spawning units/merchants/sieges
Can't spawn sieges anymore. However, spawning
armies is essentially equivalent. If that's researched well enough, that would be possible. I personally don't have
quite the knowledge required to figure out what the hell the army structures are about, though.
I sort of wrote that force script in the first place, but it was basically a minorly modified oneliner by Quietust that I gave some arguments. I fully understand how it works
now, so I can maintain it, but updating force siege is outside the scope of the force script (though not outside the scope of DFHack or even my personal scope of what-I-want-to-do).
What are scripts in a DF context, and how would one learn to make them?
In general, they seem to access things in the games files or the exe that are difficult to modify/inspect. DFhack runs Lua scripts, I think. The wiki's got a few articles on DFhack and there are numerous Lua tutorials out there. You'd probably be able to find support on Bay12 proper in the Programming Help thread or the DF modding board.
DFHack has docs for the Lua API and
XML files detailing all the structures that DFHack (and thus its Lua bindings) can access. The DFHack thread under utilities and 3rd party applications is probably the best place to get help for DFHack-specific help (I.E. stuff regarding dwarf fortress structures and interacting with Dwarf Fortress)--the programming thread in the lower boards is the best place to get started around here, though I would personally just, like, go everywhere if you really want to get into it.
It's not really the .exe that's modified, btw--it's the memory at runtime, like Cheat Engine. DFHack can also run compiled C++ plugins and Ruby scripts.