R/0_dependencies.R

In lifecontingencies: Financial and Actuarial Mathematics for Life Contingencies

#############################################################################
#   Copyright (c) 2018 Giorgio A. Spedicato
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
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#   This program is distributed in the hope that it will be useful,
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#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
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#   along with this program; if not, write to the
#   Free Software Foundation, Inc.,
#   59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
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#############################################################################
###
###         dependency helpers
###

.require_markovchain <- function(function_name) {
	if (!requireNamespace("markovchain", quietly = TRUE)) {
		warning(
			paste0(
				"`", function_name, "` requires the 'markovchain' package. ",
				"Install it with install.packages(\"markovchain\")."
			),
			call. = FALSE
		)
		return(FALSE)
	}

	TRUE
}