[R] dump not evaluating promises?

Duncan Murdoch murdoch.duncan at gmail.com
Fri Apr 30 18:57:32 CEST 2010


On 30/04/2010 12:07 PM, D Sonderegger wrote:
> dump and dput but have the same behavior but dump has an extra option
> 'evaluate'. From the documentation, 'evaluate=TRUE' looks like it should
> force promises to be evaluated, ie convert 1:6 to be c(1,2,3,4,5,6).  
>   

Both 1:6 and c(1,2,3,4,5,6) are expressions, and they evaluate to 
different things.  (1:6 is an integer vector, the other is a "numeric" 
vector, stored in floating point.)  dump() is just trying to give more 
concise output.  Look more closely at Peter's example.

Duncan Murdoch
> I think that either my understanding of what a 'promise' is and what it
> means to be evaluated is flawed, or the evaluate option in the dump command
> is broken.
>



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