It's not that simple. There are actually very few situations where omitting the preposition changes the order of the direct and indirect object. In most cases, it just makes the sentence sound like nonsense. That's why you need to be able to specify the grammar (i.e. the pattern of the words used) and map this to an action. You can't do this in Adventuron or any of the old languages (Quill, PAW, DAAD etc.) that it's inspired by. Whereas you can do this in all modern IF languages (Adrift, Alan, Hugo, Inform, TADS, Quest etc.).
I have started using multi-word input for the first time and have decided that it's just too hard in Adventuron. Consider the following:
HIT
HIT dobject
HIT dobject WITH
HIT dobject iobject
HIT dobject WITH iobject
Only the last one is valid grammar. In the second one, you can imply that you are hitting the object with your hand or you can imply that if the relevant indirect object is held, then you hit the direct object with that. That's what old-school adventures with a two-word parser usually do.
However, in all cases, the direct object can be present or absent or a nonsense word. If present, it may be visible, but not accessible. It may be an animate object (non-player character) or an inanimate object. It may be in the player's inventory or worn or in a container or even the player himself/herself. The indirect object can be the same. For the action to make sense, the direct object should generally be an accessible object that is in the room, not in the player, and the indirect object should be carried by the player and not worn or in a container.
Now imagine testing for all these situations for every direct object that can be hit and every indirect object that can do the hitting, the code becomes unmanageable. That's why you need a grammar that can be specified in a standard library and supplemented or overridden. Then all you need to do is code the exceptions to the general case.
For me, I designed a small game in Inform 6 that was dependent on containers/supporters and multi-word input. As it's only a small game, I thought it would be easy to port to Adventuron. Now I'm tearing my hair out.