From peter.meilstrup at gmail.com  Fri Oct  5 00:53:12 2012
From: peter.meilstrup at gmail.com (Peter Meilstrup)
Date: Thu, 4 Oct 2012 15:53:12 -0700
Subject: [Rd] How to build a list with missing values? What is missing,
	anyway?
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On Wed, Oct 3, 2012 at 11:21 PM, Josh O'Brien <joshmobrien at gmail.com> wrote:
>
>>Say I have argnames <- c("a", "b", "c").
> >From that I want to construct the equivalent of alist(a=, b=, c=).
>
> Here's a one liner that'll do that for you:
>
> argnames <- letters[1:3]
> setNames(rep(list(bquote()), length(argnames)), argnames)

Thanks.

Just so I have my mental model correct, I'm gathering that missing/``
is a symbol that the interpreter has a special rule for -- evaluating
it raises an error, as opposed to objects that evaluate to themselves
or variable names that evaluate to objects.

Does the same sort of thing explain the behavior of `...`? When the
interpreter comes across `...` in the arguments during evaluation of a
call, it trips a special argument-interpolating behavior?

Peter



[Rd] How to build a list with missing values? What is missing, anyway?
Peter Meilstrup