Function ParseInterval

pkg/util/duration/duration.go:1052–1092

ParseInterval parses the given interval in the given style.

(
	style IntervalStyle, s string, itm types.IntervalTypeMetadata,
)

// ParseInterval parses the given interval in the given style.
func ParseInterval(
	style IntervalStyle, s string, itm types.IntervalTypeMetadata,
) (Duration, error) {
	// At this time the only supported interval formats are:
	// - SQL standard.
	// - Postgres compatible.
	// - iso8601 format (with designators only), see interval.go for
	//   sources of documentation.
	// - Golang time.parseDuration compatible.

	// If it's a blank string, exit early.
	if len(s) == 0 {
		return Duration{}, makeParseError(s, types.Interval, nil)
	}
	if s[0] == 'P' {
		// If it has a leading P we're most likely working with an iso8601
		// interval.
		dur, err := iso8601ToDuration(s)
		if err != nil {
			return Duration{}, makeParseError(s, types.Interval, err)
		}
		return dur, nil
	}
	if strings.IndexFunc(s, unicode.IsLetter) == -1 {
		// If it has no letter, then we're most likely working with a SQL standard
		// interval, as both postgres and golang have letter(s) and iso8601 has been tested.
		dur, err := sqlStdToDuration(s, itm)
		if err != nil {
			return Duration{}, makeParseError(s, types.Interval, err)
		}
		return dur, nil
	}

	// We're either a postgres string or a Go duration.
	// Our postgres syntax parser also supports golang, so just use that for both.
	dur, err := parseDuration(style, s, itm)
	if err != nil {
		return Duration{}, makeParseError(s, types.Interval, err)
	}
	return dur, nil
}

func makeParseError(s string, typ *types.T, err error) error {
	if err != nil {