Dynamically filling file descriptors in sh(1)

#!/bin/sh
fdset="3 4 5 6 7 8 9"
data3="1"
data4="2"
data5="3"
data6="4"
data7="5"
data8="6"
data9="7"
for n in $fdset; do
    eval data=\"\$data$n\"
    exec 9<<-EOF
    $( echo "$data" )
    EOF
    [ $n -eq 9 ] || eval exec "$n<&9" "9<&-"
done
for n in $fdset; do
    data=$( eval cat \<\&$n )
    echo "data on fd($n): $data"
done