[racket] Where to put the ellipsis?

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
>
>
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