Message:
Hello [email protected],
I'd like you to review this change to
https://code.google.com/p/go/
Description:
fmt: fix documentation glitch in index expressions in Printf
Also clean up the code a bit.
Please review this at https://codereview.appspot.com/9761043/
Affected files:
M src/pkg/fmt/doc.go
M src/pkg/fmt/fmt_test.go
M src/pkg/fmt/print.go
Index: src/pkg/fmt/doc.go
===================================================================
--- a/src/pkg/fmt/doc.go
+++ b/src/pkg/fmt/doc.go
@@ -124,9 +124,9 @@
formatting verb to format successive arguments passed in the call.
However, the notation [n] immediately before the verb indicates that the
nth one-indexed argument is to be formatted instead. The same notation
- before a '*' for a width or precision selects the argument index holding
- the value. After processing a bracketed expression [n], arguments n+1,
- n+2, etc. will be processed unless otherwise directed.
+ before a '*' for a width or a '.*' for precision selects the argument
+ index holding the value. After processing a bracketed expression [n],
+ arguments n+1, n+2, etc. will be processed unless otherwise directed.
For example,
fmt.Sprintf("%[2]d %[1]d\n", 11, 22)
Index: src/pkg/fmt/fmt_test.go
===================================================================
--- a/src/pkg/fmt/fmt_test.go
+++ b/src/pkg/fmt/fmt_test.go
@@ -553,6 +553,7 @@
{"%6.2f", SE{12.0}, " 12.00"},
{"%[3]*[2].*[1]f", SE{12.0, 2, 6}, " 12.00"},
{"%[1]*[2].*[3]f", SE{6, 2, 12.0}, " 12.00"},
+ {"%[2].*[3]f", SE{6, 3, 12.0}, "12.000"},
// An actual use! Print the same arguments twice.
{"%d %d %d %#[1]o %#o %#o", SE{11, 12, 13}, "11 12 13 013 014 015"},
Index: src/pkg/fmt/print.go
===================================================================
--- a/src/pkg/fmt/print.go
+++ b/src/pkg/fmt/print.go
@@ -1021,11 +1021,11 @@
}
// intFromArg gets the argNumth element of a. On return, isInt reports
whether the argument has type int.
-func intFromArg(a []interface{}, end, i, argNum int) (num int, isInt bool,
newi, newArgNum int) {
- newi, newArgNum = end, argNum
- if i < end && argNum < len(a) {
+func intFromArg(a []interface{}, argNum int) (num int, isInt bool,
newArgNum int) {
+ newArgNum = argNum
+ if argNum < len(a) {
num, isInt = a[argNum].(int)
- newi, newArgNum = i+1, argNum+1
+ newArgNum = argNum + 1
}
return
}
@@ -1112,7 +1112,8 @@
// Do we have width?
if i < end && format[i] == '*' {
- p.fmt.wid, p.fmt.widPresent, i, argNum = intFromArg(a, end, i, argNum)
+ i++
+ p.fmt.wid, p.fmt.widPresent, argNum = intFromArg(a, argNum)
if !p.fmt.widPresent {
p.buf.Write(badWidthBytes)
}
@@ -1123,14 +1124,16 @@
// Do we have precision?
if i+1 < end && format[i] == '.' {
- if format[i+1] == '*' {
- p.fmt.prec, p.fmt.precPresent, i, argNum = intFromArg(a, end, i+1,
argNum)
+ i++
+ if format[i] == '*' {
+ i++
+ p.fmt.prec, p.fmt.precPresent, argNum = intFromArg(a, argNum)
if !p.fmt.precPresent {
p.buf.Write(badPrecBytes)
}
argNum, i = p.argNumber(argNum, format, i, len(a)) // We consumed [];
another can follow here.
} else {
- p.fmt.prec, p.fmt.precPresent, i = parsenum(format, i+1, end)
+ p.fmt.prec, p.fmt.precPresent, i = parsenum(format, i, end)
if !p.fmt.precPresent {
p.fmt.prec = 0
p.fmt.precPresent = true
--
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