why did coprocs fd not exist, in this sample submissed on an issue as answer

[Alex fxmbsw7 Ratchev]

s=ab34 ; awksplit() { gawk -v FS= -v RS=\\0 -v ORS=\\0 -e '{ gsub( /./,
"\\\\& " ) ; print }' "$@" ; } ; declare -a "one=( $( awksplit <<<"$s" -v
ORS= ) )" ; declare -p one  ; [[ ! -v ser ]] && coproc ser { awksplit ; } ;
ser() { printf %s\\0 "${@:2}" >&${ser[1]} ; declare -ga "$1=( $( <
/proc/fd/$ser ) )" ; declare -p $1 ; } ; ser serial "$s"

declare -a one=([0]="a" [1]="b" [2]="3" [3]="4")
[1] 17511
bash: /proc/fd/57: No such file or directory
declare -a serial=()

besides the [[ -v ser doesnt work, i suspect ser[0] may