R devel - Sep 2014 - Can't Find Function After requireNamespace

I have a simple function :

f <- function()
{
  if(requireNamespace("ggplot2"))
    qplot(Sepal.Length, Petal.Length, data = iris, color = Species)
  else
    message("No graphics, just text.")
}

ggplot2 is in the Suggests field of the DESCRIPTION file. When I load the
package, and run the function, I get an error :
> f()
Loading required namespace: ggplot2
Error in f() : could not find function "qplot"

I don't want all ggplot2 functions to be added to the search path, so I am
not using require(ggplot2). How can I use it correctly ?

R version 3.1.1 (2014-07-10)
Platform: x86_64-unknown-linux-gnu (64-bit)

--------------------------------------
Dario Strbenac
PhD Student
University of Sydney
Camperdown NSW 2050
Australia

On Sep 17, 2014, at 10:00 PM, Dario Strbenac <dstr7320 at
uni.sydney.edu.au> wrote:
> I have a simple function :
> 
> f <- function()
> {
>  if(requireNamespace("ggplot2"))
>    qplot(Sepal.Length, Petal.Length, data = iris, color = Species)
>  else
>    message("No graphics, just text.")
> }
> 
> ggplot2 is in the Suggests field of the DESCRIPTION file. When I load the
package, and run the function, I get an error :
> 
>> f()
> Loading required namespace: ggplot2
> Error in f() : could not find function "qplot"
> 
> I don't want all ggplot2 functions to be added to the search path, so I
am not using require(ggplot2). How can I use it correctly ?
> 
ggplot2::qplot(Sepal.Length, Petal.Length, data = iris, color = Species)

Cheers,
S

> R version 3.1.1 (2014-07-10)
> Platform: x86_64-unknown-linux-gnu (64-bit)
> 
> --------------------------------------
> Dario Strbenac
> PhD Student
> University of Sydney
> Camperdown NSW 2050
> Australia
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