Feature (v3): Add a function to set the desired line length of an Encoder

encode.go

@@ -540,3 +540,7 @@ func (e *encoder) node(node *Node, tail string) {
 		e.emitScalar(value, node.Anchor, tag, style, []byte(node.HeadComment), []byte(node.LineComment), []byte(node.FootComment), []byte(tail))
 	}
 }
+
+func (e *encoder) setWidth(width int) {
+	yaml_emitter_set_width(&e.emitter, width)
+}

encode_test.go

@@ -410,18 +410,21 @@ var marshalTests = []struct {
 		&marshalerType{&marshalerType{true}},
 		"true\n",
 	},
-
 	// Check indentation of maps inside sequences inside maps.
 	{
 		map[string]interface{}{"a": map[string]interface{}{"b": []map[string]int{{"c": 1, "d": 2}}}},
 		"a:\n    b:\n      - c: 1\n        d: 2\n",
 	},
-
 	// Strings with tabs were disallowed as literals (issue #471).
 	{
 		map[string]string{"a": "\tB\n\tC\n"},
 		"a: |\n    \tB\n    \tC\n",
 	},
+	// Ensure that strings wrap
+	{
+		map[string]string{"a": "abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 "},
+		"a: 'abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 abcdefghijklmnopqrstuvwxyz\n    ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 '\n",
+	},
 }
 
 func (s *S) TestMarshal(c *C) {
@@ -584,6 +587,28 @@ func (s *S) TestSetIndent(c *C) {
 	c.Assert(buf.String(), Equals, "a:\n        b:\n                c: d\n")
 }
 
+func (s *S) TestSetSmallWrapLength(c *C) {
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
+	enc.SetLineLength(10)
+	err := enc.Encode(map[string]interface{}{"a": "abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 "})
+	c.Assert(err, Equals, nil)
+	err = enc.Close()
+	c.Assert(err, Equals, nil)
+	c.Assert(buf.String(), Equals, "a: 'abcdefghijklmnopqrstuvwxyz\n    ABCDEFGHIJKLMNOPQRSTUVWXYZ\n    1234567890\n    abcdefghijklmnopqrstuvwxyz\n    ABCDEFGHIJKLMNOPQRSTUVWXYZ\n    1234567890 '\n")
+}
+
+func (s *S) TestSetNegativeWrapLength(c *C) {
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
+	enc.SetLineLength(-1)
+	err := enc.Encode(map[string]interface{}{"a": "abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 "})
+	c.Assert(err, Equals, nil)
+	err = enc.Close()
+	c.Assert(err, Equals, nil)
+	c.Assert(buf.String(), Equals, "a: 'abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 '\n")
+}
+
 func (s *S) TestSortedOutput(c *C) {
 	order := []interface{}{
 		false,

yaml.go

@@ -260,6 +260,12 @@ func (e *Encoder) SetIndent(spaces int) {
 	e.encoder.indent = spaces
 }
 
+// SetLineLength changes the desired line wrapping length.
+// if characters is negative, '1<<31 - 1' is used.
+func (e *Encoder) SetLineLength(characters int) {
+	e.encoder.setWidth(characters)
+}
+
 // Close closes the encoder by writing any remaining data.
 // It does not write a stream terminating string "...".
 func (e *Encoder) Close() (err error) {