BBmisc (version 1.5)

checkArg: Check for a function argument.

Description

Throws exception if checks are not passed. Note that argument is evaluated when checked.

Usage

checkArg(x, cl, s4 = FALSE, len, min.len, max.len, choices, subset,
  lower = NA, upper = NA, na.ok = TRUE, formals)

Arguments

x

[any] Argument.

cl

[character] Class that argument must inherit from. If multiple classes are given, x must inherit from at least one of these. See also argument s4.

s4

[logical(1)] If TRUE, use is for checking class cl, otherwise use inherits, which implies that only S3 classes are correctly checked. This is done

len

[integer(1)] Length that argument must have. Not checked if not passed, which is the default.

min.len

[integer(1)] Minimal length that argument must have. Not checked if not passed, which is the default.

max.len

[integer(1)] Maximal length that argument must have. Not checked if not passed, which is the default.

choices

[any] Discrete number of choices, expressed by a vector of R objects. If passed, argument must be identical to one of these and nothing else is checked.

subset

[any] Discrete number of choices, expressed by a vector of R objects. If passed, argument must be identical to a subset of these and nothing else is checked.

lower

[numeric(1)] Lower bound for numeric vector arguments. Default is NA, which means not required.

upper

[numeric(1)] Upper bound for numeric vector arguments. Default is NA, which means not required.

na.ok

[logical(1)] Is it ok if a vector argument contains NAs? Default is TRUE.

formals

[character] If this is passed, x must be a function. It is then checked that formals are the names of the (first) formal arguments in the signature of x. Meaning checkArg(function(a, b),

Value

• Nothing.

Examples

x <- 1L
checkArg(x, "integer", len=1, na.ok=FALSE, upper=3L)
x <- as.integer(NA)
checkArg(x, "integer", len=1, na.ok=TRUE)
x <- c("foo", "bar")
checkArg(x, "character")
x <- "foo"
checkArg(x, choices=c("foo", "bar"))
x <- c("foo", "bar")
checkArg(x, subset=c("foo", "bar"))
fun <- function(foo, bar)
checkArg(fun, formals=c("foo", "bar"))