[Rd] PROTECT and OCaml GC.

Guillaume Yziquel guillaume.yziquel at citycable.ch
Tue Dec 1 11:48:54 CET 2009

Guillaume Yziquel a écrit :
> One last thing, concerning the use of promises. If I do install, 
> findVar, without forcing the resulting promise, and then construct the 
> call, I get a failure:
>> # R.eval_langsxp (R.langsxp_of_list [(R.symbol "str"); (R.symbol 
>> "lm")] 2);;
>> Erreur dans function (object, ...)  :   function générique incorrecte 
>> dans 'UseMethod'
>> Exception: Failure "OCaml-R error in r_eval_sxp C stub.".
> If I force the promises:
>> # R.eval_langsxp (R.langsxp_of_list [(R.force (R.symbol "str")); 
>> (R.force (R.symbol "lm"))] 2);;
>> function (formula, data, subset, weights, na.action, method = "qr", 
>>     model = TRUE, x = FALSE, y = FALSE, qr = TRUE, singular.ok = TRUE, 
>>     contrasts = NULL, offset, ...)  - : R.sexp = <abstr>
> It works.
> So you may say that "I'm not constructing it right", I still believe 
> that describing precisely what kind of arguments is accepted by eval 
> would a good thing.

It seems that Matjaz Kukar had the same kind of issue that I have with 


I just remark two things from the resulting thread:

-1- He asks where to find a more precise documentation of the R API, 
which is also something I'd be looking for,

-2- He has been suggested to use findVar1, which doesn't seem to be part 
of the API.

Will be looking into findVar1, findFun, findVar, though I do not 
understand why this fails in my case. Please feel free to enlighten me.

All the best,

      Guillaume Yziquel

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