Tag Search Field, allowing Boolean Search (AND, OR, NOT, parentheses)

Thanks for making GTDnext. Rather than you having to make lots of different lists, could you create a Tag Search Field, allowing Boolean Search (AND, OR, NOT, parentheses) for tags, which would allow users to use GTD contexts based on tag searches like (#morning AND (#phone OR #errands) AND #Jackie) or ((NOT #energyHigh) AND #DurationShort).

A related enhancement would be saved searches, which become, in effect, custom lists.
Thanks!