[MacPorts] #16336: Allow multiple ports to satisfy a single dependency

[MacPorts]

#16336: Allow multiple ports to satisfy a single dependency
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 Reporter:  rhwood at macports.org  |       Owner:  macports-tickets at lists.macosforge.org
     Type:  enhancement          |      Status:  new                                  
 Priority:  Normal               |   Milestone:                                       
Component:  ports                |     Version:  1.6.0                                
 Keywords:                       |  
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 Currently there is no mechanism to specify that multiple ports may satisfy
 a single dependency requirement. It would be nice to be able to do so. I
 can think of two ways this can be done:

  OR dependencies::
    Allow dependencies to be specified in the following
 fashion:[[BR]]{{{port:able|baker|charlie}}}[[BR]]where the pipe is used to
 separate one or more ports that may satisfy a single dependency. The first
 port would be used if none of the ports are installed. There should be no
 limit to the number of pipes, nor should there be any requirement that any
 pipes be used (ie, no pipes = no alternate dependencies). This should also
 wotk with ''bin:'' and ''path:'' type dependencies.
  "provides" capability in ports::
    Use a "provides" key to specify that a port satisfies a particular
 requirement. Use the name of the port if a provides keyword is not
 specified. For example, if port '''able-devel''' specifies that it {{{
 provides able }}} then port '''able-devel''' would be able satisfy the
 dependency {{{ port:able }}} in another port, without that other port
 having to be aware of port '''able-devel'''

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Ticket URL: <http://trac.macports.org/ticket/16336>
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