well-formed. With the -q option,
+        only malformed files are printed.
+
+	If the only command line argument is "-", yamll will read from
+	standard input. It is assumed the entirety of standard input is
+	a single file.
+
diff --git a/cmd/yamll/main.go b/cmd/yamll/main.go
index 8982348..8919876 100644
--- a/cmd/yamll/main.go
+++ b/cmd/yamll/main.go
@@ -42,6 +42,28 @@ func main() {
 		os.Exit(0)
 	}
 
+	if flag.NArg() == 1 && flag.Arg(0) == "-" {
+		path := "stdin"
+		in, err := ioutil.ReadAll(os.Stdin)
+		if err != nil {
+			errorf("%s FAILED: %s", path, err)
+			os.Exit(1)
+		}
+
+		var e empty
+		err = yaml.Unmarshal(in, &e)
+		if err != nil {
+			errorf("%s FAILED: %s", path, err)
+			os.Exit(1)
+		}
+
+		if !*quiet {
+			fmt.Printf("%s: OK\n", path)
+		}
+
+		os.Exit(0)
+	}
+
 	for _, path := range flag.Args() {
 		in, err := ioutil.ReadFile(path)
 		if err != nil {