code review 6282043: text/template/parse: restore the goroutine

text/template/parse: restore the goroutine
To avoid goroutines during init, the nextItem function was a
clever workaround. Now that init goroutines are permitted,
restore the original, simpler design.

[r, 2012-06-02 00:51:30]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[bradfitz, 2012-06-02 01:19:00]

LGTM

On Fri, Jun 1, 2012 at 5:51 PM, <r@golang.org> wrote:

> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go/
>
>
> Description:
> text/template/parse: restore the goroutine
> To avoid goroutines during init, the nextItem function was a
> clever workaround. Now that init goroutines are permitted,
> restore the original, simpler design.
>
> Please review this at
http://codereview.appspot.com/**6282043/<http://codereview.appspot.com/6282043/>
>
> Affected files:
>  M src/pkg/text/template/parse/**lex.go
>
>
> Index: src/pkg/text/template/parse/**lex.go
> ==============================**==============================**=======
> --- a/src/pkg/text/template/parse/**lex.go
> +++ b/src/pkg/text/template/parse/**lex.go
> @@ -195,15 +195,7 @@
>
>  // nextItem returns the next item from the input.
>  func (l *lexer) nextItem() item {
> -       for {
> -               select {
> -               case item := <-l.items:
> -                       return item
> -               default:
> -                       l.state = l.state(l)
> -               }
> -       }
> -       panic("not reached")
> +       return <-l.items
>  }
>
>  // lex creates a new scanner for the input string.
> @@ -219,12 +211,19 @@
>                input:      input,
>                leftDelim:  left,
>                rightDelim: right,
> -               state:      lexText,
> -               items:      make(chan item, 2), // Two items of buffering
> is sufficient for all state functions
> +               items:      make(chan item),
>        }
> +       go l.run()
>        return l
>  }
>
> +// run runs the state machine for the lexer.
> +func (l *lexer) run() {
> +       for l.state = lexText; l.state != nil; {
> +               l.state = l.state(l)
> +       }
> +}
> +
>  // state functions
>
>  const (
> @@ -391,7 +390,7 @@
>  }
>
>  // lexChar scans a character constant. The initial quote is already
> -// scanned.  Syntax checking is done by the parse.
> +// scanned.  Syntax checking is done by the parser.
>  func lexChar(l *lexer) stateFn {
>  Loop:
>        for {
>
>
>

[r, 2012-06-02 01:34:25]

*** Submitted as http://code.google.com/p/go/source/detail?r=0b9ae2971811 ***

text/template/parse: restore the goroutine
To avoid goroutines during init, the nextItem function was a
clever workaround. Now that init goroutines are permitted,
restore the original, simpler design.

R=golang-dev, bradfitz
CC=golang-dev
http://codereview.appspot.com/6282043