Respect string Style in Lua encoder

Lua has 'single', "double" and [[ long ]] strings.

pkg/yqlib/encoder_lua.go

@@ -80,7 +80,28 @@ func (le *luaEncoder) PrintLeadingContent(writer io.Writer, content string) erro
 }
 
 func (le *luaEncoder) encodeString(writer io.Writer, node *yaml.Node) error {
-	return writeString(writer, "\""+le.escape.Replace(node.Value)+"\"")
+	quote := "\""
+	switch node.Style {
+	case yaml.LiteralStyle, yaml.FoldedStyle, yaml.FlowStyle:
+		for i := 0; i < 10; i++ {
+			if !strings.Contains(node.Value, "]"+strings.Repeat("=", i)+"]") {
+				err := writeString(writer, "["+strings.Repeat("=", i)+"[\n")
+				if err != nil {
+					return err
+				}
+				err = writeString(writer, node.Value)
+				if err != nil {
+					return err
+				}
+				return writeString(writer, "]"+strings.Repeat("=", i)+"]")
+			}
+		}
+	case yaml.SingleQuotedStyle:
+		quote = "'"
+
+		// falltrough to regular ol' string
+	}
+	return writeString(writer, quote+le.escape.Replace(node.Value)+quote)
 }
 
 func (le *luaEncoder) writeIndent(writer io.Writer) error {

pkg/yqlib/lua_test.go

@@ -47,8 +47,8 @@ numbers: [123,456]
 	{
 		skipDoc:      true,
 		description:  "Scalar str",
-		input:        "str: |\n  foo\n  bar\n",
+		input:        "str: |\n  foo\n  bar\nanother: 'single'\nand: \"double\"",
-		expected:     "return {\n\t[\"str\"] = \"foo\\nbar\\n\";\n};\n",
+		expected:     "return {\n\t[\"str\"] = [[\nfoo\nbar\n]];\n\t[\"another\"] = 'single';\n\t[\"and\"] = \"double\";\n};\n",
 		scenarioType: "encode",
 	},
 	{