[Yum] Recursive dependency resolution

[Jim Bartus]

Is there a simple programmatic way to generate a list of every package 
that needs to be installed to meet the requirements of a given package? 
  Basically a dry run of what yum is made for but without being smart 
and ignoring those dependencies which are already met.

For instance "yum --what-would-be-needed-for php" would recursively go 
through and generate a list of all packages that php requires, and all 
the packages that those packages require, etc.

-jim