search for: vec_c

...eful to get comments from a wide audience, so I?m reaching out to R-devel to get your thoughts. There is quite a lot already in the readme (<https://github.com/r-lib/vctrs#vctrs>), so here I?ll try to motivate vctrs as succinctly as possible by comparing `base::c()` to its equivalent `vctrs::vec_c()`. I think the drawbacks of `c()` are well known, but to refresh your memory, I?ve highlighted a few at <https://github.com/r-lib/vctrs#compared-to-base-r>. I think they arise because of two main challenges: `c()` has to both combine vectors *and* strip attributes, and it only dispatches on...

...ide audience, so I?m reaching out to R-devel to get > your thoughts. > > There is quite a lot already in the readme > (<https://github.com/r-lib/vctrs#vctrs>), so here I?ll try to motivate > vctrs as succinctly as possible by comparing `base::c()` to its > equivalent `vctrs::vec_c()`. I think the drawbacks of `c()` are well > known, but to refresh your memory, I?ve highlighted a few at > <https://github.com/r-lib/vctrs#compared-to-base-r>. I think they arise > because of two main challenges: `c()` has to both combine vectors *and* > strip attributes, and it...

...ching out to R-devel to get >> your thoughts. >> >> There is quite a lot already in the readme >> (<https://github.com/r-lib/vctrs#vctrs>), so here I?ll try to motivate >> vctrs as succinctly as possible by comparing `base::c()` to its >> equivalent `vctrs::vec_c()`. I think the drawbacks of `c()` are well >> known, but to refresh your memory, I?ve highlighted a few at >> <https://github.com/r-lib/vctrs#compared-to-base-r>. I think they arise >> because of two main challenges: `c()` has to both combine vectors *and* >> strip at...

...y it refers to a set of rules (either statically enforced > by the compiler or dynamically enforced by the runtime) that ensure > that some particular category of errors can be caught by the > language. > > There is none of that here. I think there's a bit of that flavour here: vec_c(factor("a"), Sys.Date()) #> Error: No common type for factor and date This isn't a type system imposed by the language, but I don't think that's a reason not to call it a type system. That said, I agree that calling it a type system is currently overselling it, and I have...

>>>>> Hadley Wickham >>>>> on Wed, 8 Aug 2018 09:34:42 -0500 writes: >>>> Method dispatch for `vec_c()` is quite simple because >>>> associativity and commutativity mean that we can >>>> determine the output type only by considering a pair of >>>> inputs at a time. To this end, vctrs provides >>>> `vec_type2()` which takes two inputs...

...classes (and indeed it's implemented using S3), the coercion/casting relationship do not strictly follow the subclass/superclass relationships. A good motivating example is now ordered vs factor - I don't think you can say that ordered or factor have greater resolution than the other so: vec_c(factor("a"), ordered("a")) #> Error: No common type for factor and ordered This is not what you'd expect from an _object_ system since ordered is a subclass of factor. Hadley -- http://hadley.nz

>>> Method dispatch for `vec_c()` is quite simple because associativity and >>> commutativity mean that we can determine the output type only by >>> considering a pair of inputs at a time. To this end, vctrs provides >>> `vec_type2()` which takes two inputs and returns their common type >>> (r...

...tion, in practice, does that. Best, ~G On Wed, Aug 8, 2018 at 8:54 AM, Martin Maechler <maechler at stat.math.ethz.ch> wrote: > >>>>> Hadley Wickham > >>>>> on Wed, 8 Aug 2018 09:34:42 -0500 writes: > > >>>> Method dispatch for `vec_c()` is quite simple because > >>>> associativity and commutativity mean that we can > >>>> determine the output type only by considering a pair of > >>>> inputs at a time. To this end, vctrs provides > >>>> `vec_type2()` whi...

> > As Gabe mentioned (and you've explained about) the term "type" > > is really confusing here. As you know, the R internals are all > > about SEXPs, TYPEOF(), etc, and that's what the R level > > typeof(.) also returns. As you want to use something slightly > > different, it should be different naming, ideally something not > > existing yet

Hadley, Responses inline. On Wed, Aug 8, 2018 at 7:34 AM, Hadley Wickham <h.wickham at gmail.com> wrote: > >>> Method dispatch for `vec_c()` is quite simple because associativity and > >>> commutativity mean that we can determine the output type only by > >>> considering a pair of inputs at a time. To this end, vctrs provides > >>> `vec_type2()` which takes two inputs and returns their common type...

...-stable functions makes code easier to reason about and hence more likely to be bug free. You can read more about size- and type-stability at <https://vctrs.r-lib.org/articles/stability.html>. This vignette includes a detailed analysis of `c()` and a type- and size-stable alternative called `vec_c()`. ## New vector types Finally, vctrs provides `new_vctr()` and `new_rcrd()` to make it easier to define new classes, following the conventions that I?ve found helpful, including writing a constructor function that enforces the types of the underlying vector and its attributes (more details at &...

...G > > On Wed, Aug 8, 2018 at 8:54 AM, Martin Maechler <maechler at stat.math.ethz.ch> > wrote: > > > >>>>> Hadley Wickham > > >>>>> on Wed, 8 Aug 2018 09:34:42 -0500 writes: > > > > >>>> Method dispatch for `vec_c()` is quite simple because > > >>>> associativity and commutativity mean that we can > > >>>> determine the output type only by considering a pair of > > >>>> inputs at a time. To this end, vctrs provides > > >>>&g...