Package and Set Dependency Specifications

Dependency specifications can look like:

set: A simple set name. Only supported where a named set makes sense.
pkg: A simple package name. Not supported in configuration files, and only supported where Paludis can safely disambiguate this into cat/pkg.
cat/pkg: A simple package name with explicit category. This may be followed by suffixes, as described below.
=cat/pkg-1.23: A simple package name with an explicit category, package and version. Operators other than = are available, described below. This may be followed by suffixes.

In some places, either or both of cat and pkg may be *, which matches any category or package. This is not permitted where it would not make sense. To match any package in any category, use */*.

Suffixes

The cat/pkg and =cat/pkg-1.23 forms may be followed by zero or more optional suffixes, in the following order:

:slot: Match only in that slot.
::repo->repo: Repository requirements, described below.
::something: like ::->something, for all legal values of something.
[use] and [-use]: Match only if the named USE flag is enabled / disabled for this package. May be specified multiple times with different USE flag names.
[=1.23]: Match a particular version. Any operator described below can be used. May be extended to ranged dependencies, using either [=1.23|=1.24|=1.25] for an or dependency or [>=1.2&<2] for an and dependency.
[.key?]: Match only if the specified metadata key exists. key may be a key's raw name (e.g. DESCRIPTION, DEPEND) or a role prefixed with a dollar sign (e.g. $short_description, $build_dependencies). If the key's name is prefixed with ::, metadata from the repository rather than the package ID is checked. If the key is in (parens), matches masks by role, token or associated key (and (*) matches any mask).
[.key=value]: Match only if the specified metadata key has a particular exact value. Only works for simple values, sets and sequences, not spec trees and other complex compound keys. If < is used in place of =, for numeric values a less-than comparison is used, and for sets, sequences and spec trees, a match occurs if any member of the set or sequence is equal to the value. Similarly if > is used, for numeric values a greater-than comparison is used; it does not match for other types of values. As above, the key may be a raw name or a dollar-prefixed role name, and may be prefixed with :: for checking repository metadata.

Repository requirements are in the form to, from-> or ::from->to. The from may only be a repository name, and matches packages originally from that repository (so */*::myrepo-> finds installed packages that originated in myrepo. Valid forms for to are as follows:

repo: currently in this repository. Note that an installed package is no longer 'in' the repository whence it came; use a from specification for that.
repo?: could be installed to repo.
repo??: could be installed to repo, ignoring masks.
/path: installed at root /path (typically /).
/path?: could be installed to some installed repository with root path /path.
/path??: could be installed to some installed repository with root path /path, ignoring masks.

Operators

The following operators are recognised:

=: Exactly equal to.
<=: Less than or equal to.
<: Strictly less than.
>=: Greater than or equal to.
>: Strictly greater than.
~: Equal to, ignoring the package revision. If a package revision is specified, in addition the package must be of greater than or equal to this revision.
=*: Starting with this version, componentwise. The asterisk comes after the version part (=cat/pkg-1.2* or cat/pkg[=1.2*]).
~>: Greater than or equal to the version, and strictly less than the version with its one-before-least-significant digit part incremented, and its least significant digit part discarded. For example, ~>1.2.3 means >=1.2.3 and <1.3.