R devel - Feb 2013 - Printing of anonymous functions in calls is sub-optimal

e.g.

substitute(f(x), list(f = function(x) x + 1))
# function (x)
# x + 1(x)

An extra pair of parentheses would really help:

(function(x)
x + 1)(x)

(Better indenting etc would be nice, but not necessary for correct
understand of the code)

Hadley

-- 
Chief Scientist, RStudio
http://had.co.nz/

As there has been no response to this ...

Why not simply:
> g <- substitute(f(x),list(f=function(x){x+1})) ## with curly braces
> g
function (x)
{
    x + 1
}(x)
> x <- 2
> eval(g)
[1] 3


Cheers,
Bert

On Fri, Feb 15, 2013 at 7:45 AM, Hadley Wickham <h.wickham at gmail.com>
wrote:
> e.g.
>
> substitute(f(x), list(f = function(x) x + 1))
> # function (x)
> # x + 1(x)
>
> An extra pair of parentheses would really help:
>
> (function(x)
> x + 1)(x)
>
> (Better indenting etc would be nice, but not necessary for correct
> understand of the code)
>
> Hadley
>
> --
> Chief Scientist, RStudio
> http://had.co.nz/
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel


-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm

On 13-02-15 10:45 AM, Hadley Wickham wrote:
> e.g.
>
> substitute(f(x), list(f = function(x) x + 1))
> # function (x)
> # x + 1(x)
>
> An extra pair of parentheses would really help:
>
> (function(x)
> x + 1)(x)
>
> (Better indenting etc would be nice, but not necessary for correct
> understand of the code)
This is a little tricky for the deparser.  It sees a call to a function 
which was determined by an expression.  Sometimes you want parens, 
sometimes you don't.  For example, if getfun(y) returns a function, it's
clearer to display a call as getfun(y)(x) than (getfun(y))(x).

I'll see if I can work out which kinds of expressions need to be 
parenthesized and implement it in the deparser.

Duncan