From murdoch.duncan at gmail.com  Wed Feb 16 13:39:46 2011
From: murdoch.duncan at gmail.com (Duncan Murdoch)
Date: Wed, 16 Feb 2011 07:39:46 -0500
Subject: [Rd] Request: Suggestions for "good teaching" packages,
 esp. with C code
In-Reply-To: <4D5BC398.3050209@mx.uni-saarland.de>
References: <AANLkTikODppzk5=x7=TzVepH+aHuvaZUErf_0xQZ5ioX@mail.gmail.com>	<4D5AF4A8.50001@auckland.ac.nz>
	<4D5BC398.3050209@mx.uni-saarland.de>
Message-ID: <4D5BC592.6020900@gmail.com>

On 11-02-16 7:31 AM, Martin Becker wrote:
> On 15.02.2011 22:48, David Scott wrote:
>> On 16/02/2011 7:04 a.m., Paul Johnson wrote:
>>> ...
>>>
>>> 4. We don't want gratuitous use of "return" at the end of functions.
>>> Why do people still do that?
>>
>> Well I for one (and Jeff as well it seems) think it is good
>> programming practice. It makes explicit what is being returned
>> eliminating the possibility of mistakes and provides clarity for
>> anyone reading the code.
>>
>> David Scott
>>
>>
>
> AFAIR (but I am not sure, maybe some expert can comment on this), there
> is a difference between using return and not using return when R code is
> called from C-code via eval(). If my memory is correct, a return()
> statement (in the R code) would abort the C function (which is trying to
> evaluate the R code, e.g., the body of a function) as well, which is
> probably not intended. So, the use of return() in R code may be quite
> disadvantageous in certain situations.

As far as I know there is no such effect.  I suspect what you saw just 
triggered a bug in the C code that had stayed hidden before.

Duncan Murdoch



[Rd] Request: Suggestions for "good teaching" packages, esp. with C code
Duncan Murdoch