Thread subqueries

[David Bremner]

Tomi Ollila <tomi.ollila at iki.fi> writes:
>
> question: how does these differ (processing-wise):
>
>          $ notmuch count  'thread:"date:1month..now tag:dkg"'

the thread field processor receives the string "date:1month..now tag:dkg"
(without the quotes) which it treats as a thread id, and doesn't match
anything

>          $ notmuch count  'thread:{date:1month..now tag:dkg}'

the t.f.p. receives the string "{date:1month..now"
(without quotes) because the top level query parser splits at spaces,
unless prevented by "". This it considers syntactically invalid, rather
than silently dropping the second term.

>          $ notmuch count 'thread:"{date:1month..now tag:dkg}"'

The t.f.p. receives the string "{date:1month..now tag:dkg}" (without
quotes). It notes the first and last character, and triggers a subquery
expansion.

The thing to keep in mind is that we have no control over the top level
"tokenization" by Xapian, except for using "".