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#
# Copyright (c) Microsoft. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
#' @export
iter.foreach <- function(obj, ..., extra=list()) {
# evaluate the quoted iteration variables, and turn them into iterators
iargs <- lapply(obj$args, function(a) iter(eval(a, envir=extra,
enclos=obj$evalenv), ...))
# create the environment that will contain our dynamic state
state <- new.env(parent=emptyenv())
# iterator state
state$stopped <- FALSE
state$numValues <- 0L # number of values that we've fired
# accumulator state
combineInfo <- obj$combineInfo
if (combineInfo$has.init) {
state$accum <- eval(combineInfo$init, envir=extra, enclos=obj$evalenv)
state$first.time <- FALSE
} else {
state$accum <- NULL
state$first.time <- TRUE
}
state$fun <- combineInfo$fun
state$buffered <- rep(as.integer(NA), 2 * combineInfo$max.combine)
state$next.tag <- 1L # only used when in.order is TRUE
state$buf.off <- 0L # only used when in.order is TRUE
state$nbuf <- 0L # only used when in.order is FALSE
state$numResults <- 0L # number of results that we've received back
state$errorValue <- NULL
state$errorIndex <- -1L
# package and return the iterator object
iterator <- list(state=state, iargs=iargs, argnames=obj$argnames,
combineInfo=combineInfo, errorHandling=obj$errorHandling,
verbose=obj$verbose)
class(iterator) <- c('iforeach', 'iter')
iterator
}
#' @export
iter.xforeach <- function(obj, ...) {
state <- new.env(parent=emptyenv())
state$stopped <- FALSE
state$fired <- integer(0)
state$ie2 <- list()
state$errorValue <- NULL
state$errorIndex <- -1L
ie1 <- iter(obj$e1, ...)
iterator <- list(state=state, ie1=ie1, e2=obj$e2, argnames=obj$argnames,
errorHandling=obj$errorHandling, verbose=obj$verbose)
class(iterator) <- c('ixforeach', 'iter')
iterator
}
#' @export
iter.filteredforeach <- function(obj, ...) {
ie1 <- iter(obj$e1, ...)
iterator <- list(ie1=ie1, qcond=obj$qcond, evalenv=obj$evalenv,
argnames=obj$argnames, errorHandling=obj$errorHandling,
verbose=obj$verbose)
class(iterator) <- c('ifilteredforeach', 'iter')
iterator
}
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