From @zwj|08 @end|ng |rom gm@||@com  Tue Sep  3 20:49:56 2019
From: @zwj|08 @end|ng |rom gm@||@com (Wang Jiefei)
Date: Tue, 3 Sep 2019 14:49:56 -0400
Subject: [Rd] [ALTREP] What is the meaning of the return value of Is_sorted
 and No_NA function?
Message-ID: <CAGiFhPO-CrCHww-dZV_bDaD20DEkD583SRkhRCGsEvDQCtgHJQ-6992@mail.gmail.com>

Hi,



I would like to figure out the meaning of the return value of these two
functions. Here are the default definitions I find from R source code:



static int altreal_Is_sorted_default(SEXP x) { return UNKNOWN_SORTEDNESS; }

static int altreal_No_NA_default(SEXP x) { return 0; }

I guess the macro *UNKNOWN_SORTEDNESS *in *Is_sorted* and 0 in *No_NA
*simply means
unknown sorted/NA status of the vector, so R will loop over the vector and
find the answer. However, what should we return in these functions to
indicate whether the vector has been sorted/ contains NA? My initial guess
is 0/1 but since *NA_NA *uses 0 as its default value so it will be
ambiguous. Are there any macros to define yes/no return values for these
functions? I would appreciate any thought here.



Best,

Jiefei

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[Rd] [ALTREP] What is the meaning of the return value of Is_sorted and No_NA function?
Wang Jiefei