[R-Forge #975] Multiple expressions in quote expression passed to by

[arunsrinivasan]

Submitted by: Matt Dowle; Assigned to: Nobody; R-Forge link

DT <- data.table( a=1:5, b=11:50, d=c("A","B","C","D") )
f <- quote( list(d) ) # ok
DT[ , mean(b), by=eval(f) ] # Now this works; thanks
foo <- function( grp ) {
DT[ , mean(b), by=eval( grp ) ]
}
foo( quote( list(d) ) ) # ok

but ...

foo( quote( list(d,a) ) )
Error in bysubl[[jj + 1]] : subscript out of bounds