On 6/20/20 9:00 AM, Duncan Murdoch wrote:
How about
g <- function(x, y = x) {
f(x, y)
}
g(x = 3)
or even
yEqualsX <- function(f) function(x, y = x) f(x, y)
yEqualsX(f)(x = 3)
These are a lot like currying, but aren't currying, so they may be
acceptable to you. Personally I'd choose the first one.
Duncan Murdoch
Thank you Duncan; I should have been more explicit that I was also
trying to avoid defining any new functions, but yes, it's hard to argue
with the wrapper approach as a longstanding best practice.
Basically I'm wondering if it would be theoretically possible to
construct a function "g" (possibly it would have to be
primitive/internal) such that
f(x = 3, y = g(expr))
would evaluate expr in the evaluation environment of f? After rereading
section 4.3.3 of the R Language Definition, it's clear that supplied
arguments are evaluated in the calling environment; though trickery in
f()'s body may be used to evaluate elsewhere, such options seem limited
from within the argument list itself.
Ben
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