ok well first off their is software that works for slackware only; this is one of them .
slpkg :
https://slackbuilds.org/repository/14.2/system/slpkg/?search=slpkg
( not to be confused with slackpkg )
so you run the slackbuild to create slpkg package, install it and tweak mirrors for repo
ok lets say i want a video editor maybe cinelerra ? lets search
# slpkg -F cinelerra
Packages with name matching [ cinelerra ]
+===============================================================
| Repository Package Size
+===============================================================
sbo cinelerra-2.3 0 K
Found summary
================================================================ttotal found 1 packages in 1 repositories.
ok now let me see what the dependencies are going to be :
bash-5.0# slpkg -t sbo cinelerra
Resolving dependencies... Done
+=================================
| Package cinelerra dependencies :
+=================================
\
+---[ Tree of dependencies ]
|
+--1: faac
|
+--2: faad2
|
+--3: imlib2
|
+--4: libavc1394
|
+--5: libdv
|
+--6: libiec61883
|
+--7: mjpegtools
|
+--8: lame
|
+--9: x264
bash-5.0#
on my output the above 1-9 are in green, which tells me i have them installed. It can also print out nice graph in image form see attached.