code review 813047: Add Error member to yyLexer type (yyError

Add Error member to yyLexer type (yyError
has no access to yylex)

[rog, 2010-04-19 16:07:08]

Hello ken2 (cc: golang-dev@googlegroups.com),

I'd like you to review this change.

[rog, 2010-04-26 21:40:21]

ping?

On 19 April 2010 17:07,  <rogpeppe@gmail.com> wrote:
> Reviewers: ken2,
>
> Message:
> Hello ken2 (cc: golang-dev@googlegroups.com),
>
> I'd like you to review this change.
>
>
> Description:
> Add Error member to yyLexer type (yyError
> has no access to yylex)
>
> Please review this at http://codereview.appspot.com/813047/show
>
> Affected files:
>  M src/cmd/goyacc/doc.go
>  M src/cmd/goyacc/goyacc.go
>  M src/cmd/goyacc/units.y
>
>
> Index: src/cmd/goyacc/doc.go
> ===================================================================
> --- a/src/cmd/goyacc/doc.go
> +++ b/src/cmd/goyacc/doc.go
> @@ -24,10 +24,12 @@
>
>        type yyLexer interface {
>                Lex(lval *yySymType) int
> +               Error()
>        }
>
>  Lex should return the token identifier, and place other token
>  information in lval (which replaces the usual yylval).
> +Error is equivalent to yyerror in the original yacc.
>
>  Code inside the parser may refer to the variable yylex
>  which holds the yyLexer passed to Parse.
> Index: src/cmd/goyacc/goyacc.go
> ===================================================================
> --- a/src/cmd/goyacc/goyacc.go
> +++ b/src/cmd/goyacc/goyacc.go
> @@ -3080,6 +3080,7 @@
>
>  type yyLexer interface {
>        Lex(lval *yySymType) int
> +       Error(s string)
>  }
>
>  const yyFlag = -1000
> @@ -3162,7 +3163,7 @@
>  yystack:
>        /* put a state and value onto the stack */
>        if yyDebug >= 4 {
> -               fmt.Printf("char %v in %v", yyTokname(yychar),
> yyStatname(yystate))
> +               fmt.Printf("char %v in %v\n", yyTokname(yychar),
> yyStatname(yystate))
>        }
>
>        yyp++
> @@ -3228,7 +3229,7 @@
>                /* error ... attempt to resume parsing */
>                switch Errflag {
>                case 0: /* brand new error */
> -                       yyError("syntax error")
> +                       yylex.Error("syntax error")
>                        Nerrs++
>                        if yyDebug >= 1 {
>                                fmt.Printf("%s", yyStatname(yystate))
> @@ -3273,7 +3274,7 @@
>
>        /* reduction by production yyn */
>        if yyDebug >= 2 {
> -               fmt.Printf("reduce %v in:\n\t%v", yyn, yyStatname(yystate))
> +               fmt.Printf("reduce %v in:\n\t%v\n", yyn,
> yyStatname(yystate))
>        }
>
>        yynt := yyn
> Index: src/cmd/goyacc/units.y
> ===================================================================
> --- a/src/cmd/goyacc/units.y
> +++ b/src/cmd/goyacc/units.y
> @@ -215,7 +215,7 @@
>
>  type UnitsLex int
>
> -func (l UnitsLex) Lex(yylval *yySymType) int {
> +func (_ UnitsLex) Lex(yylval *yySymType) int {
>        var c, i int
>
>        c = peekrune
> @@ -280,6 +280,10 @@
>        return VAL
>  }
>
> +func (_ UnitsLex) Error(s string) {
> +       Error("syntax error, last name: %v", sym)
> +}
> +
>  func main() {
>        var file string
>
> @@ -384,10 +388,6 @@
>        return false
>  }
>
> -func yyError(s string) {
> -       Error("syntax error, last name: %v", sym)
> -}
> -
>  func Error(s string, v ...interface{}) {
>        fmt.Printf("%v: %v\n\t", lineno, line)
>        fmt.Printf(s, v)
>
>
>

[ken3, 2010-04-30 01:10:31]

LGTM

put a string argument in the
declaration of Error method in doc.go.

sorry to hold this up so long

[rog, 2010-04-30 09:04:29]

On 30 April 2010 02:10,  <ken@google.com> wrote:
> put a string argument in the
> declaration of Error method in doc.go.

done.

> sorry to hold this up so long

no problem.

[rog, 2010-05-15 13:03:32]

*** Abandoned ***

[rog, 2010-05-17 12:03:16]

On 2010/05/15 13:03:32, rog wrote:
> *** Abandoned ***

i thought this had been submitted, but it hadn't.
any chance that it could be, please?

[ken3, 2010-05-17 19:23:56]

*** Submitted as http://code.google.com/p/go/source/detail?r=9f5547b196a3 ***

Add Error member to yyLexer type (yyError
has no access to yylex)

R=ken2, ken3
CC=golang-dev
http://codereview.appspot.com/813047

Committer: Ken Thompson <ken@golang.org>