#!/bin/bash

oifs=$IFS

inner () {
#recho inner: "$IFS" >&2
	echo a/b/c/d
	exit 0
}

outer() {
#recho outer: "$IFS" >&2
for i in 1; do
	IFS=/ read m v k a < <(IFS=$oifs inner)

echo $m:$v:$k:$a
done
}

outer
unset m k v a b c d

for j in 1; do
	IFS=: read a b c d
done < <(outer)

echo $a-$b-$c-$d
unset m k v a b c d

IFS=: read a b c d < <(outer)

echo $a:$b:$c:$d