This tool creates String methods from constant definitions.
It's a time-saver designed to be used from go generate.
The methods generated are efficient, more so than one
is likely to create by hand.
Given
package date
type Day int
const (
Monday Day = iota
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
)
the command
stringer -type Day
will create the file day_string.go containing
package date
import "fmt"
var (
_Day_indexes = []uint8{6, 13, 22, 30, 36, 44, 50}
_Day_names = "MondayTuesdayWednesdayThursdayFridaySaturdaySunday"
)
func (i Day) String() string {
if i < 0 || i >= Day(len(_Day_indexes)) {
return fmt.Sprintf("Day(%d)", i)
}
hi := _Day_indexes[i]
lo := uint8(0)
if i > 0 {
lo = _Day_indexes[i-1]
}
return _Day_names[lo:hi]
}
There are several strategies for the created method chosen according to
the structure of the sequence of constants.
Handles integer types only, both signed and unsigned. That's probably
all that is needed.
Tests to follow, but the test structure will be large so sending this out
separately. The code has been heavily hand-tested but there are
some bugs. Don't depend on this until the tests are installed.
LGTM=gri
R=gri, josharian
CC=golang-codereviews
https://golang.org/cl/136180043
2c5c896732