R devel - Sep 2010 - warning or error upon type/storage mode coercion?

Hi,

I'm aware that the language definition states "R objects are often 
coerced to different types during computations". Two questions:

1. Is it possible to configure the R environment so that, for example, 
coercion from (say) numeric to integer will throw a warning or an error? 
I realize that in the base R code alone, there are thousands of calls to 
as.integer() which would trigger such an event, so this would not be a 
very practical configuration...

2. So, assuming the answer to (1) is a resounding "no", does anyone
care
to state an opinion regarding the philosophical or historical rationale 
for why this is the case in R/S, whereas certain other interpreted 
languages offer the option to perform strict type checking? Basically, 
I'm trying to explain to someone from a perl background why the 
(apparent) lack of a "use strict; use warnings;" equivalent is not a 
hindrance to writing bullet-proof R code.

Thanks,
Ben

On Tue, Sep 14, 2010 at 6:23 PM, Benjamin Tyner <btyner at gmail.com>
wrote:
> Hi,
>
> I'm aware that the language definition states "R objects are often
coerced
> to different types during computations". Two questions:
>
> 1. Is it possible to configure the R environment so that, for example,
> coercion from (say) numeric to integer will throw a warning or an error? I
> realize that in the base R code alone, there are thousands of calls to
> as.integer() which would trigger such an event, so this would not be a very
> practical configuration...
>
> 2. So, assuming the answer to (1) is a resounding "no", does
anyone care to
> state an opinion regarding the philosophical or historical rationale for
why
> this is the case in R/S, whereas certain other interpreted languages offer
> the option to perform strict type checking? Basically, I'm trying to
explain
> to someone from a perl background why the (apparent) lack of a "use
strict;
> use warnings;" equivalent is not a hindrance to writing bullet-proof R
code.
For what's it's worth: it is only recently (only some R releases ago)
that the language/parser gained the syntax for specifying an integer,
e.g. 2L.  I guess, before this the only option you had to get an
integer was through coercion, e.g. as.integer(2), storage.mode(), but
also tricks such as 2:2.  So in some sense from the parsers point of
view, everything was doubles in the beginning.  (disclaimer: I might
be missing something).

My $.02

/Henrik

PS. OT, but reading help(":") I just learned that a:b is not always
the same as rev(b:a).
>
> Thanks,
> Ben
>
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>

On 15 Sep 2010, at 03:23, Benjamin Tyner wrote:
> 2. So, assuming the answer to (1) is a resounding "no", does
anyone care to state an opinion regarding the philosophical or historical
rationale for why this is the case in R/S, whereas certain other interpreted
languages offer the option to perform strict type checking? Basically, I'm
trying to explain to someone from a perl background why the (apparent) lack of a
"use strict; use warnings;" equivalent is not a hindrance to writing
bullet-proof R code.
If they're from a Perl background, you might also want to point out to them
that (base) Perl doesn't do _any_ type checking at all, and converts types
as needed.  As in ...

$x = "0.0";
if ($x) ... # true
if ($x+0) ... # false

AFAIK, that's one of the main complaints that people have about Perl. 
"use strict" will just make sure that all variables have to be
declared before they're used, so you can't mess up by mistyping variable
names.  Which is something I'd very much like to have in R occasionally ...

Best,
Stefan

---------- Forwarded message ----------
From: Karl Forner <karl.forner@gmail.com>
Date: Wed, Sep 15, 2010 at 10:14 AM
Subject: Re: [Rd] warning or error upon type/storage mode coercion?
To: Stefan Evert <stefanML@collocations.de>


I'm a Perl fan, and I really really miss the "use strict" feature.
IMHO it's
very error-prone not to have thios safety net.

Best,



On Wed, Sep 15, 2010 at 9:54 AM, Stefan Evert
<stefanML@collocations.de>wrote:
>
> On 15 Sep 2010, at 03:23, Benjamin Tyner wrote:
>
> > 2. So, assuming the answer to (1) is a resounding "no", does
anyone care
> to state an opinion regarding the philosophical or historical rationale for
> why this is the case in R/S, whereas certain other interpreted languages
> offer the option to perform strict type checking? Basically, I'm trying
to
> explain to someone from a perl background why the (apparent) lack of a
"use
> strict; use warnings;" equivalent is not a hindrance to writing
bullet-proof
> R code.
>
> If they're from a Perl background, you might also want to point out to
them
> that (base) Perl doesn't do _any_ type checking at all, and converts
types
> as needed.  As in ...
>
> $x = "0.0";
> if ($x) ... # true
> if ($x+0) ... # false
>
> AFAIK, that's one of the main complaints that people have about Perl. 
"use
> strict" will just make sure that all variables have to be declared
before
> they're used, so you can't mess up by mistyping variable names. 
Which is
> something I'd very much like to have in R occasionally ...
>
> Best,
> Stefan
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
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