Proposal For a new Execute subcommand

Recently I have gotten into making data packs, and one thing that really want to be able to do ingame and not have to write a function to do: is to be able to read data from command storage, and use it in a command, something that can be done very easily with a macro function. 

My idea: the with subcommand for the execute command.

the syntax for this subcommand is as follows:

...with <storage> <path> <key> --> execute

where <storage> is a resource location for a storage entity, <path> is a NBT path argument, and <key> is a string. 

once that subcommand is complete, you may reference a key by writing $(<key>), which would be replaced by whatever value the key contains. 

If this is added, it would revolutionize the way command storage is used