Relation

A Relation is a binary comparison operation on a Name (string) and an Edition (epoch, version, release)

It is used to express dependencies between Resolvables.

The formal relation expression is

<name> [<op> <edition>]

Each Resolvable provides a non-empty set of Name, Edition combinations (a Spec).

A Relation can be verified against each member of this set. It matches if the Names are equal and the comparison of the Edition evaluates to true.

Examples:
Resolvable provides Name Foo with Edition 1.42-7
This matches the following Relations Foo == 1.42-7 (complete match)
Foo == 1.42 (Release omitted, treated as any)
Foo < 1.43
Foo >= 1.37
Foo != 8.15
Foo

The last relation does not specify an operator or an edition. In this case, both are treated as any. So the Relation Foo matches any Resolvable which provides the name Foo in whatever version.

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Last edit in Trac '11/23/05 10:50:11' by 'kkaempf'

Libzypp/Design/Relation

Relation