getters.R at 0221e18 ⋅ tidyverse/magrittr

#' Extract function(s) from a functional sequence.
#'
#' Functional sequences can be subset using single or double brackets.
#' A single-bracket subset results in a new functional sequence, and 
#' a double-bracket subset results in a single function. 
#'
#' @rdname fseq
#' @param x A functional sequence
#' @param ... index/indices. For double brackets, the index must be of length 1.
#' @return A function or functional sequence.
#' @export
`[[.fseq` <- function(x, ...)
{
  functions(x)[[...]]
}

#' @rdname fseq
#' @export
`[.fseq` <- function(x, ...)
{
  y  <- x
  environment(y) <- new.env(parent = parent.env(environment(x)))
  environment(y)[["_function_list"]] <- functions(x)[...]
  y
}

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1		#' Extract function(s) from a functional sequence.
2		#'
3		#' Functional sequences can be subset using single or double brackets.
4		#' A single-bracket subset results in a new functional sequence, and
5		#' a double-bracket subset results in a single function.
6		#'
7		#' @rdname fseq
8		#' @param x A functional sequence
9		#' @param ... index/indices. For double brackets, the index must be of length 1.
10		#' @return A function or functional sequence.
11		#' @export
12		`[[.fseq` <- function(x, ...)
13		{
14	0	functions(x)[[...]]
15		}
16
17		#' @rdname fseq
18		#' @export
19		`[.fseq` <- function(x, ...)
20		{
21	0	y <- x
22	0	environment(y) <- new.env(parent = parent.env(environment(x)))
23	0	environment(y)[["_function_list"]] <- functions(x)[...]
24	0	y
25		}