Compare Stackage snapshots

$forall (pkgname, VersionChange verChange, versionDiff) <- toVersionedDiffList snapDiff $case verChange $of This oldVersion

#{name1}	#{name2}
#{pkgname}	#{oldVersion} $of That newVersion	#{pkgname}	#{newVersion} $of These oldVersion newVersion $maybe (common, old, new) <- versionDiff	#{pkgname}	#{common}# #{old} → #{common}# #{new} $nothing	#{pkgname}	#{oldVersion} → #{newVersion}