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Groups > comp.lang.javascript > #9677

Re: Simulate goto

Followups directed to: comp.lang.javascript

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Tom de Neef wrote:

> "Archos" <raul.san@sent.com> schreef […]
>> I'm trying to simulate the goto statement but I get an error
>>
>> ===
>> function testGoto() {
>> var isFirst = true;
>>
>> skipPoint:
>> alert("Using goto\n");
>>
>> if (isFirst) {
>> isFirst = false;
>> continue skipPoint;
>> alert("This part is skipped");
>> }
>> }
>> ===
>>
>> SyntaxError: label not found
>> continue skipPoint;
> 
> The error may have more to do with 'continue' than with the label.
> Check where you can use a continue statement - I think it is restricted to
> for- and while- loops.

You are mistaken.  The `continue' statement, like the Labelled Statement is 
just another /Statement/, and it can be located anywhere in a /Program/:

,-[ES 5.1]
| 
| 14 Program
| 
| Syntax
| 
| Program :
|   SourceElements_opt
| 
| SourceElements :
|   SourceElement
|   SourceElements SourceElement
| 
| SourceElement :
|   Statement
|   FunctionDeclaration

,-[ibid.]
| 
| 12 Statements
| 
| Syntax
| 
| Statement :
|   Block
|   VariableStatement
|   EmptyStatement
|   ExpressionStatement
|   IfStatement
|   IterationStatement
|   ContinueStatement
|   […]
|   LabelledStatement
|   […]
| 
| 12.3 Empty Statement
| 
| Syntax
|   EmptyStatement :
|     ;
| 
| […]
| 12.7 The continue Statement
| 
| Syntax
| 
| ContinueStatement :
|   continue ;
|   continue [no LineTerminator here] Identifier;
| 
| […]
| 12.12 Labelled Statements
| 
| Syntax
| 
| LabelledStatement :
|   Identifier : Statement

`skipPoint' is an /Identifier/ and – through Automatic Semicolon Insertion 
(ASI) – an /EmptyStatement/ is a /Statement/.  One could try placing the 
/ExpressionStatement/ – alert(…) – at the same line as the label, but that 
should not be necessary in a conforming implementation (which implementation 
has been tested with?).

That said, it is certainly not a good idea to "simulate the goto statement".

Please do not post attribution novels: <http://insideoe.com/>


PointedEars
-- 
> If you get a bunch of authors […] that state the same "best practices"
> in any programming language, then you can bet who is wrong or right...
Not with javascript. Nonsense propagates like wildfire in this field.
  -- Richard Cornford, comp.lang.javascript, 2011-11-14

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Thread

Simulate goto Archos <raul.san@sent.com> - 2011-12-27 01:19 -0800
  Re: Simulate goto Archos <raul.san@sent.com> - 2011-12-27 01:50 -0800
    Re: Simulate goto Archos <raul.san@sent.com> - 2011-12-27 02:09 -0800
      Re: Simulate goto Erwin Moller <Since_humans_read_this_I_am_spammed_too_much@spamyourself.com> - 2011-12-27 11:31 +0100
  Re: Simulate goto "Tom de Neef" <tdeneef@qolor.nl> - 2011-12-27 12:12 +0100
    Re: Simulate goto Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-12-27 18:27 +0100
      Re: Simulate goto John G Harris <john@nospam.demon.co.uk> - 2011-12-28 16:56 +0000
        Re: Simulate goto Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-12-28 19:10 +0100
          Re: Simulate goto Jake Jarvis <pig_in_shoes@yahoo.com> - 2011-12-28 23:18 +0100
            Re: Simulate goto Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-12-29 12:18 +0100
              Re: Simulate goto John G Harris <john@nospam.demon.co.uk> - 2011-12-29 16:31 +0000
                Re: Simulate goto Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-12-29 17:47 +0100
                Re: Simulate goto John G Harris <john@nospam.demon.co.uk> - 2011-12-30 11:04 +0000
                Re: Simulate goto Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-12-30 16:10 +0100
  Re: Simulate goto John G Harris <john@nospam.demon.co.uk> - 2011-12-27 14:41 +0000
  Re: Simulate goto Denis McMahon <denismfmcmahon@gmail.com> - 2011-12-27 15:32 +0000
    Re: Simulate goto Gene Wirchenko <genew@ocis.net> - 2011-12-27 10:12 -0800
      Re: Simulate goto "Evertjan." <exjxw.hannivoort@interxnl.net> - 2011-12-27 19:55 +0000
        Re: Simulate goto Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2011-12-27 21:49 +0100
          Re: Simulate goto Denis McMahon <denismfmcmahon@gmail.com> - 2011-12-27 23:07 +0000
          Re: Simulate goto John G Harris <john@nospam.demon.co.uk> - 2011-12-28 16:28 +0000
            Re: Simulate goto Nomen Nescio <nobody@dizum.com> - 2011-12-28 22:33 +0100
        Re: Simulate goto Gene Wirchenko <genew@ocis.net> - 2011-12-27 13:19 -0800
          Re: Simulate goto "Evertjan." <exjxw.hannivoort@interxnl.net> - 2011-12-27 22:02 +0000
            Re: Simulate goto Tim Streater <timstreater@greenbee.net> - 2011-12-27 22:18 +0000
              Re: Simulate goto Mike Duffy <Use_guestbook_page@website.in.sig> - 2011-12-28 00:23 +0000
                Re: Simulate goto John G Harris <john@nospam.demon.co.uk> - 2011-12-28 16:37 +0000
                Re: Simulate goto Tim Streater <timstreater@greenbee.net> - 2011-12-28 17:44 +0000
                Re: Simulate goto Mike Duffy <Use_guestbook_page@website.in.sig> - 2011-12-29 01:16 +0000
                Re: Simulate goto Gene Wirchenko <genew@ocis.net> - 2011-12-28 17:34 -0800
                Re: Simulate goto "Evertjan." <exjxw.hannivoort@interxnl.net> - 2011-12-29 08:27 +0000
                Re: Simulate goto Dr J R Stockton <reply1152@merlyn.demon.co.uk> - 2011-12-30 20:54 +0000
                Re: Simulate goto Tim Streater <timstreater@greenbee.net> - 2011-12-31 11:55 +0000
            Re: Simulate goto Gene Wirchenko <genew@ocis.net> - 2011-12-27 14:50 -0800

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