rtttl.sh -- Play Nokia Composer Music Notation (RTTTL)

#!/usr/bin/bash
# rtttl.sh -- Nokia Composer RTTTL Player
# Requirement: SOX Play ($ sudo apt install sox libsox-fmt-all)
# Usage: rtttl.sh "Cola:d=4,o=5,b=125:8f#6,8f#6,8f#6,8f#6,g6,8f#6,e6,8e6,8a6,f#6,d6,2p"
# Usage: rtttl.sh "16e2 16d2 8#f1 8#g1 16c#2 16b1 8d1 8e1 16b1 16a1 8#c1 8e1 16a1"
a=${*//,/ }
d=4
o=1
b=63
if [[ "$a" == *:* ]]; then
    a="${a#*:}"
    for field in ${a%%:*}; do
        case "$field" in
            d=*) d="${field#d=}" ;;
            o=*) o="${field#o=}" ;;
            b=*) b="${field#b=}" ;;
        esac
    done
    a="${a#*:}"
fi
play="/usr/bin/play -n "
for token in $a; do
    if [[ "$token" =~ ^([0-9]*)?(\.?)(#?)([a-gp-])(#?)([0-9]*)$ ]]; then
        dur=$(( $( [[ -n "${BASH_REMATCH[2]}" ]] && echo 360000 || echo 240000 ) / $b / ${BASH_REMATCH[1]:-$d} ))
        dur=$(echo "scale=3; $dur/1000" | bc)
        #echo "(DUR $dur)"
        if [[ ${BASH_REMATCH[4]} == '-' ]] || [[ ${BASH_REMATCH[4]} == 'p' ]]; then
            play="${play} trim 0 ${dur} ':' "
        else
            note="${BASH_REMATCH[4]}${BASH_REMATCH[3]}${BASH_REMATCH[5]}$(( ${BASH_REMATCH[6]:-$o} % 5 + 5))"
            play="${play} synth ${dur} sin '${note^^}' ':' "
        fi
    fi
done
play="${play} trim 0 0"
echo "echo d=$d,o=$o,b=$b; $play"
eval $play