Merge branch 'master-upstream'

doc/javascript-target.md

@@ -154,6 +154,10 @@ In order to execute this listener, you would simply add the following lines to t
  antlr4.tree.ParseTreeWalker.DEFAULT.walk(printer, tree);
 ```
 
+## What about TypeScript?
+
+We currently do not have a TypeScript target, but Sam Harwell is [working on a port](https://github.com/tunnelvisionlabs/antlr4ts). [Here](https://github.com/ChuckJonas/extract-interface-ts) is Section 4.3 of [ANTLR 4 book](http://a.co/5jUJYmh) converted to typescript.
+
 ## How do I integrate my parser with ACE editor?
 
 This specific task is described in this [dedicated page](ace-javascript-target.md).

runtime/Go/antlr/file_stream.go

@@ -19,13 +19,19 @@ type FileStream struct {
 	filename string
 }
 
-func NewFileStream(fileName string) *FileStream {
+func NewFileStream(fileName string) (*FileStream, error) {
 
 	buf := bytes.NewBuffer(nil)
 
-	f, _ := os.Open(fileName) // Error handling elided for brevity.
+	f, err := os.Open(fileName)
-	io.Copy(buf, f)           // Error handling elided for brevity.
+	if err != nil {
-	f.Close()
+		return nil, err
+	}
+	defer f.Close()
+	err = io.Copy(buf, f)
+	if err != nil {
+		return nil, er
+	}
 
 	fs := new(FileStream)
 
@@ -34,7 +40,7 @@ func NewFileStream(fileName string) *FileStream {
 
 	fs.InputStream = NewInputStream(s)
 
-	return fs
+	return fs, nil
 
 }