Declarations Used in Checking a Package
globalVariables, the names supplied are of functions or
other objects that should be regarded as defined globally when the
check tool is applied to this package. The call to
globalVariables will be included in the package's source.
Repeated calls in the same package accumulate the names of the
Typical examples are the fields and methods in reference classes,
which appear to be global objects to
(This case is handled automatically by
friends, using the supplied field and method names.)
suppressForeignCheck, the names supplied are of variables
.NAME in foreign function calls which should not be
checkFF(registration = TRUE). Without this
declaration, expressions other than simple character strings are
assumed to evaluate to registered native symbol objects. The type of
.External, etc.) and argument counts will
be checked. With this declaration, checks on those names will usually
be suppressed. (If the code uses an expression that should only be
evaluated at runtime, the message can be suppressed by wrapping it in
dontCheck function call, or by saving it to a local
variable, and suppressing messages about that variable. See the
globalVariables(names, package, add = TRUE) suppressForeignCheck(names, package, add = TRUE)
- The character vector of object names. If omitted, the current list of global variables declared in the package will be returned, unchanged.
- The relevant package, usually the character string name of the package
but optionally its corresponding namespace environment.
When the call to
suppressForeignCheckcomes in the package's source file, the argument is normally omitted, as in the example below.
- Should the contents of
namesbe added to the current global variables or replace it?
The lists of declared global variables and native symbol objects are
stored in a metadata object in the package's namespace, assuming the
suppressForeignCheck call(s) occur
as top-level calls in the package's source code.
The check command, as implemented in package
the list before checking the R
globalVariablesreturns the current list of declared global variables, possibly modified by this call.
suppressForeignCheckreturns the current list of native symbol objects which are not to be checked.
The global variables list really belongs to a restricted scope (a
function or a group of method definitions, for example) rather than
the package as a whole. However, implementing finer control would
require changes in
check and/or in
codetools, so in this
version the information is stored at the package level.
suppressForeignCheck was introduced in R3.1.0 so both
should be used conditionally: see the example.
## assume your package has some code that assigns ".obj1" and ".obj2" ## but not in a way that codetools can find. ## In the same source file (to remind you that you did it) add: if(getRversion() >= "2.15.1") utils::globalVariables(c(".obj1", "obj2")) ## To suppress messages about a run-time calculated native symbol, ## save it to a local variable. ## At top level, put this: if(getRversion() >= "3.1.0") utils::suppressForeignCheck("localvariable") ## Within your function, do the call like this: localvariable <- if (condition) entry1 else entry2 .Call(localvariable, 1, 2, 3) ## Alternatively, like this: if(getRversion() < "3.1.0") dontCheck <- identity .Call(dontCheck(if (condition) entry1 else entry2), 1, 2, 3) ## HOWEVER, it is much better practice to write code ## that can be checked thoroughly, e.g. if(condition) .Call(entry1, 1, 2, 3) else .Call(entry2, 1, 2, 3)