[Rd] parsing difference between 2.4.1 and 2.5.0

[Duncan Murdoch]

On 4/27/2007 12:55 PM, Duncan Murdoch wrote:
> On 4/27/2007 11:34 AM, Gabor Grothendieck wrote:
>> I noticed the following difference in parse(text = ...) between R
>> 2.4.1 and R 2.5.0.
>> 
>> ===
>> 
>>> parse(text = "\"^\" (x ,2 )")
>> expression(x^2)
>>> R.version.string
>> [1] "R version 2.4.1 Patched (2006-12-30 r40331)"
>> 
>> 
>> ====
>> 
>>> parse(text = "\"^\" (x ,2 )")
>> expression("^" (x ,2 ))
>>> R.version.string
>> [1] "R version 2.5.0 RC (2007-04-16 r41194)"
>> 
>> ====
>> 
>> Ryacas was depending on the behavior in R 2.4.1 so the new
>> behavior breaks it.
>> 
>> Is this intentional?  a bug?  How do I get the R 2.4.1 output
>> from R 2.5.0 ?
> 
> There's no difference in the parsing, 

This isn't quite true, of course:  in 2.5.0 the default parse output 
includes an attribute that references the original source.  I think the 
rest of what I wrote is right:

the difference is in the printing.
>   By default 2.5.0 will echo what you typed, whereas 2.4.1 will deparse. 
>   You can get the 2.4.1 behaviour using options(keep.source=F) or 
> parse(text = "\"^\" (x ,2 )", srcfile=NULL) (as ?parse says).
> 
> Duncan Murdoch
> 
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