The ability to set rules in custom maps (scripting and triggers)

One thing that I really enjoy doing when creating my custom maps is setting rules for the player to follow as part of the challenge. If we could get certain restrictions to be able to build into the map that would be fantastic.
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Some examples of past challenges maps I have created include:
- Not being able to stack platforms/stairs past three levels.
- Not being able to build over a certain height.
- Not being able to build under a certain height.
- Not being able to build on land that is a certain height.
- Not being able to build in a set area.
- Not being able to terraform the terrain.

Some ideas of challenges I'd like to create, but can't.
- Being able to change drought settings and trigger droughts on certain triggers.
- Being able to adjust the output of water source blocks according to external triggers.
- Being able to add prebuilt buildings and restrict the building of certain buildings (see my other suggestions)