mirror of
https://github.com/golang/go
synced 2024-11-22 00:44:39 -07:00
d482c163be
This shortens, simplifies and regularizes the code significantly.
(Improvements to reflect could make another step.)
Passes all.bash.
One semantic change occurs: The String() method changes
behavior. It used to run only for string formats such as %s and %q.
Instead, it now runs whenever the item has the method and the
result is then processed by the format as a string. Besides the
regularization, this has three effects:
1) width is honored for String() items
2) %x works for String() items
3) implementations of String that merely recur will recur forever
Regarding point 3, example from the updated documentation:
type X int
func (x X) String() string { return Sprintf("%d", x) }
should cast the value before recurring:
func (x X) String() string { return Sprintf("%d", int(x)) }
R=rsc
CC=golang-dev
https://golang.org/cl/1613045
30 lines
531 B
Go
30 lines
531 B
Go
// $G $D/$F.go && $L $F.$A && ./$A.out
|
|
|
|
// Copyright 2009 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package main
|
|
|
|
import "fmt"
|
|
|
|
type T int
|
|
|
|
func (t T) String() string { return fmt.Sprintf("T%d", int(t)) }
|
|
|
|
const (
|
|
A T = 1 << (1 << iota)
|
|
B
|
|
C
|
|
D
|
|
E
|
|
)
|
|
|
|
func main() {
|
|
s := fmt.Sprintf("%v %v %v %v %v", A, B, C, D, E)
|
|
if s != "T2 T4 T16 T256 T65536" {
|
|
println("type info didn't propagate in const: got", s)
|
|
panic("fail")
|
|
}
|
|
}
|