parserc.go

		implicit:   true,
		style:      yaml_style_t(yaml_PLAIN_SCALAR_STYLE),
	}
	return true
}

var default_tag_directives = []yaml_tag_directive_t{
	{[]byte("!"), []byte("!")},
	{[]byte("!!"), []byte("tag:yaml.org,2002:")},
}

// Parse directives.
func yaml_parser_process_directives(parser *yaml_parser_t,
	version_directive_ref **yaml_version_directive_t,
	tag_directives_ref *[]yaml_tag_directive_t) bool {

	var version_directive *yaml_version_directive_t
	var tag_directives []yaml_tag_directive_t

	token := peek_token(parser)
	if token == nil {
		return false
	}

	for token.typ == yaml_VERSION_DIRECTIVE_TOKEN || token.typ == yaml_TAG_DIRECTIVE_TOKEN {
		if token.typ == yaml_VERSION_DIRECTIVE_TOKEN {
			if version_directive != nil {
				yaml_parser_set_parser_error(parser,
					"found duplicate %YAML directive", token.start_mark)
				return false
			}
			if token.major != 1 || token.minor != 1 {
				yaml_parser_set_parser_error(parser,
					"found incompatible YAML document", token.start_mark)
				return false
			}
			version_directive = &yaml_version_directive_t{
				major: token.major,
				minor: token.minor,
			}
		} else if token.typ == yaml_TAG_DIRECTIVE_TOKEN {
			value := yaml_tag_directive_t{
				handle: token.value,
				prefix: token.prefix,
			}
			if !yaml_parser_append_tag_directive(parser, value, false, token.start_mark) {
				return false
			}
			tag_directives = append(tag_directives, value)
		}

		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
	}

	for i := range default_tag_directives {
		if !yaml_parser_append_tag_directive(parser, default_tag_directives[i], true, token.start_mark) {
			return false
		}
	}

	if version_directive_ref != nil {
		*version_directive_ref = version_directive
	}
	if tag_directives_ref != nil {
		*tag_directives_ref = tag_directives
	}
	return true
}

// Append a tag directive to the directives stack.
func yaml_parser_append_tag_directive(parser *yaml_parser_t, value yaml_tag_directive_t, allow_duplicates bool, mark yaml_mark_t) bool {
	for i := range parser.tag_directives {
		if bytes.Equal(value.handle, parser.tag_directives[i].handle) {
			if allow_duplicates {
				return true
			}
			return yaml_parser_set_parser_error(parser, "found duplicate %TAG directive", mark)
		}
	}

	// [Go] I suspect the copy is unnecessary. This was likely done
	// because there was no way to track ownership of the data.
	value_copy := yaml_tag_directive_t{
		handle: make([]byte, len(value.handle)),
		prefix: make([]byte, len(value.prefix)),
	}
	copy(value_copy.handle, value.handle)
	copy(value_copy.prefix, value.prefix)
	parser.tag_directives = append(parser.tag_directives, value_copy)
	return true
}