[R] Construct a function with argments specified by an R expression

[Bert Gunter]

I disagree. I see "formals() <- "  as a way to compute on **functions**,
which are first class *objects* in R, as in any functional programming
language. This is not computing on the language  as I understand the term
-- substitute() and friends are, i.e. anything where eval() is needed to
get a result.

Cheers,
Bert


On Sun, Oct 26, 2025 at 7:36 AM Richard O'Keefe <raoknz using gmail.com> wrote:

> Can I just mention the quick-and-dirty way that will get the job done?
> Not as elegant as use the special features of the language *meant* for
> this kind of job,
> but suitable for a bear of very little brain.
>
> 1. Write a function that constructs the code you want as text, written
> to a file.
> 2. source() the file.'
>
> On Sat, 25 Oct 2025 at 15:23, Rolf Turner <rolfturner using posteo.net> wrote:
> >
> >
> > I want to build a function (say "buildFn") to *return* a function of the
> > form
> >
> >     foo(x,y,a1, ... an, b1, ..., bn)
> >
> > where the arguments ai and bi are given in the form of a list created
> > in R.  E.g. I'd like to be able to say
> >
> >      argnms <- c(paste0("a",1:3),paste0("b",1:3"))
> >      foo <- buildFn(argnms)
> >
> > with the resulting "foo" having arguments x, y, a1, a2, a3, b1, b2, b3.
> >
> > I thought I might be able to do this using "formals<-" but I cannot get
> > this to work.  i could provide more detail of what I've tried, but it's
> > probably not worth it.
> >
> > Can anyone steer me in the right direction?  Thanks.
> >
> > cheers,
> >
> > Rolf Turner
> >
> > --
> > Honorary Research Fellow
> > Department of Statistics
> > University of Auckland
> > Stats. Dep't. (secretaries) phone:
> >          +64-9-373-7599 ext. 89622
> > Home phone: +64-9-480-4619
> >
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> > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> https://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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