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% File src/library/base/man/is.function.Rd
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% Part of the R package, https://www.R-project.org
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% Copyright 1995-2018 R Core Team
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% Distributed under GPL 2 or later
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\name{is.function}
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\alias{is.function}
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\alias{is.primitive}
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\title{Is an Object of Type (Primitive) Function?}
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\usage{
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is.function(x)
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is.primitive(x)
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}
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\description{Checks whether its argument is a (primitive) function.}
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\arguments{
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  \item{x}{an \R object.}
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}
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\details{
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  \code{is.primitive(x)} tests if \code{x} is a \link{primitive} function,
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  i.e, if \code{\link{typeof}(x)} is either \code{"builtin"} or
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  \code{"special"}.
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}
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\value{
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  \code{TRUE} if \code{x} is a (primitive) function, and \code{FALSE}
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  otherwise.
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}
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\examples{
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is.function(1) # FALSE
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is.function (is.primitive) # TRUE: it is a function, but ..
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is.primitive(is.primitive) # FALSE: it's not a primitive one, whereas
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is.primitive(is.function)  # TRUE: that one *is*
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}
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\keyword{programming}