Date ParseISO & AutoParse now accept a date-time input (time is ignored)

Author: rickb777

parse.go

@@ -7,6 +7,7 @@ package date
 import (
 	"errors"
 	"fmt"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -92,6 +93,9 @@ func MustParseISO(value string) Date {
 // with possibly extra year digits beyond the prescribed four-digit minimum
 // and with a + or - sign prefix (e.g. , "+12345-06-07", "-0987-06-05").
 //
+// If a time field is present, it is ignored. For example, "2018-02-03T00:00:00Z" is parsed
+// as 3rd February 2018.
+//
 // Note that ParseISO is a little looser than the ISO 8601 standard and will
 // be happy to parse dates with a year longer in length than the four-digit minimum even
 // if they are missing the + sign prefix.
@@ -102,15 +106,23 @@ func MustParseISO(value string) Date {
 //
 // Background: https://en.wikipedia.org/wiki/ISO_8601#Dates
 func ParseISO(value string) (Date, error) {
-	if len(value) < 8 {
-		return Date{}, fmt.Errorf("Date.ParseISO: cannot parse %q: incorrect length", value)
-	}
-
 	abs := value
 	if value[0] == '+' || value[0] == '-' {
 		abs = value[1:]
 	}
 
+	if len(abs) < 8 {
+		return Date{}, fmt.Errorf("date.ParseISO: cannot parse %q: incorrect length", value)
+	}
+
+	tee := strings.IndexByte(abs, 'T')
+	if tee == 8 || tee == 10 {
+		if !timeRegex1.MatchString(abs[tee:]) && !timeRegex2.MatchString(abs[tee:]) {
+			return Date{}, fmt.Errorf("date.ParseISO: date-time %q: not a time", value)
+		}
+		abs = abs[:tee]
+	}
+
 	dash1 := strings.IndexByte(abs, '-')
 	fm1 := dash1 + 1
 	fm2 := dash1 + 3
@@ -125,12 +137,12 @@ func ParseISO(value string) (Date, error) {
 		fd1 = 6
 		fd2 = 8
 	} else if abs[fm2] != '-' {
-		return Date{}, fmt.Errorf("Date.ParseISO: cannot parse %q: incorrect syntax", value)
+		return Date{}, fmt.Errorf("date.ParseISO: cannot parse %q: incorrect syntax", value)
 	}
 	//fmt.Printf("%s %d %d %d %d %d\n", value, dash1, fm1, fm2, fd1, fd2)
 
 	if len(abs) != fd2 {
-		return Date{}, fmt.Errorf("Date.ParseISO: cannot parse %q: incorrect length", value)
+		return Date{}, fmt.Errorf("date.ParseISO: cannot parse %q: incorrect length", value)
 	}
 
 	year, err := parseField(value, abs[:dash1], "year", 4, -1)
@@ -157,13 +169,18 @@ func ParseISO(value string) (Date, error) {
 	return Date{encode(t)}, nil
 }
 
+var (
+	timeRegex1 = regexp.MustCompile("^T[0-9][0-9].[0-9][0-9].[0-9][0-9]")
+	timeRegex2 = regexp.MustCompile("^T[0-9]{2,6}")
+)
+
 func parseField(value, field, name string, minLength, requiredLength int) (int, error) {
 	if (minLength > 0 && len(field) < minLength) || (requiredLength > 0 && len(field) != requiredLength) {
-		return 0, fmt.Errorf("Date.ParseISO: cannot parse %q: invalid %s", value, name)
+		return 0, fmt.Errorf("date.ParseISO: cannot parse %q: invalid %s", value, name)
 	}
 	number, err := strconv.Atoi(field)
 	if err != nil {
-		return 0, fmt.Errorf("Date.ParseISO: cannot parse %q: invalid %s", value, name)
+		return 0, fmt.Errorf("date.ParseISO: cannot parse %q: invalid %s", value, name)
 	}
 	return number, nil
 }

parse_test.go

@@ -24,7 +24,11 @@ func TestAutoParse(t *testing.T) {
 		{"1969.12.31", 1969, time.December, 31},
 		{"1969-12-31", 1969, time.December, 31},
 		{"2000-02-28", 2000, time.February, 28},
+		{"20000228", 2000, time.February, 28},
+		{"2018-02-03T00:00:00Z", 2018, time.February, 3}, // datetime is allowed
+		{"20180203T000000Z", 2018, time.February, 3},     // datetime is allowed
 		{"+2000-02-29", 2000, time.February, 29},
+		{"+20000229", 2000, time.February, 29},
 		{"+02000-03-01", 2000, time.March, 1},
 		{"+002004-02-28", 2004, time.February, 28},
 		{"2004-02-29", 2004, time.February, 29},
@@ -54,7 +58,9 @@ func TestAutoParse(t *testing.T) {
 			t.Errorf("ParseISO(%v) == %v, want (%v, %v, %v)", c.value, d, c.year, c.month, c.day)
 		}
 	}
+}
 
+func TestAutoParse_errors(t *testing.T) {
 	badCases := []string{
 		"1234-05",
 		"1234-5-6",
@@ -91,10 +97,15 @@ func TestParseISO(t *testing.T) {
 		day   int
 	}{
 		{"1969-12-31", 1969, time.December, 31},
+		{"19691231", 1969, time.December, 31},
+		{"2018-02-03T00:00:00Z", 2018, time.February, 3}, // datetime is allowed
+		{"20180203T000000Z", 2018, time.February, 3},     // datetime is allowed
 		{"+1970-01-01", 1970, time.January, 1},
 		{"+01970-01-02", 1970, time.January, 2},
 		{"2000-02-28", 2000, time.February, 28},
+		{"20000228", 2000, time.February, 28},
 		{"+2000-02-29", 2000, time.February, 29},
+		{"+20000229", 2000, time.February, 29},
 		{"+02000-03-01", 2000, time.March, 1},
 		{"+002004-02-28", 2004, time.February, 28},
 		{"2004-02-29", 2004, time.February, 29},
@@ -125,7 +136,9 @@ func TestParseISO(t *testing.T) {
 			t.Errorf("ParseISO(%v) == %v, want (%v, %v, %v)", c.value, d, c.year, c.month, c.day)
 		}
 	}
+}
 
+func TestParseISO_errors(t *testing.T) {
 	badCases := []string{
 		"1234-05",
 		"1234-5-6",
@@ -143,6 +156,8 @@ func TestParseISO(t *testing.T) {
 		"+10-11-12",
 		"+100-02-03",
 		"-123-05-06",
+		"2018-02-03T0:0:0Z",
+		"2018-02-03T0Z",
 	}
 	for _, c := range badCases {
 		d, err := ParseISO(c)
@@ -205,7 +220,9 @@ func TestParse(t *testing.T) {
 			t.Errorf("Parse(%v) == %v, want (%v, %v, %v)", c.value, d, c.year, c.month, c.day)
 		}
 	}
+}
 
+func TestParse_errors(t *testing.T) {
 	// Test inability to parse ISO 8601 expanded year format
 	badCases := []string{
 		"+1234-05-06",