The most basic type of dependency is the require dependency. These dependencies are typically used to express functional dependencies such as libraries, or interpreters such as Python or Perl.
If a package A@1.0 contains a require dependency on package B@2, then if A@1.0 is installed, the B package at version 2 or higher must also be installed. This acceptance of higher versioned packages reflects the implicit expectation of binary compatibility in newer versions of existing packages.
If any version of the package named in the depend action is acceptable, you can omit the version portion of the specified FMRI.
An example require dependency is:
depend fmri=pkg:/system/library type=require