emitter: add pad_line_comments

apic.go

@@ -206,6 +206,14 @@ func yaml_emitter_set_indentless_block_sequence(emitter *yaml_emitter_t, indentl
 	emitter.indentless_block_sequence = indentless_block_sequence
 }
 
+// Set indent line comments.
+func yaml_emitter_set_indent_line_comments(emitter *yaml_emitter_t, indent_line_comments int) {
+	if indent_line_comments < 0 {
+		indent_line_comments = 1
+	}
+	emitter.indent_line_comments = indent_line_comments
+}
+
 ///*
 // * Destroy a token object.
 // */

emitterc.go

@@ -1147,8 +1147,11 @@ func yaml_emitter_process_line_comment(emitter *yaml_emitter_t) bool {
 		return true
 	}
 	if !emitter.whitespace {
-		if !put(emitter, ' ') {
-			return false
+		// Insert as many spaces before the line comment as requested.
+		for i := 0; i < emitter.indent_line_comments; i++ {
+			if !put(emitter, ' ') {
+				return false
+			}
 		}
 	}
 	if !yaml_emitter_write_comment(emitter, emitter.line_comment) {

encode.go

@@ -41,6 +41,7 @@ type encoder struct {
 func newEncoder() *encoder {
 	e := &encoder{}
 	yaml_emitter_initialize(&e.emitter)
+	yaml_emitter_set_indent_line_comments(&e.emitter, 1)
 	yaml_emitter_set_output_string(&e.emitter, &e.out)
 	yaml_emitter_set_unicode(&e.emitter, true)
 	return e
@@ -49,6 +50,7 @@ func newEncoder() *encoder {
 func newEncoderWithWriter(w io.Writer) *encoder {
 	e := &encoder{}
 	yaml_emitter_initialize(&e.emitter)
+	yaml_emitter_set_indent_line_comments(&e.emitter, 1)
 	yaml_emitter_set_output_writer(&e.emitter, w)
 	yaml_emitter_set_unicode(&e.emitter, true)
 	return e

formattest/encode_test.go

@@ -62,3 +62,14 @@ func TestDropMergeTag(t *testing.T) {
 		},
 	}.Run(t)
 }
+
+func TestIndentLineComments(t *testing.T) {
+	formatTestCase{
+		name:             "indent line comments",
+		folder:           "indent_line_comments",
+		configureDecoder: noopDecoder,
+		configureEncoder: func(enc *yaml.Encoder) {
+			enc.SetIndentLineComments(2)
+		},
+	}.Run(t)
+}

formattest/testdata/indent_line_comments/expected.yaml

@@ -0,0 +1 @@
+a: 1  # comment

formattest/testdata/indent_line_comments/input.yaml

@@ -0,0 +1 @@
+a: 1 # comment

yaml.go

@@ -323,6 +323,11 @@ func (e *Encoder) SetDropMergeTag(dropMergeTag bool) {
 	e.encoder.optDropMergeTag = dropMergeTag
 }
 
+// SetIndentLineComments changes the number of indentation spaces before line comments.
+func (e *Encoder) SetIndentLineComments(indentLineComments int) {
+	yaml_emitter_set_indent_line_comments(&e.encoder.emitter, indentLineComments)
+}
+
 // Close closes the encoder by writing any remaining data.
 // It does not write a stream terminating string "...".
 func (e *Encoder) Close() (err error) {

yamlh.go

@@ -738,6 +738,7 @@ type yaml_emitter_t struct {
 	explicit_document_start   bool         // Force an explicit document start
 	assume_folded_as_literal  bool         // Assume blocks were scanned as literals
 	indentless_block_sequence bool         // Do not indent block sequences
+	indent_line_comments      int          // The number of indentation spaces before line comments.
 
 	state  yaml_emitter_state_t   // The current emitter state.
 	states []yaml_emitter_state_t // The stack of states.