code review 4248076: fmt: heaven forfend we export EOF = -1

fmt: heaven forfend we export EOF = -1

[r, 2011-03-10 00:47:20]

Hello adg (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg/

[adg, 2011-03-10 00:51:58]

LGTM

and I learned a new word! ("forfend")

On 10 March 2011 11:47,  <r@golang.org> wrote:
> Reviewers: adg,
>
> Message:
> Hello adg (cc: golang-dev@googlegroups.com),
>
> I'd like you to review this change to
> https://go.googlecode.com/hg/
>
>
> Description:
> fmt: heaven forfend we export EOF = -1
>
> Please review this at http://codereview.appspot.com/4248076/
>
> Affected files:
>  M src/pkg/fmt/scan.go
>
>
> Index: src/pkg/fmt/scan.go
> ===================================================================
> --- a/src/pkg/fmt/scan.go
> +++ b/src/pkg/fmt/scan.go
> @@ -139,7 +139,7 @@
>        err os.Error
>  }
>
> -const EOF = -1
> +const eof = -1
>
>  // ss is the internal implementation of ScanState.
>  type ss struct {
> @@ -207,7 +207,7 @@
>        rune, _, err := s.ReadRune()
>        if err != nil {
>                if err == os.EOF {
> -                       return EOF
> +                       return eof
>                }
>                s.error(err)
>        }
> @@ -219,7 +219,7 @@
>  // syntax error.
>  func (s *ss) mustReadRune() (rune int) {
>        rune = s.getRune()
> -       if rune == EOF {
> +       if rune == eof {
>                s.error(io.ErrUnexpectedEOF)
>        }
>        return
> @@ -378,7 +378,7 @@
>  func (s *ss) skipSpace(stopAtNewline bool) {
>        for {
>                rune := s.getRune()
> -               if rune == EOF {
> +               if rune == eof {
>                        return
>                }
>                if rune == '\n' {
> @@ -409,7 +409,7 @@
>        // read until white space or newline
>        for {
>                rune := s.getRune()
> -               if rune == EOF {
> +               if rune == eof {
>                        break
>                }
>                if !f(rune) {
> @@ -433,7 +433,7 @@
>  // If accept is true, it puts the character into the input token.
>  func (s *ss) consume(ok string, accept bool) bool {
>        rune := s.getRune()
> -       if rune == EOF {
> +       if rune == eof {
>                return false
>        }
>        if strings.IndexRune(ok, rune) >= 0 {
> @@ -442,7 +442,7 @@
>                }
>                return true
>        }
> -       if rune != EOF && accept {
> +       if rune != eof && accept {
>                s.UnreadRune()
>        }
>        return false
> @@ -451,7 +451,7 @@
>  // peek reports whether the next character is in the ok string, without
> consuming it.
>  func (s *ss) peek(ok string) bool {
>        rune := s.getRune()
> -       if rune != EOF {
> +       if rune != eof {
>                s.UnreadRune()
>        }
>        return strings.IndexRune(ok, rune) >= 0
> @@ -814,7 +814,7 @@
>  // There must be either two hexadecimal digits or a space character in the
> input.
>  func (s *ss) hexByte() (b byte, ok bool) {
>        rune1 := s.getRune()
> -       if rune1 == EOF {
> +       if rune1 == eof {
>                return
>        }
>        if unicode.IsSpace(rune1) {
> @@ -970,7 +970,7 @@
>        if !s.nlIsSpace {
>                for {
>                        rune := s.getRune()
> -                       if rune == '\n' || rune == EOF {
> +                       if rune == '\n' || rune == eof {
>                                break
>                        }
>                        if !unicode.IsSpace(rune) {
> @@ -1010,7 +1010,7 @@
>                        // There was space in the format, so there should be
> space (EOF)
>                        // in the input.
>                        inputc := s.getRune()
> -                       if inputc == EOF {
> +                       if inputc == eof {
>                                return
>                        }
>                        if !unicode.IsSpace(inputc) {
>
>
>

[r, 2011-03-10 00:53:35]

*** Submitted as http://code.google.com/p/go/source/detail?r=a3f18cf885c9 ***

fmt: heaven forfend we export EOF = -1

R=adg
CC=golang-dev
http://codereview.appspot.com/4248076

[rsc1, 2011-03-10 01:19:49]

what about ScanState.GetRune?


type ScanState interface {
    // GetRune reads the next rune (Unicode code point) from the input.
    // If invoked during Scanln, Fscanln, or Sscanln, GetRune() will
    // return EOF after returning the first '\n'.
    GetRune() (rune int, err os.Error)
    // UngetRune causes the next call to GetRune to return the same rune.
    UngetRune()
    // Width returns the value of the width option and whether it has been set.
    // The unit is Unicode code points.
    Width() (wid int, ok bool)
    // Token returns the next space-delimited token from the input. If
    // a width has been specified, the returned token will be no longer
    // than the width.
    Token() (token string, err os.Error)
}
ScanState represents the scanner state passed to custom scanners.
Scanners may do rune-at-a-time scanning or ask the ScanState
to discover the next space-delimited token.

[r2, 2011-03-10 01:21:13]

On Mar 9, 2011, at 5:17 PM, Russ Cox wrote:

> what about ScanState.GetRune?
> 
> 
> type ScanState interface {
>    // GetRune reads the next rune (Unicode code point) from the input.
>    // If invoked during Scanln, Fscanln, or Sscanln, GetRune() will
>    // return EOF after returning the first '\n'.
>    GetRune() (rune int, err os.Error)
>    // UngetRune causes the next call to GetRune to return the same rune.
>    UngetRune()
>    // Width returns the value of the width option and whether it has been set.
>    // The unit is Unicode code points.
>    Width() (wid int, ok bool)
>    // Token returns the next space-delimited token from the input. If
>    // a width has been specified, the returned token will be no longer
>    // than the width.
>    Token() (token string, err os.Error)
> }
> ScanState represents the scanner state passed to custom scanners.
> Scanners may do rune-at-a-time scanning or ask the ScanState
> to discover the next space-delimited token.

it's been called ReadRune for quite a while, and EOF is an error, not the
returned rune.

-rob