Target pattern syntax
=====================

The BUILD file label syntax is used to specify a single target. Target
patterns generalize this syntax to sets of targets, and also support
working-directory-relative forms, recursion, subtraction and filtering.
Examples:

Specifying a single target:

  //foo/bar:wiz     The single target '//foo/bar:wiz'.
  foo/bar/wiz       Equivalent to:
                      '//foo/bar/wiz:wiz' if foo/bar/wiz is a package,
                      '//foo/bar:wiz' if foo/bar is a package,
                      '//foo:bar/wiz' otherwise.
  //foo/bar         Equivalent to '//foo/bar:bar'.

Specifying all rules in a package:

  //foo/bar:all       Matches all rules in package 'foo/bar'.

Specifying all rules recursively beneath a package:

  //foo/...:all     Matches all rules in all packages beneath directory 'foo'.
  //foo/...           (ditto)

Working-directory relative forms:  (assume cwd = 'workspace/foo')

  Target patterns which do not begin with '//' are taken relative to
  the working directory.  Patterns which begin with '//' are always
  absolute.

  ...:all           Equivalent to  '//foo/...:all'.
  ...                 (ditto)

  bar/...:all       Equivalent to  '//foo/bar/...:all'.
  bar/...             (ditto)

  bar:wiz           Equivalent to '//foo/bar:wiz'.
  :foo              Equivalent to '//foo:foo'.

  bar               Equivalent to '//foo/bar:bar'.
  foo/bar           Equivalent to '//foo/foo/bar:bar'.

  bar:all           Equivalent to '//foo/bar:all'.
  :all              Equivalent to '//foo:all'.

Summary of target wildcards:

  :all,             Match all rules in the specified packages.
  :*, :all-targets  Match all targets (rules and files) in the specified
                      packages, including .par and _deploy.jar files.

Subtractive patterns:

  Target patterns may be preceded by '-', meaning they should be
  subtracted from the set of targets accumulated by preceding
  patterns. (Note that this means order matters.) For example:

    % %{product} build -- foo/... -foo/contrib/...

  builds everything in 'foo', except 'contrib'.  In case a target not
  under 'contrib' depends on something under 'contrib' though, in order to
  build the former %{product} has to build the latter too. As usual, the '--' is
  required to prevent '-f' from being interpreted as an option.

%{options}