Issue description
The request is simple. Add a procedure for is [block] unbreakable (I mean test for the unbreakable property, there's a checkbox when you're creating a block).
This would mostly be used for:
if( not (is (get block at (targetx) (targety) (targetz) unbreakable))){
Destroy block at (targetx) (targety) (targetz) drop at (x) (y+1) (z)
}
that could be kind of neat. you could make a drill that checks for bedrock under itand stops mining, for example.