Add GopherJS compiler version and command to print it. (#501)

dmitshur · web-flow · commit 45518c130e5b · 2016-08-21T15:08:15.000-07:00
The version being referred to is the GopherJS compiler version, not not the GopherJS build tool. That's why the canonical version string is located in the compiler package. The build tool's version is less important and it effectively takes on the version of the compiler. Helps #500.
diff --git a/compiler/version_check.go b/compiler/version_check.go
@@ -4,3 +4,6 @@
 package compiler
 
 const ___GOPHERJS_REQUIRES_GO_VERSION_1_7___ = true
+
+// Version is the GopherJS compiler version string.
+const Version = "1.7-1"
diff --git a/tool.go b/tool.go
@@ -508,11 +508,24 @@ func main() {
 		fmt.Fprintln(os.Stderr, http.Serve(tcpKeepAliveListener{ln.(*net.TCPListener)}, sourceFiles))
 	}
 
+	cmdVersion := &cobra.Command{
+		Use:   "version",
+		Short: "print GopherJS compiler version",
+	}
+	cmdVersion.Run = func(cmd *cobra.Command, args []string) {
+		if len(args) > 0 {
+			cmdServe.HelpFunc()(cmd, args)
+			os.Exit(1)
+		}
+
+		fmt.Printf("GopherJS %s\n", compiler.Version)
+	}
+
 	rootCmd := &cobra.Command{
 		Use:  "gopherjs",
 		Long: "GopherJS is a tool for compiling Go source code to JavaScript.",
 	}
-	rootCmd.AddCommand(cmdBuild, cmdGet, cmdInstall, cmdRun, cmdTest, cmdServe)
+	rootCmd.AddCommand(cmdBuild, cmdGet, cmdInstall, cmdRun, cmdTest, cmdServe, cmdVersion)
 	rootCmd.Execute()
 }
 
