Fixes #191.

This was a minor change; the offending function was just wrapping
another function that already properly returned an error value.

Just deleted the "bad" function and renamed the better one.

This is the fix only. The test updates will be in a different
commit to make this change easier to review.

cell.go

@@ -68,7 +68,7 @@ func (c *Cell) SetString(s string) {
 }
 
 // String returns the value of a Cell as a string.
-func (c *Cell) String() string {
+func (c *Cell) String() (string, error) {
 	return c.FormattedValue()
 }
 
@@ -291,11 +291,11 @@ func (c *Cell) formatToInt(format string) (string, error) {
 	return fmt.Sprintf(format, int(f)), nil
 }
 
-// SafeFormattedValue returns a value, and possibly an error condition
+// FormattedValue returns a value, and possibly an error condition
 // from a Cell.  If it is possible to apply a format to the cell
 // value, it will do so, if not then an error will be returned, along
 // with the raw value of the Cell.
-func (c *Cell) SafeFormattedValue() (string, error) {
+func (c *Cell) FormattedValue() (string, error) {
 	var numberFormat = c.GetNumberFormat()
 	if isTimeFormat(numberFormat) {
 		return parseTime(c)
@@ -348,17 +348,6 @@ func (c *Cell) SafeFormattedValue() (string, error) {
 
 }
 
-// FormattedValue returns the formatted version of the value.
-// If it's a string type, c.Value will just be returned. Otherwise,
-// it will attempt to apply Excel formatting to the value.
-func (c *Cell) FormattedValue() string {
-	value, err := c.SafeFormattedValue()
-	if err != nil {
-		return err.Error()
-	}
-	return value
-}
-
 // parseTime returns a string parsed using time.Time
 func parseTime(c *Cell) (string, error) {
 	f, err := strconv.ParseFloat(c.Value, 64)

file.go

@@ -312,7 +312,11 @@ func (file *File) ToSlice() (output [][][]string, err error) {
 			}
 			r := []string{}
 			for _, cell := range row.Cells {
-				r = append(r, cell.String())
+				str, err := cell.String()
+				if err != nil {
+					return output, err
+				}
+				r = append(r, str)
 			}
 			s = append(s, r)
 		}