Feature: parse fractional numbers (#20)

* Cosmetic simplification

* Support parsing fractional numbers

This commit supports parsing fractional timestamps like
1650628714.610705000. It considers the integer part only - no
rounding logic is applied.

* Fix spelling

cmd/epoch/main.go

@@ -82,9 +82,9 @@ func run(input string, now, calc string, unit, format, tz string, quiet bool) (s
 		return "", err
 	}
 
-	// If the input can be parsed as an int, we assume it's an epoch timestamp. Convert to formatted string.
-	if i, err := strconv.ParseInt(input, 10, 64); err == nil {
-		t := parseTimestamp(unit, i, quiet).In(location(tz))
+	// If the input can be parsed as a number, we assume it's an epoch timestamp. Convert to formatted string.
+	if i, err := strconv.ParseFloat(input, 64); err == nil {
+		t := parseTimestamp(unit, int64(i), quiet).In(location(tz))
 
 		if len(calculations) > 0 {
 			// when applying arithmetics here, return as timestamp again
@@ -122,7 +122,7 @@ func run(input string, now, calc string, unit, format, tz string, quiet bool) (s
 		return "", fmt.Errorf("can't use specific format when converting to timestamp (omit -format flag)")
 	}
 
-	// convert fromatted string to time type
+	// convert formatted string to time type
 	t, _, err := epoch.ParseFormatted(input)
 	if err != nil {
 		log.Fatalf("failed to convert input: %v", err)

epoch.go

@@ -61,7 +61,7 @@ func ToTimestamp(t time.Time, unit TimeUnit) (int64, error) {
 
 func abs(i int) int {
 	if i < 0 {
-		return i * -1
+		return -i
 	}
 	return i
 }