# Copyright 2016 Google Inc. 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.
#' Save a string representing the current context of the program flow.
#'
#' @param context (a string) context of the message; to be displayed in (error)
#' messages.
#' @return The previous message context strings (a character vector).
SetMessageContextString <- function(context) {
opt <- getOption("geoexperiments", default=list())
context.old <- opt[["context"]]
if (is.null(context.old)) {
opt.context <- character(0)
} else {
opt.context <- context.old
}
if (missing(context)) {
opt.context <- opt.context[-1L]
} else {
assert_that(is.nonempty.string(context),
msg="'context' must be a nonempty string")
opt.context <- c(context, opt.context)
}
opt["context"] <- list(opt.context)
options(geoexperiments=opt)
invisible(context.old)
}
#' Get the current message context string.
#'
#' @return The current message context string. If not available, returns an
#' empty string ("").
#'
#' @note
#' Pastes the strings together with '>'
GetMessageContextString <- function() {
kSeparator <- ">"
context.strings <- getOption("geoexperiments", default=list())[["context"]]
if (length(context.strings) == 0L) {
context.string <- ""
} else {
context.string <- paste(rev(context.strings), collapse=kSeparator)
}
return(context.string)
}
#' Form a message, prefixed with the message context string.
#'
#' @param ... R vectors, usually character, to be collapsed using 'paste0'.
#' @return A string.
Message <- function(...) {
prefix <- GetMessageContextString()
if (nchar(prefix) > 0L) {
prefix <- paste0(prefix, ": ")
}
paste0(prefix, ..., collapse="")
}
#' Form a message, using sprintf.
#'
#' @param fmt a character vector of format strings (see 'sprintf' for details).
#' @param ... values to be passed to 'fmt'.
#' @return A string.
Messagef <- function(fmt, ...) {
assert_that(is.nonempty.string(fmt))
Message(sprintf(fmt, ...))
}
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