is.function               package:base               R Documentation

Is an Object of Type (Primitive) Function?

Description:

     Checks whether its argument is a (primitive) function.

Usage:

     is.function(x)
     is.primitive(x)

Arguments:

       x: an R object.

Details:

     'is.primitive(x)' tests if 'x' is a primitive function (either a
     '"builtin"' or '"special"' as described for 'typeof')?

Value:

     'TRUE' if 'x' is a (primitive) function, and 'FALSE' otherwise.

Examples:

     is.function(1) # FALSE
     is.function(is.primitive)  # TRUE: it is a function, but ..
     is.primitive(is.primitive) # FALSE:it's not a primitive one, whereas
     is.primitive(is.function)  # TRUE: that one *is*

