/
futureAssign_OP.R
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/
futureAssign_OP.R
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#' @usage x \%<-\% value
#'
#' @rdname future
#' @aliases %<-% %->%
#' @export %<-% %->%
`%<-%` <- function(x, value) {
target <- substitute(x)
expr <- substitute(value)
envir <- parent.frame(1)
futureAssignInternal(target, expr, envir = envir, substitute = FALSE)
}
`%->%` <- function(value, x) {
target <- substitute(x)
expr <- substitute(value)
envir <- parent.frame(1)
futureAssignInternal(target, expr, envir = envir, substitute = FALSE)
}
#' @importFrom listenv get_variable parse_env_subset
futureAssignInternal <- function(target, expr, envir = parent.frame(), substitute = FALSE) {
target <- parse_env_subset(target, envir = envir, substitute = substitute)
assign.env <- target$envir
name <- target$name
if (inherits(target$envir, "listenv")) {
n <- length(target$exists)
if (n == 0L) {
stop("Cannot future assign to an empty set")
} else if (n > 1L) {
stop("Cannot future assign to more than one element")
}
if (target$exists) {
name <- get_variable(target$envir, target$idx, mustExist = TRUE, create = FALSE)
} else {
if (!is.na(name) && nzchar(name)) {
name <- get_variable(target$envir, name, mustExist = FALSE, create = TRUE)
} else if (all(is.finite(target$idx))) {
name <- get_variable(target$envir, target$idx, mustExist = FALSE, create = TRUE)
} else if (all(is.na(target$idx))) {
stop("subscript out of bounds")
} else {
stop("INTERNAL ERROR: Zero length variable name and unknown index.")
}
}
}
futureAssign(name, expr, envir = envir, assign.env = assign.env, substitute = FALSE)
} # futureAssignInternal()