Need to provide a way for a query to modify the language used to parse the next command.
Example:
'emails from matt'
Displays all 'matt's with message "which matt do you mean? :"
modify the language:
looking_for {"matt meshulam", "matthew hahn"} to complete name in qf
qf is a query captured in a function that takes missing parts as parameters
looking_for is a function that dynamically generates a set of grammar to add to the base grammar.