From: David Vallner <david@...>
Date: 2006-08-17T04:24:27+09:00
Subject: Re: goto function?

On Wed, 16 Aug 2006 13:55:01 +0200, Christian Neukirchen  
<chneukirchen@gmail.com> wrote:
> It is often said that continuations are as powerful as goto.
> But is there a way to jump *forward* with continuations, without
> rewriting the code to use additional methods?

As others said, continuations continue. You can jump backwards, because  
you know the whole context to jump into - it already existed.

To jump forward in code without explicitly setting up a context in which  
to run would either result in undefined behaviour, accepting some defaults  
for the context (all local / instance / other nonglobal variables are nil,  
for example), or the timespace continuum breaking. That might not apply if  
you were scripting a time machine, of course.

This is precisely why goto is considered harmful in the first place - to  
jump forward, you have to use only global context, or some other context  
that is defined to be shared when using such a construct. It would be  
interesting however if there was a concept of capture a (possible) future  
point of code execution without having to do explicit setup via a command  
object or something similar. I'll admit at this point that my savvy gets a  
little fuzzy around very high level programming theory - so I might  
actually be honking wrong in which case I'm all ears intrigued as to the  
workings of that construct.

David Vallner