I may have this thing cracked. I finally got at least a very rough prototype worked out.
The trick was something very simple (naturally). I was trying to just work with the hspeed of my player object and pass that to the movable objects. It didn't seem to pass hspeed as a negative, though (for "left" direction). I could move it to the right, fine - no matter how I collided with the object.
The key was, in a collision event, to pass the direction of my player object to the movables. And this is done by calling other.direction (simple, I know).
I also use two .libs, Ultima Actions v3 and Platform Basic 2.0 - one of them has a decent solids code and the other a rough kinetic collision event (probably just a bounce event with some kind of damping, but saves me a headache).
There are two major errors, and I may end up going to the community for help:
1. If you push a movable object against a wall, when it bounces off the wall it will penetrate the main character's collision. They're both solids, so this shouldn't happen, but I think it has to do with using the jump to position command - I may have to try and find another way to move the objects.
2. If one movable object falls on top of another (or sometimes while pushing several of them together) one of them will pop through the floor. Again, probably something to do with jumping to position. I can fix some of that by playing with the vspeed, but this won't work if the object is in the air (setting the vspeed to 0 in those cases makes the object hang, of course).
I'm also not happy with the way my wall collisions function right now (a simple bounce, but then the character shakes if you keep pressing into it), but that's not rightly a bug.
Hopefully people aren't getting bored with my worklogs. This is a good way to keep track of my progress and the various things I've tried. I hope it might also help other people using gamemaker.
Get used to it, though. I haven't even begun to incorporate the graphics or sound or menu functionality.
And while I'm on the subject, I wanted to talk directly about Gamemaker itself.
Go to Yoyogames' site.
Look around a bit.
It sucks. They barely tell you about the software. It looks like a generic spam or placeholder site.
The original Gamemaker site is still up, but isn't being updated. The tutorials absolutely suck. There is a message about v7 and a whole bunch of new developments for March. Version 7 came out at the end of February.
And here we are in April and the Yoyogames site hasn't changed. They haven't migrated the forums or released new extensions or done much of anything. They don't even have a news feed to tell people what's coming or if they're doing any work.
The creator explained his decision to sell as a way to keep development going since he no longer had the time. That's reasonable. But now there's not even a peep from the new guys.
Not the way to build a community.
64digits is a good way to organize a community, if you can wade through the endless Naruto references and adolescent depression.
Don't forget about April's Round Table.