R devel - Mar 2020 - substitute inconsistent output

Dear R-devel,

Is there anything that we can do to make output of those call more
consistent? So the first one will return `c(1L, 2L)` rather than
`1:2`. Note that it is not related to compact integer sequence
introduced by altrep, it is reproducible on R 3.1.0 as well.

substitute(v+x, list(x=c(1L,2L)))
#v + 1:2
substitute(v+x, list(x=c(0L,2L)))
#v + c(0L, 2L)

Thank you,
Jan Gorecki

On 18/03/2020 1:36 a.m., Jan Gorecki wrote:
> Dear R-devel,
> 
> Is there anything that we can do to make output of those call more
> consistent? So the first one will return `c(1L, 2L)` rather than
> `1:2`. Note that it is not related to compact integer sequence
> introduced by altrep, it is reproducible on R 3.1.0 as well.
> 
> substitute(v+x, list(x=c(1L,2L)))
> #v + 1:2
> substitute(v+x, list(x=c(0L,2L)))
> #v + c(0L, 2L)
> 
That's purely the deparser (the returned value from substitute doesn't 
contain a call to ":"), but it's not optional.

So the output is consistent, it's the printing that is inconsistent.

Duncan Murdoch