interval.go

package level2

import (
	// "fmt"
	"github.com/sfomuseum/go-edtf"
	"github.com/sfomuseum/go-edtf/common"
	"github.com/sfomuseum/go-edtf/re"
	//"strings"
)

/*

For Level 2 portions of a date within an interval may be designated as approximate, uncertain, or unspecified.

    Example 1                 ‘2004-06-~01/2004-06-~20’
    An interval in June 2004 beginning approximately the first and ending approximately the 20th
    Example 2                 ‘2004-06-XX/2004-07-03’
    An interval beginning on an unspecified day in June 2004 and ending July 3.


*/

func IsInterval(edtf_str string) bool {
	return re.Interval.MatchString(edtf_str)
}

func ParseInterval(edtf_str string) (*edtf.EDTFDate, error) {

	/*

		INTERVAL 2004-06-~01/2004-06-~20 13 2004-06-~01/2004-06-~20,,2004,,06,~,01,,2004,,06,~,20
		INTERVAL 2004-06-XX/2004-07-03 13 2004-06-XX/2004-07-03,,2004,,06,,XX,,2004,,07,,03

	*/

	if !re.Interval.MatchString(edtf_str) {
		return nil, edtf.Invalid(INTERVAL, edtf_str)
	}

	sp, err := common.DateSpanFromEDTF(edtf_str)

	if err != nil {
		return nil, err
	}

	d := &edtf.EDTFDate{
		Start:   sp.Start,
		End:     sp.End,
		EDTF:    edtf_str,
		Level:   LEVEL,
		Feature: INTERVAL,
	}

	return d, nil
}