DOM - Document Object Model
===========================
Timewarrior needs DOM support, so that it can service a 'get' command and
provide access to data and rules. Both are important for extensions.


Data to be Accessed
-------------------
Here are the data accessible via DOM references:

- Configuration
- Exclusions
- Command line args in raw form (for rules, not 'get')


Syntax
------
All DOM references have this form:

  dom.<name>


Supported Names
---------------

  dom.tag.count                   --> 14                   Count of all tags
  dom.tag.1                      --> 'tag'                 Nth tag used

  dom.active                      --> 0/1                  Boolean indicator that tracking is active
  dom.active.tag.count            --> N                    Count of active tags
  dom.active.tag.1                --> 'tag'                Active Nth tag
  dom.active.start                --> YYYY-MM-DDTHH:MM:SS  Active start time
  dom.active.duration             --> PT1H25M8S            Active elapsed
  dom.active.json                 --> {...}                Active interval as JSON

  dom.tracked.count               --> N                    Count of tracked intervals
  dom.tracked.1.tag.count         --> N                    Tracked Nth, count of tags
  dom.tracked.1.tag.1             --> 'tag'                Tracked Nth, Nth tag
  dom.tracked.1.start             --> YYYY-MM-DDTHH:MM:SS  Tracked Nth, start time
  dom.tracked.1.end               --> YYYY-MM-DDTHH:MM:SS  Tracked Nth, end time, blank if closed
  dom.tracked.1.duration          --> PT1H25M8S            Tracked Nth, elapsed
  dom.tracked.1.json              --> {...}                Tracked Nth, interval as JSON

--- Raw Notes ---

Proposed:

  dom.tag.[1-3]                   --> 't1', 't2', 't3'    First three tags
  dom.tag.[1,2,3]                 --> 't1', 't2', 't3'    First three tags
  dom.tag.*                       --> 't1', ... 't14'     All tags


  dom.tracked.year                --> 231                 Quantity this year
  dom.tracked.quarter             --> 64                  Quantity this quarter
  dom.tracked.month               --> 21                  Quantity this month
  dom.tracked.week                --> 6                   Quantity this week
  dom.tracked.today               --> 2                   Quantity today

  dom.gap.today
  ...

  rc.<name>


- The above does not support totals, as this would turn DOM references into a
  query language. Instead, a 'sum' command could do this. The rules.txt doc
  already mentions built-in functions.