progloop

#!/usr/bin/env bash

declare -a output
declare -A values

usage() {
	echo "$0 INITIALSPEED ENDSPEED INCREMENT [files]"
}

if (( $# < 3 )); then
	usage
	exit 1
fi

for lbl in 'initialspeed' 'endspeed' 'increment'; do
	re='^[0-9]+$'
	if ! [[ "$1" =~ $re ]] ; then
		echo >&2 "error: ${lbl^^} not a number"
		usage
		exit 1
	fi
	values["$lbl"]="$1"
	shift
done

add_tempo() {
	mapfile -t input < <(sed '/^[0-9]+$/d' <<< "$1")
	for ((i="${values['initialspeed']}"; i<="${values['endspeed']}"; i+="${values['increment']}")); do
		output+=( "$i" "${input[@]}" )
	done
}

if (( $# > 0 )); then
	add_tempo <(cat "$@")
else
	add_tempo /dev/stdin
fi

printf '%s\n' "${output[@]}"
# aoss "$HOME/src/jdkdrum/jdkdrum" < <(printf '%s\n' "${output[@]}")