diff options
Diffstat (limited to 'src/pkg/big/rat.go')
| -rw-r--r-- | src/pkg/big/rat.go | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/src/pkg/big/rat.go b/src/pkg/big/rat.go index 2adf316e6..f11c27425 100644 --- a/src/pkg/big/rat.go +++ b/src/pkg/big/rat.go @@ -6,7 +6,11 @@ package big -import "strings" +import ( + "fmt" + "os" + "strings" +) // A Rat represents a quotient a/b of arbitrary precision. The zero value for // a Rat, 0/0, is not a legal Rat. @@ -209,6 +213,28 @@ func (z *Rat) Set(x *Rat) *Rat { } +func ratTok(ch int) bool { + return strings.IndexRune("+-/0123456789.eE", ch) >= 0 +} + + +// Scan is a support routine for fmt.Scanner. It accepts the formats +// 'e', 'E', 'f', 'F', 'g', 'G', and 'v'. All formats are equivalent. +func (z *Rat) Scan(s fmt.ScanState, ch int) os.Error { + tok, err := s.Token(true, ratTok) + if err != nil { + return err + } + if strings.IndexRune("efgEFGv", ch) < 0 { + return os.ErrorString("Rat.Scan: invalid verb") + } + if _, ok := z.SetString(string(tok)); !ok { + return os.ErrorString("Rat.Scan: invalid syntax") + } + return nil +} + + // SetString sets z to the value of s and returns z and a boolean indicating // success. s can be given as a fraction "a/b" or as a floating-point number // optionally followed by an exponent. If the operation failed, the value of z @@ -225,8 +251,8 @@ func (z *Rat) SetString(s string) (*Rat, bool) { return z, false } s = s[sep+1:] - var n int - if z.b, _, n = z.b.scan(s, 10); n != len(s) { + var err os.Error + if z.b, _, err = z.b.scan(strings.NewReader(s), 10); err != nil { return z, false } return z.norm(), true |