Manage chat with one command (with subsections)

To be clearer, this command would allow you to manage the Minecraft chat, read new messages, store them in something (nbt of an object for example), etc...

Like, to illustrate what I'm saying, a /chat <if|get> <string>.

For example, if you want to get the sentence's string of the last message, you just have to enter this command "/chat get". And you can detect a certain message issued in the chat by using "/chat if "message"".

PS: I received suggestions to say at the same time that mojang could add the fact that you can store a <string> in a score. This would avoid a new order. (thanks Leirof)

Thank you for reading me, and for voting for those who did ^^