1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
\name{attr-operators}
\alias{\%#\%}
\alias{\%##\%}
\alias{\%@\%}
\alias{\%@\%<-}
\title{Operators for Setting Annotations and Attributes}
\description{The operator \code{\%#\%} can be used to attach a
\code{\link{description}} annotation to an object. \code{\%##\%} can be
used to attach a character vector of annotations to an object.
\code{\%@\%} returns the attribute with the name given as second
argument. With \code{\%@\%} it is also possible to assign attributes.
}
\usage{
x \%#\% descr
x \%##\% annot
x \%@\% nm
x \%@\% nm <- value
}
\arguments{
\item{x}{an object, usually and \code{\link{item}} or a vector.}
\item{descr}{a character string}
\item{annot}{a named character vector; its contents are added to the
"annotation" attribute of \code{x}. Existing elements are kept.}
\item{nm}{a character string, the name of the attribute being set or
requested.}
\item{value}{any kind of object that can be attached as an attribute.}
}
\examples{
test1 <- 1 \%#\% "One"
# This is equivalent to:
# test <- 1
# description(test) <- "One"
description(test1)
# Results in "One"
# Not that it makes sense, but ...
test2 <- 2 \%##\% c(
Precedessor = 0,
Successor = 2
)
# This is equivalent to:
# test2 <- 2
# annotation(test2) <- c(
# Precedessor = 0,
# Successor = 2
# )
annotation(test2)
# The following examples are equivalent to
# attr(test2,"annotation")
test2 \%@\% annotation
test2 \%@\% "annotation"
test2 \%@\% another.attribute <- 42
# This is equivalent to attr(test2,"another.attribute") <- 42
attributes(test2)
}
|
