call {base}R Documentation

Function Calls

Description

Create or test for objects of mode "call".

Usage

call(name, ...)
is.call(x)
as.call(x)

Arguments

name a character string naming the function to be called.
... arguments to be part of the call.
x an arbitrary R object.

Details

call returns an unevaluated function call, that is, an unevaluated expression which consists of the named function applied to the given arguments (name must be a quoted string which gives the name of a function to be called).

is.call is used to determine whether x is a call (i.e., of mode "call"). It is generic: you can write methods to handle specific classes of objects, see InternalMethods.

Objects of mode "list" can be coerced to mode "call". The first element of the list becomes the function part of the call, so should be a function or the name of one (as a symbol; a quoted string will not do).

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

do.call for calling a function by name and argument list; Recall for recursive calling of functions; further is.language, expression, function.

Examples

is.call(call) #-> FALSE: Functions are NOT calls

# set up a function call to round with argument 10.5
cl <- call("round", 10.5)
is.call(cl)# TRUE
cl
# such a call can also be evaluated.
eval(cl)# [1] 10

[Package base version 2.1.0 Index]