[racket] Where to put the ellipsis?

I don't think you need 'dots' for what you want. 

Here is how you can organize your states: 
 n -- name of current thread 
 C -- control of current thread 
 E -- env of current thread 
 S -- global store 
 K -- continuation of current thread
 T -- thread pool : Name |-->f <C E K> (a finite map from names to states)

Then your beta-value reduction works as normal on the registers C through K and you can keep n and T opaque. 

Thread switches swap in/out the relevant C E Ks. 

No ellipses needed to single out the current thread. 



On Jul 15, 2013, at 12:40 PM, Monica Tomson <monica.tomson at gmail.com> wrote:

> 
> 
> 
> On Mon, Jul 15, 2013 at 6:48 AM, Matthias Felleisen <matthias at ccs.neu.edu> wrote:
> 
> Is this supposed to be a CESK machine state where you apply \x.M to V (actually V and the empty env, which is a highly unusual left-hand side)?
> 
> Yeah. the machine is a CESK machine, and the reduction rule is function application essentially. 
> 
> The change is that I want to model thread spawn and join, 
> which I think I can remodel the whole machine  in the way  that I can still "plug" the previous rules, except join and spawn, which i need to write new). and So, the model with thread is:
> 
>  (context (M ε κ))
>  (thread (tid context) )
>  (threads  (thread ...))
> 
> at the same time using a global store (Store) for simplicity, but really a state is a threads * store
> 
> and for the reduction with syntax error reported in the previous rule,
>  (Some mistakes in  the original post, so I copy-past it again below), 
> I try to use pattern matching the treads list, which tries to get the first thread entry from the list of threads, 
> 
> (-->
>     (((tid   (V ε (fn ((λ X M) ε_f) κ))) ...) S) ; tid, context
>      (((tid  (M  (update ε_f X σ_n) κ)) ...) S)
>      tcesk3
>      (where σ_n ,(fresh-σ))
>      (side-condition
>       (not (redex-match thread-cesk-iswim-plus X (term V ))) )  ;syntax: missing ellipsis with pattern variable in template in: V
>     (side-condition
>       (begin (store-update! (term σ_n) (term (V ε)) Store) #t)))
> 
> I am not sure the design or the whole things making sense or not, but just trying to do some exercise of using PLT-Redex...
> 
> Thanks,
> --Monica
> 
> 
> 
> On Jul 15, 2013, at 4:28 AM, Monica Tomson wrote:
> 
> > Hi,
> >
> > I have the following reduction rule, it keeps on throwing the compiling error:missing ellipsis with pattern variable in template in: V
> >
> > I am confused where to put the ellipsis?
> >
> >
> > (--> ;((V ε) S (fn ((λ X M) ε_f) κ))
> >         ;((M (update ε_f X σ_n)) S κ)
> >      ((tid  (V ε (fn ((λ X M) ε_f) κ))) ...) ; tid, context
> >      ((tid  (M  (update ε_f X σ_n) κ)) ...)
> >      tcesk3
> >      (where σ_n ,(fresh-σ))
> >      (side-condition
> >       (not (redex-match thread-cesk-iswim-plus X (term V ))) )  ; ERROR: syntax: missing ellipsis with pattern variable in template in: V
> >     (side-condition
> >       (begin (store-update! (term σ_n) (term (V ε)) Store) #t)))
> >
> > Thanks,
> >
> > --Shuying
> > ____________________
> >  Racket Users list:
> >  http://lists.racket-lang.org/users
> 
>