Please don't ever use this, this is for demonstration only, if you're actually trying to implement a map in bash for production purposes, you may want to rethink that.
if you'd like to test this code: source the map.sh file and then create a varible (with a unique string) which will be the map, you can then call the functions, passing the map to the functions.
source map.sh
map=$MAPLOCATION
map_insert $map $key $value
map_retrieve $map $key