I see. A pattern like '~xs' is problematic as not every linear value can be freed.
On Wednesday, May 16, 2018 at 11:54:38 AM UTC-4, aditya siram wrote: > > I meant why couldn't you still a '~' on the 'xs' like > | (~Some_vt(~nested(~Some_vt(~list_vt_cons(x,~xs)))), ... => > > > > On Wednesday, May 16, 2018 at 8:59:48 AM UTC-5, gmhwxi wrote: >> >> The pattern ~list_vt_cons(x, xs) means the list constructor/node (that >> matches it) is freed; >> the head of the list is stored in 'x' and the tail in 'xs'. >> >> On Wed, May 16, 2018 at 9:56 AM, aditya siram <aditya...@gmail.com> >> wrote: >> >>> Awesome, thanks! I think my confusion was mostly that the error messages >>> complained about needing to retain a linear variable instead of consuming >>> it so I never tried to free them. Also why did 'xs' have to freed >>> explicitly with 'free(xs)' instead of using the '~' syntax in the pattern >>> match? >>> >>> >>> On Tuesday, May 15, 2018 at 9:35:14 PM UTC-5, gmhwxi wrote: >>>> >>>> Here is some code that typechecks: >>>> >>>> implement add_heads(a,b) = >>>> case (a,b) of >>>> | (~None_vt(),g) => g >>>> | (l, ~None_vt()) => l >>>> | (~Some_vt(~nested(~Some_vt(~list_vt_cons(x,xs)))), >>>> ~Some_vt(~nested(~Some_vt(~list_vt_cons(y,ys))))) => >>>> (free(xs); Some_vt(nested(Some_vt(list_vt_cons(x+y,ys))))) >>>> >>>> Some warnings are issued due to non-exhaustiveness of pattern matching >>>> involved. >>>> >>>> >>>> >>>> On Tue, May 15, 2018 at 10:27 PM, aditya siram <aditya...@gmail.com> >>>> wrote: >>>> >>>>> >>>>> #include "share/atspre_staload.hats" >>>>> >>>>> datavtype nested = nested of (Option_vt(List_vt(int))) >>>>> >>>>> extern fun add_heads( >>>>> a : Option_vt(nested), >>>>> b : Option_vt(nested) >>>>> ): Option_vt(nested) >>>>> >>>>> implement add_heads(a,b) = >>>>> case (a,b) of >>>>> | (~None_vt(),g) => g >>>>> | (l, ~None_vt()) => l >>>>> | (Some_vt(nested(Some_vt(list_vt_cons(x,_)))), >>>>> Some_vt(nested(Some_vt(list_vt_cons(y,ys))))) => >>>>> Some_vt(nested(Some_vt(list_vt_cons(x+y,ys)))) >>>>> >>>>> implement main0(argc,argv) = () >>>>> >>>>> >>>>> The above is a minimal non-compiling example from a larger program. I >>>>> even tried adding '@' to the pattern match with 'fold@' in the body but >>>>> it >>>>> didn't work. >>>>> >>>>> Thanks! >>>>> >>>>> On Tuesday, May 15, 2018 at 8:28:33 PM UTC-5, gmhwxi wrote: >>>>>> >>>>>> Oops. I am NOT so clear ... >>>>>> >>>>>> On Tue, May 15, 2018 at 9:27 PM, Hongwei Xi <gmh...@gmail.com> wrote: >>>>>> >>>>>>> I am so clear as to what you need precisely. >>>>>>> >>>>>>> Could you show me how to do it using pattern matching repeatly? >>>>>>> Then I may be able to do it using a nested pattern. >>>>>>> >>>>>>> Here is an example that may be useful: >>>>>>> >>>>>>> | ~Some_vt(~Some_vt(xs as list_vt_cons _)) => // using xs here >>>>>>> >>>>>>> The two Some_vt constructors are freed but list_vt_cons is not. >>>>>>> >>>>>>> On Tue, May 15, 2018 at 9:04 PM, aditya siram <aditya...@gmail.com> >>>>>>> wrote: >>>>>>> >>>>>>>> Hi all, >>>>>>>> I'm sure there's an easy answer to this but I'm not having much >>>>>>>> luck. How do I destructure into a view type that nested in another >>>>>>>> viewtype? For example, I'd to pattern match on something of type >>>>>>>> 'Option_vt(Option_vt(list_vt int))'. I'm not having much luck doing it >>>>>>>> in >>>>>>>> one fell swoop like: ' | Some_vt(Some_vt(list_vt_cons(x, xs))) => ...' >>>>>>>> especially when the linear proof of some inner value (like 'x') needs >>>>>>>> to be >>>>>>>> preserved. >>>>>>>> >>>>>>>> Thanks! >>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "ats-lang-users" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to ats-lang-user...@googlegroups.com. >>>>>>>> To post to this group, send email to ats-lan...@googlegroups.com. >>>>>>>> Visit this group at https://groups.google.com/group/ats-lang-users. >>>>>>>> To view this discussion on the web visit >>>>>>>> https://groups.google.com/d/msgid/ats-lang-users/e196b40c-7b12-45f1-abe6-4edb9d4bf3fd%40googlegroups.com >>>>>>>> >>>>>>>> <https://groups.google.com/d/msgid/ats-lang-users/e196b40c-7b12-45f1-abe6-4edb9d4bf3fd%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> >>>>>>> >>>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "ats-lang-users" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to ats-lang-user...@googlegroups.com. >>>>> To post to this group, send email to ats-lan...@googlegroups.com. >>>>> Visit this group at https://groups.google.com/group/ats-lang-users. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/ats-lang-users/46a9a11a-362c-426b-b479-5537a0a5aa8e%40googlegroups.com >>>>> >>>>> <https://groups.google.com/d/msgid/ats-lang-users/46a9a11a-362c-426b-b479-5537a0a5aa8e%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> >>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "ats-lang-users" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to ats-lang-user...@googlegroups.com. >>> To post to this group, send email to ats-lan...@googlegroups.com. >>> Visit this group at https://groups.google.com/group/ats-lang-users. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/ats-lang-users/5fd6e746-bc68-4a8c-92fe-5208be72fd69%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/ats-lang-users/5fd6e746-bc68-4a8c-92fe-5208be72fd69%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> >> -- You received this message because you are subscribed to the Google Groups "ats-lang-users" group. 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