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Message-ID: <d3b34b25-c031-6d5d-6080-b1e3b4e92513@umu.se>
Date: 2022-03-30T10:43:52Z
From: Göran Broström
Subject: Where is list.names?
In-Reply-To: <20220330124851.28027df6@arachnoid>

On 2022-03-30 11:48, Ivan Krylov wrote:
> ? Wed, 30 Mar 2022 11:27:05 +0200 G?ran Brostr?m
> <goran.brostrom at umu.se> ?????:
> 
>> I can guess what 'list.names' is (from the documentation), but
>> where and how is it defined?
> 
> Interesting! It's defined first thing inside the function, so by the 
> time the function tries to use the argument, list.names exists and
> can be called, but for all other purposes, it's not there.

Thanks for that (also thanks to Eric)!

> 
> What if you don't set a default value for dnn in your wrapper or

That works, if I check for missing argument:


table <- function(...,
                   useNA = "ifany",
                   exclude = if (useNA == "no") c(NA, NaN),
                   dnn,
                   deparse.level = 1){
     if (missing(dnn)){
         base::table(...,
                     exclude = exclude,
                     useNA = useNA,
                     deparse.level = deparse.level)
     }else{
         base::table(...,
                     useNA = useNA,
                     exclude = exclude,
                     dnn = dnn,
                     deparse.level = deparse.level)
     }
}

Is this the final word?

G?ran

> even mention dnn as a formal argument in your wrapper? In many cases,
> it's possible to forward missing arguments to functions and have them
> do the right thing. The only other solution I can think of is
> non-standard evaluation.
>