[datatable-help] Error when using eval() in j

[Matthew Dowle]

Harish,

Thats a bug. I added #1026, fixed, +test 182, +NEWS and committed.

Thanks as always for reporting and for the nice reproducible example.

Matthew


On Sat, 2010-08-14 at 01:08 -0700, Harish wrote:
> I am running into an issue using a quote with eval in 'j'.  I think I had a similar issue with 'by' in the past; maybe it is a similar bug.
> 
> Use the following code to reproduce:
> ---------------------
> 
> foo <- function( data, fcn ) {
>    q <- substitute( fcn )
>    
>    # The following line works
>    #data[ , eval( q ), by=a ]
> 
>    # The following line causes an error
>    data[ , eval( substitute( fcn ) ), by=a ]
> }
> 
> num <- 10
> DT <- data.table( a=rep(c("A","B"),num), b=1:(num*2) )
> foo( DT, sum(b) )
> 
> ---------------------
> 
> Notice the two lines inside foo().  They should be logically equivalent, but only one works.
> 
> Is this a bug?
> 
> 
> Harish
> 
> 
> 
>       
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