#

# set +o errexit -o noglob -o nounset is assumed.

#

rtl_export_vars() {

	local _unsetfl=0; [ "x${1}" = "x-u" ] && { _unsetfl=1; shift; };

	while [ "${#}" -ge 2 ]; do

		if [ "${2:+1}" = 1 ]\

		|| [ "${_unsetfl}" -eq 1 ]; then

			case "${_unsetfl}" in

			0)	rtl_set_var_unsafe "${1}" "${2}"; export "${1}"; ;;

			1)	unset "${1}"; ;;

			esac;

		fi; shift 2;

	done;

};

rtl_filter_vars() {

	local _fn="${1}" _fnfl=0 _qchar="" _var_spec="" _vars="" _vname="" IFS;

	rtl_set_IFS_nl;

	for _var_spec in $(set); do

		case "${_qchar}" in

		"\"")	if [ "${_var_spec%\"}" != "${_var_spec}" ]; then

				_qchar="";

			fi;

			if [ "${_fnfl:-0}" -eq 1 ]; then

				_vars="$(rtl_lconcat "${_vars}" "${_var_spec}" "\n")";

			fi;

			continue; ;;

		"\'")	if [ "${_var_spec%\'}" != "${_var_spec}" ]; then

				_qchar="";

			fi;

			if [ "${_fnfl:-0}" -eq 1 ]; then

				_vars="$(rtl_lconcat "${_vars}" "${_var_spec}" "\n")";

			fi;

			continue; ;;

		*)	case "${_var_spec}" in

			[!=]*=\"*\")	_qchar=""; _vname="${_var_spec%%=\"*}"; ;;

			[!=]*=\"*)	_qchar="\""; _vname="${_var_spec%%=\"*}"; ;;

			[!=]*=\'*\')	_qchar=""; _vname="${_var_spec%%=\'*}"; ;;

			[!=]*=\'*)	_qchar="\'"; _vname="${_var_spec%%=\'*}"; ;;

			[!=]*=*)	_qchar=""; _vname="${_var_spec%%=*}"; ;;

			esac; ;;

		esac;

		if "${_fn}" "${_vname}"; then

			_vars="${_vars:+${_vars}

}${_var_spec}"; _fnfl=1;

		else

			_fnfl=0;

		fi;

	done;

	printf "%s" "${_vars}";

};

rtl_head() {

	local _pattern="${1}" _s="${2}";

	while true; do

		if [ "${_s%%${_pattern}}" = "${_s}" ]; then

			break;

		else

			_s="${_s%%${_pattern}}";

		fi;

	done;

	printf "%s" "${_s}";

};

rtl_percentage() {

	local _in="${1}" _max="${2}" _perc;

	_perc="$((100 * ${_in} + ${_max} / 2))";

	_perc="$((${_perc} ? ${_perc} / ${_max} : ${_perc}))";

	printf "%d\n" "${_perc}";

};

rtl_sunset() {

	local _rs_rset="${1#\$}" _rs_kname="" IFS=" 	";

	eval set -- '${'"${_rs_rset}"'}';

	while [ "${#}" -gt 0 ]; do

		unset "${_rs_rset}${_rs_kname}"; shift;

	done; unset "${_rs_rset}";

};

# vim:filetype=sh