iota can be part of an expression and
expressions can be implicitly repeated, it is easy to build intricate
sets of values.
-
-type ByteSize float64
+type ByteSize float64
+
const (
- _ = iota // ignore first value by assigning to blank identifier
- KB ByteSize = 1<<(10*iota)
+ _ = iota // ignore first value by assigning to blank identifier
+ KB ByteSize = 1 << (10 * iota)
MB
GB
TB
@@ -1641,27 +1642,27 @@ The ability to attach a method such as String to a
type makes it possible for such values to format themselves
automatically for printing, even as part of a general type.
-
-func (b ByteSize) String() string {
+func (b ByteSize) String() string {
switch {
case b >= YB:
- return fmt.Sprintf("%.2fYB", float64(b/YB))
+ return fmt.Sprintf("%.2fYB", float64(b/YB))
case b >= ZB:
- return fmt.Sprintf("%.2fZB", float64(b/ZB))
+ return fmt.Sprintf("%.2fZB", float64(b/ZB))
case b >= EB:
- return fmt.Sprintf("%.2fEB", float64(b/EB))
+ return fmt.Sprintf("%.2fEB", float64(b/EB))
case b >= PB:
- return fmt.Sprintf("%.2fPB", float64(b/PB))
+ return fmt.Sprintf("%.2fPB", float64(b/PB))
case b >= TB:
- return fmt.Sprintf("%.2fTB", float64(b/TB))
+ return fmt.Sprintf("%.2fTB", float64(b/TB))
case b >= GB:
- return fmt.Sprintf("%.2fGB", float64(b/GB))
+ return fmt.Sprintf("%.2fGB", float64(b/GB))
case b >= MB:
- return fmt.Sprintf("%.2fMB", float64(b/MB))
+ return fmt.Sprintf("%.2fMB", float64(b/MB))
case b >= KB:
- return fmt.Sprintf("%.2fKB", float64(b/KB))
+ return fmt.Sprintf("%.2fKB", float64(b/KB))
}
- return fmt.Sprintf("%.2fB", float64(b))
+ return fmt.Sprintf("%.2fB", float64(b))
}
@@ -1812,8 +1813,8 @@ by the routines in package sort if it implements
and it could also have a custom formatter.
In this contrived example Sequence satisfies both.
-
-type Sequence []int
+type Sequence []int
// Methods required by sort.Interface.
func (s Sequence) Len() int {
@@ -1829,14 +1830,14 @@ func (s Sequence) Swap(i, j int) {
// Method for printing - sorts the elements before printing.
func (s Sequence) String() string {
sort.Sort(s)
- str := "["
+ str := "["
for i, elem := range s {
if i > 0 {
- str += " "
+ str += " "
}
str += fmt.Sprint(elem)
}
- return str + "]"
+ return str + "]"
}
diff --git a/doc/effective_go.tmpl b/doc/effective_go.tmpl
index 98ef6428653..66078948203 100644
--- a/doc/effective_go.tmpl
+++ b/doc/effective_go.tmpl
@@ -1622,48 +1622,13 @@ enumerator. Since iota can be part of an expression and
expressions can be implicitly repeated, it is easy to build intricate
sets of values.
-
-type ByteSize float64
-const (
- _ = iota // ignore first value by assigning to blank identifier
- KB ByteSize = 1<<(10*iota)
- MB
- GB
- TB
- PB
- EB
- ZB
- YB
-)
-
+{{code "progs/eff_bytesize.go" `/^type ByteSize/` `/^\)/`}}
The ability to attach a method such as String to a
type makes it possible for such values to format themselves
automatically for printing, even as part of a general type.
-
-func (b ByteSize) String() string {
- switch {
- case b >= YB:
- return fmt.Sprintf("%.2fYB", float64(b/YB))
- case b >= ZB:
- return fmt.Sprintf("%.2fZB", float64(b/ZB))
- case b >= EB:
- return fmt.Sprintf("%.2fEB", float64(b/EB))
- case b >= PB:
- return fmt.Sprintf("%.2fPB", float64(b/PB))
- case b >= TB:
- return fmt.Sprintf("%.2fTB", float64(b/TB))
- case b >= GB:
- return fmt.Sprintf("%.2fGB", float64(b/GB))
- case b >= MB:
- return fmt.Sprintf("%.2fMB", float64(b/MB))
- case b >= KB:
- return fmt.Sprintf("%.2fKB", float64(b/KB))
- }
- return fmt.Sprintf("%.2fB", float64(b))
-}
-
+{{code "progs/eff_bytesize.go" `/^func.*ByteSize.*String/` `/^}/`}}
(The float64 conversions prevent Sprintf
from recurring back through the String method for
@@ -1812,33 +1777,7 @@ by the routines in package sort if it implements
and it could also have a custom formatter.
