code review 179088: Parse expressions as opposed to statements for gofmt re...

- Parse expressions as opposed to statements for gofmt rewrite patterns.
Allows stand-alone types (e.g. []int as patterns) and doesn't require
a semicolon at the end (which are now mandatory terminators).

- Fix a matcher bug.

[gri, 2009-12-17 00:21:00]

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

I'd like you to review the following change.

[rsc, 2009-12-17 00:47:15]

LGTM

should be a change in another file too?

On Wed, Dec 16, 2009 at 16:21,  <gri@golang.org> wrote:
> Reviewers: rsc,
>
> Message:
> Hello rsc (cc: golang-dev@googlegroups.com),
>
> I'd like you to review the following change.
>
>
> Description:
> Parse expressions as opposed to statements for gofmt rewrite patterns.
> Allows stand-alone types (e.g. []int as patterns) and doesn't require
> a semicolon at the end (which are now mandatory terminators).
>
> Please review this at http://codereview.appspot.com/179088
>
> Affected files:
>  M src/cmd/gofmt/rewrite.go
>
>
> Index: src/cmd/gofmt/rewrite.go
> ===================================================================
> --- a/src/cmd/gofmt/rewrite.go
> +++ b/src/cmd/gofmt/rewrite.go
> @@ -37,21 +37,12 @@
>  // but there are problems with preserving formatting and also
>  // with what a wildcard for a statement looks like.
>  func parseExpr(s string, what string) ast.Expr {
> -       stmts, err := parser.ParseStmtList("input", s)
> +       x, err := parser.ParseExpr("input", s)
>        if err != nil {
>                fmt.Fprintf(os.Stderr, "parsing %s %s: %s\n", what, s, err)
>                os.Exit(2)
>        }
> -       if len(stmts) != 1 {
> -               fmt.Fprintf(os.Stderr, "%s must be single expression\n",
> what)
> -               os.Exit(2)
> -       }
> -       x, ok := stmts[0].(*ast.ExprStmt)
> -       if !ok {
> -               fmt.Fprintf(os.Stderr, "%s must be single expression\n",
> what)
> -               os.Exit(2)
> -       }
> -       return x.X
> +       return x
>  }
>
>
>
>
>

[gri, 2009-12-17 00:54:04]

*** Submitted as http://code.google.com/p/go/source/detail?r=6a07fd3abfbc ***

- Parse expressions as opposed to statements for gofmt rewrite patterns.
Allows stand-alone types (e.g. []int as patterns) and doesn't require
a semicolon at the end (which are now mandatory terminators).

- Fix a matcher bug.

R=rsc
CC=golang-dev
http://codereview.appspot.com/179088