Tags and filters

A tag is a bare key (bug) or key:value (status:doing). A filter is a conjunction of terms over a task's tags — the one primitive every board, lane, and query is built from. Resist adding to the grammar until a board someone actually needs cannot be expressed.

term	matches
`status`	any task with a `status` tag or a `status:*` tag
`status:doing`	exactly that tag
`-status`	negation: tasks with no `status` tag — the inbox
`project:none`	the implicit value: tasks with no `project` tag. Works for every key (`working:none` is nobody); `status:inbox` is its alias for status
`is:open` / `is:closed` / `is:any`	closed-ness; `is:open` is implied
`archived` / `archived:any`	only archived tasks / archived ones too; left out otherwise (archived means "don't look at it")
`type:practice` / `type:any`	what kind of entity (board #2472): practices, policies, guidance. With no `type:` term a filter finds tasks only (a task is the implicit type: `type:task` is no type tag); `type:any` finds every kind
`#38`	the task with that number, open or closed (a number names one task; an explicit `is:` still applies)
`~word`	substring of title or body (case-insensitive); a number also matches task numbers that contain it (`~92` finds #92 and #1392)

import { compileFilter } from 'tosijs-virta'

const inbox = compileFilter('-status')
const uiBugs = compileFilter('project:tosijs-ui bug is:any')

const task = { tags: ['bug', 'project:tosijs-ui'], closedAt: null, num: 7, title: 'x', body: '' }
preview.textContent = `inbox: ${inbox(task)}, uiBugs: ${uiBugs(task)}`

test('the example evaluates both filters', () => {
  expect(preview.textContent).toBe('inbox: true, uiBugs: true')
})