In this contrived example Sequence satisfies both.
-
-type Sequence []int
-
-// Methods required by sort.Interface.
-func (s Sequence) Len() int {
- return len(s)
-}
-func (s Sequence) Less(i, j int) bool {
- return s[i] < s[j]
-}
-func (s Sequence) Swap(i, j int) {
- s[i], s[j] = s[j], s[i]
-}
-
-// Method for printing - sorts the elements before printing.
-func (s Sequence) String() string {
- sort.Sort(s)
- str := "["
- for i, elem := range s {
- if i > 0 {
- str += " "
- }
- str += fmt.Sprint(elem)
- }
- return str + "]"
-}
-
+{{code "progs/eff_sequence.go" `/^type/` "$"}}
Conversions
diff --git a/doc/progs/eff_bytesize.go b/doc/progs/eff_bytesize.go
new file mode 100644
index 00000000000..bcfde1a5a35
--- /dev/null
+++ b/doc/progs/eff_bytesize.go
@@ -0,0 +1,47 @@
+// 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 ByteSize float64
+
+const (
+ _ = iota // ignore first value by assigning to blank identifier
+ KB ByteSize = 1 << (10 * iota)
+ MB
+ GB
+ TB
+ PB
+ EB
+ ZB
+ YB
+)
+
+func (b ByteSize) String() string {
+ switch {
+ case b >= YB:
+ return fmt.Sprintf("%.2fYB", float64(b/YB))
+ case b >= ZB:
+ return fmt.Sprintf("%.2fZB", float64(b/ZB))
+ case b >= EB:
+ return fmt.Sprintf("%.2fEB", float64(b/EB))
+ case b >= PB:
+ return fmt.Sprintf("%.2fPB", float64(b/PB))
+ case b >= TB:
+ return fmt.Sprintf("%.2fTB", float64(b/TB))
+ case b >= GB:
+ return fmt.Sprintf("%.2fGB", float64(b/GB))
+ case b >= MB:
+ return fmt.Sprintf("%.2fMB", float64(b/MB))
+ case b >= KB:
+ return fmt.Sprintf("%.2fKB", float64(b/KB))
+ }
+ return fmt.Sprintf("%.2fB", float64(b))
+}
+
+func main() {
+ fmt.Println(YB, ByteSize(1e13))
+}
diff --git a/doc/progs/eff_sequence.go b/doc/progs/eff_sequence.go
new file mode 100644
index 00000000000..11c885abf82
--- /dev/null
+++ b/doc/progs/eff_sequence.go
@@ -0,0 +1,42 @@
+// 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"
+ "sort"
+)
+
+func main() {
+ seq := Sequence{6, 2, -1, 44, 16}
+ sort.Sort(seq)
+ fmt.Println(seq)
+}
+
+type Sequence []int
+
+// Methods required by sort.Interface.
+func (s Sequence) Len() int {
+ return len(s)
+}
+func (s Sequence) Less(i, j int) bool {
+ return s[i] < s[j]
+}
+func (s Sequence) Swap(i, j int) {
+ s[i], s[j] = s[j], s[i]
+}
+
+// Method for printing - sorts the elements before printing.
+func (s Sequence) String() string {
+ sort.Sort(s)
+ str := "["
+ for i, elem := range s {
+ if i > 0 {
+ str += " "
+ }
+ str += fmt.Sprint(elem)
+ }
+ return str + "]"
+}
diff --git a/doc/progs/run b/doc/progs/run
index b60fdd7b3ed..7bff2ccf4f1 100755
--- a/doc/progs/run
+++ b/doc/progs/run
@@ -35,7 +35,9 @@ for i in \
sieve1.go \
server1.go \
strings.go \
+ eff_bytesize.go\
eff_qr.go \
+ eff_sequence.go\
; do
$GC $i
done
@@ -83,4 +85,7 @@ testitpipe sieve "sed 10q" "2 3 5 7 11 13 17 19 23 29"
$GC server.go
testit server1 "" ""
+testit eff_bytesize "" "1.00YB 9.09TB"
+testit eff_sequence "" "[-1 2 6 16 44]"
+
rm -f $O.out *.$O