I believe there is an Ai command that uses the computer's minimum-town-size and maximum-town-size. I think the Ai tells the computer that the whole map is "his town", and that he should attack everything that is in his town. The computer will then also attack walls.
I never used the technique and only have vague memories of how it works. You may find something about it in an old post at the
Artificial Intelligence Scripting Forum. It dates back to the year 2002.
Ingo
My new double album, "Song Machine Vol. 1 and 2" with 24 of my songs is online now on Spotify, iTunes, Amazon and most other online services. Check it out, it's published under my name.