[Rd] "+" for character method...

[Latchezar Dimitrov]

> -----Original Message-----
> From: r-devel-bounces at r-project.org 
> [mailto:r-devel-bounces at r-project.org] On Behalf Of Thomas Lumley
> Sent: Sunday, August 27, 2006 6:22 PM
> To: John Chambers
> Cc: R-devel at r-project.org
> Subject: Re: [Rd] "+" for character method...
> 
> On Sat, 26 Aug 2006, John Chambers wrote:
> 
> > Well, two comments, in two non-compatible directions.
> >
> > 1.  I have to say that I find the idea of using "+" to 
> paste character 
> > strings together aesthetically ugly.
> 
> Hear, hear!
> 
> In a language where you can define new binary operators 
> easily making the same operator do addition and concatenation 
> really doesn't seem a good idea. It is done in some other 
> languages, but so is using the same operator for printing and 
> multiplying by powers of two.
> 
> Lack of commutativity is obvious, but lack of associativity 
> seems much more dangerous. Suppose x, y, and z are a mixture 
> of strings and numbers. 
> Hands up everyone who knows (without cheating) whether x+y+z 
> would be interpreted the same way in R (with the current 
> parser) as in Java or Delphi or Python (and are these all the 
> same?).  Which of
>     "two + two = " + 2 + 2
>     2 + 2 + " = two + two"
> would be correct?

     "two + two = " * 2 + 2
     2 + 2 * " = two + two"

are both "correct" :-))

Latchezar Dimitrov
Analyst/Programmer
Wake Forest University School of Medicine

However the opinons are mine only.


> 
>  	-thomas
> 
> Thomas Lumley			Assoc. Professor, Biostatistics
> tlumley at u.washington.edu	University of Washington, Seattle
> 
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