On 16/03/2011 4:14 PM, Ryan King wrote:
I've recently hunted down a troublesome bug in my own code, and am
looking for an easy mechanism to detect this kind of error in other R
code. The problem was an undefined variable inside of a function.
Unfortunately, R looked for that variable in the global environment
and found it since there was variable with that name in my testing
scripts (note to self: do not name things "x").
Is there an easy way to report all the non-local objects accessed in a
function?
The problem is that all base functions are non-local objects, so you
probably don't want to do exactly that, but the codetools package can do
it (using tools::findGlobals) and also provides help in identifying
errors. You say you keep your code in a package (which is a good idea)
so you should run "R CMD check" on the package. If your code is not in
a package, use tools::checkUsage or related functions.
Is there any easy way around the usual scoping rules? I want to be
able to get to base functions, and am willing to namespace:: or :::
access all of my own functions (it's in a package) if necessary to
block the standard scoping rules. The language def section on
environments made me hurt.
Quoting Uwe Ligges, "No".
Duncan Murdoch
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