Run-Time Problem
Can't decide on nothing (P33)
    

Most problems are detected when Inform translates the source text, but this is one of the exceptions, a "run-time problem" which emerges only during play.


When we write a phrase 'To decide which K is ...', where K is a kind such as door or room, say, any use of 'decide on X' inside the definition of that phrase must result in X being the appropriate kind of thing. Here, X turned out to be nothing, which is not an object at all. While this can be used for something of kind object, it otherwise can't be used.