[Rd] identical() fails to compare isS4(<S4 instance>) to TRUE

[Martin Morgan]

On 10/04/2012 05:56 PM, Martin Morgan wrote:
> On 10/04/2012 04:05 PM, Duncan Murdoch wrote:
>> On 12-10-04 5:50 PM, Martin Morgan wrote:
>>> On 10/04/2012 02:23 PM, Duncan Murdoch wrote:
>>>> On 12-10-04 4:57 PM, Martin Morgan wrote:
>>>>>
>>>>>    > setClass("A", "integer")
>>>>>    > isS4(new("A"))
>>>>> [1] TRUE
>>>>>    > identical(isS4(new("A")), TRUE)
>>>>> [1] FALSE
>>>>>
>>>>>    > sessionInfo()
>>>>> R Under development (unstable) (2012-10-04 r60876)
>>>>> Platform: x86_64-unknown-linux-gnu (64-bit)
>>>>>
>>>>> locale:
>>>>>     [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
>>>>>     [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
>>>>>     [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
>>>>>     [7] LC_PAPER=C                 LC_NAME=C
>>>>>     [9] LC_ADDRESS=C               LC_TELEPHONE=C
>>>>> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
>>>>>
>>>>> attached base packages:
>>>>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>>>>
>>>>
>>>> I can confirm this in R-devel, but it doesn't happen in R-patched.  In R-devel,
>>>> isS4 is returning a vector marked as LGLSXP, but containing the value 16, not
>>>> the usual 1 for TRUE.
>>>>
>>>>   > .Internal(inspect(isS4(new("A"))))
>>>> @4bfbed8 10 LGLSXP g0c1 [] (len=1, tl=0) 16
>>>>
>>>> I'm not going to have time to track this down and fix it.
>>>
>>> The bit is set at src/include/Rinternals.h:278
>>>
>>>    39103        jmc #define IS_S4_OBJECT(x) ((x)->sxpinfo.gp & S4_OBJECT_MASK)
>>>
>>> but it's identical that has changed; it looks as though there are other similar
>>> operations in that header and probably elsewhere.
>>
>> In R-patched, it returned the value 1 for TRUE, so I'm not sure identical() has
>> changed.
>
> R version 2.15.1 Patched (2012-09-24 r60798) has
>
>  > isS4
> function (object)
> .Call("R_isS4Object", object, PACKAGE = "base")
>
> with objects.c:1531
>
> SEXP R_isS4Object(SEXP object)
> {
>      /* wanted: return isS4(object) ? mkTrue() : mkFalse(); */
>      return IS_S4_OBJECT(object) ? mkTrue() : mkFalse(); ;
> }
>
> where R-devel has
>
>  > isS4
> function (object)  .Primitive("isS4")
>
> with coerce.c:1843
>
>      case 51:        /* isS4 */
>      LOGICAL(ans)[0] = IS_S4_OBJECT(CAR(args));
>      break;
>
> made in r60395

and fixed in r60877, thanks. Martin

>
> Martin
>
>>
>> Duncan Murdoch
>>
>>>
>>> Martin
>>>
>>>>
>>>> Duncan Murdoch
>>>
>>>
>>
>
>


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