Mercurial supports a functional language for selecting a set of
revisions.

The language supports a number of predicates which are joined by infix
operators. Parenthesis can be used for grouping.

Identifiers such as branch names must be quoted with single or double
quotes if they contain characters outside of
``[._a-zA-Z0-9\x80-\xff]`` or if they match one of the predefined
predicates. Special characters can be used in quoted identifiers by
escaping them, e.g., ``\n`` is interpreted as a newline.

There is a single prefix operator:

``not x``
  Changesets not in x. Short form is ``! x``.

These are the supported infix operators:

``x::y``
  A DAG range, meaning all changesets that are descendants of x and
  ancestors of y, including x and y themselves. If the first endpoint
  is left out, this is equivalent to ``ancestors(y)``, if the second
  is left out it is equivalent to ``descendants(x)``.

  An alternative syntax is ``x..y``.

``x:y``
  All changesets with revision numbers between x and y, both
  inclusive. Either endpoint can be left out, they default to 0 and
  tip.

``x and y``
  The intersection of changesets in x and y. Short form is ``x & y``.

``x or y``
  The union of changesets in x and y. There are two alternative short
  forms: ``x | y`` and ``x + y``.

``x - y``
  Changesets in x but not in y.

The following predicates are supported:

``adds(pattern)``
  Changesets that add a file matching pattern.

``all()``
  All changesets, the same as ``0:tip``.

``ancestor(single, single)``
  Greatest common ancestor of the two changesets.

``ancestors(set)``
  Changesets that are ancestors of a changeset in set.

``author(string)``
  Alias for ``user(string)``.

``branch(set)``
  The branch names are found for changesets in set, and the result is
  all changesets belonging to one those branches.

``children(set)``
  Child changesets of changesets in set.

``closed()``
  Changeset is closed.

``contains(pattern)``
  Revision contains pattern.

``date(interval)``
  Changesets within the interval, see :hg:`help dates`.

``descendants(set)``
  Changesets which are decendants of changesets in set.

``file(pattern)``
  Changesets which manually affected files matching pattern.

``follow()``
  An alias for ``::.`` (ancestors of the working copy's first parent).

``grep(regex)``
  Like ``keyword(string)`` but accepts a regex.

``head()``
  Changeset is a head.

``heads(set)``
  Members of set with no children in set.

``keyword(string)``
  Search commit message, user name, and names of changed files for
  string.

``limit(set, n)``
  First n members of set.

``max(set)``
  Changeset with highest revision number in set.

``merge()``
  Changeset is a merge changeset.

``modifies(pattern)``
  Changesets which modify files matching pattern.

``outgoing([path])``
  Changesets missing in path.

``p1(set)``
  First parent of changesets in set.

``p2(set)``
  Second parent of changesets in set.

``parents(set)``
  The set of all parents for all changesets in set.

``removes(pattern)``
  Changesets which remove files matching pattern.

``reverse(set)``
  Reverse order of set.

``roots(set)``
  Changesets with no parent changeset in set.

``sort(set[, [-]key...])``
  Sort set by keys. The default sort order is ascending, specify a key
  as ``-key`` to sort in descending order.

  The keys can be:

  - ``rev`` for the revision number,
  - ``branch`` for the branch name,
  - ``desc`` for the commit message (description),
  - ``user`` for user name (``author`` can be used as an alias),
  - ``date`` for the commit date

``tagged()``
  Changeset is tagged.

``user(string)``
  User name is string.

Command line equivalents for :hg:`log`::

  -f    ->  ::.
  -d x  ->  date(x)
  -k x  ->  keyword(x)
  -m    ->  merge()
  -u x  ->  user(x)
  -b x  ->  branch(x)
  -P x  ->  !::x
  -l x  ->  limit(expr, x)

Some sample queries::

  hg log -r 'branch(default)'
  hg log -r 'branch(default) and 1.5:: and not merge()'
  hg log -r '1.3::1.5 and keyword(bug) and file("hgext/*")'
  hg log -r 'sort(date("May 2008"), user)'
  hg log -r '(keyword(bug) or keyword(issue)) and not ancestors(tagged())'
