API: Add value flags for controlling scalar output style.

These allow plain, single quotes, and double quotes styles.

include/cyaml/cyaml.h

@@ -259,6 +259,63 @@ typedef enum cyaml_flag {
  * \ref cyaml_strval strings.
  */
  CYAML_FLAG_CASE_INSENSITIVE = (1 << 8),
+ /**
+ * When saving, emit scalar value with plain style (no quotes).
+ *
+ * \note This is ignored if the value is non-scaler.
+ *
+ * \note In cases where conflicting scalar style flags are set, the
+ * the one with the highest precedence is used. From lowest to
+ * highest precedence:
+ * \ref CYAML_FLAG_SCALAR_PLAIN,
+ * \ref CYAML_FLAG_SCALAR_FOLDED,
+ * \ref CYAML_FLAG_SCALAR_LITERAL,
+ * \ref CYAML_FLAG_SCALAR_QUOTE_SINGLE,
+ * \ref CYAML_FLAG_SCALAR_QUOTE_DOUBLE,
+ *
+ * If none of these are set, libyaml's default behaviour is used.
+ */
+ CYAML_FLAG_SCALAR_PLAIN = (1 << 9),
+ /**
+ * When saving, emit scalar value with folded style:
+ *
+ * ```yaml
+ * string: >
+ * This string
+ * really has no line breaks!
+ * ```
+ *
+ * See the notes for \ref CYAML_FLAG_SCALAR_PLAIN for applicability
+ * and precedence.
+ */
+ CYAML_FLAG_SCALAR_FOLDED = (1 << 10),
+ /**
+ * When saving, emit scalar value with literal style:
+ *
+ * ```yaml
+ * string: |
+ * This is a
+ * multi-line string!
+ * ```
+ *
+ * See the notes for \ref CYAML_FLAG_SCALAR_PLAIN for applicability
+ * and precedence.
+ */
+ CYAML_FLAG_SCALAR_LITERAL = (1 << 11),
+ /**
+ * When saving, emit scalar value with single quotes (`'`).
+ *
+ * See the notes for \ref CYAML_FLAG_SCALAR_PLAIN for applicability
+ * and precedence.
+ */
+ CYAML_FLAG_SCALAR_QUOTE_SINGLE = (1 << 12),
+ /**
+ * When saving, emit scalar value with double quotes (`"`).
+ *
+ * See the notes for \ref CYAML_FLAG_SCALAR_PLAIN for applicability
+ * and precedence.
+ */
+ CYAML_FLAG_SCALAR_QUOTE_DOUBLE = (1 << 13),
 } cyaml_flag_e;
 
 /**