On 07/06/2013 14:49, Bert Gunter wrote:
Folks:
Feel free to provide me a link or reference instead of an answer.
Preamble:
f <- function() function(x)rnorm(x)
g <- f()
g(3)
## [1] -0.4448492 -0.2379978 -0.4537394
## But
rnorm <- function()1 ## nasty nasty
g(3)
## Error in rnorm(x) : unused argument(s) (x)
## of course f <- function()function(x)stats:::rnorm(x)
## would fix this.
Question 1:
Suppose I defined f() as at top in a package namespace and exported it.
Would a user see this same error defining g() and with rnorm redefined
as above? (Assume stats is attached as usual). I presume so, but ...
Not if done right. The package should importFrom(stats, rnorm).
Question 2:
If the answer to Q1 is yes, (how) can this be avoided without using fully
qualified function names?
Again, a quick reference to relevant docs would suffice.
'Writing R Extensions' says
'The namespace controls the search strategy for variables used by functions
in the package. If not found locally, R searches the package namespace
first, then the imports, then the base namespace and then the normal search
path.'
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595