* In def 2.5, they say the denotation of an e-type constant α wrt a discourse possibility `(r, g, w)` is whatever object the world `w` associates with α. Since we don't have worlds, this will just be an object. * They say the denotation of a predicate is whatever extension the world `w` associates with the predicate. Since we don't have worlds, this will just be an extension. * They say the denotation of a variable is the object which the store `g` assigns to the index that the assignment function `r` assigns to the variable. In other words, if the variable is `'x'`, its denotation wrt `(r, g, w)` is `g[r['x']]`. We're going to keep all of that, except dropping the worlds. And instead of talking about "\[[expression]] in discourse possibility `(r, g, w)`," we'll just talk about "\[[expression]]" and let that be a monadic object, implemented in part by a function that takes `(r, g)` as an argument. More specifically, "\[[expression]]" will be a set of 'a discourse possibility monads, where 'a is the appropriate type for "expression," and the discourse possibility monads are themselves state monads where `(r, g)` is the state that gets updated. Those are implemented as functions from `(r, g)` to `(a, r', g')`, where `a` is a value of type `'a`, and `r', g'` are possibly altered assignment functions and stores. * In def 2.7, GS&V talk about an operation that takes an existing set of discourse possibilities, and extends each member in the set by allocating a new location in the store, and assigning a variable `'x'` to that location, which holds some object `d` from the domain. It will be useful to have a shorthand way of referring to this operation: let newpeg_and_bind (variable : char) (d : entity) = fun ((r, g) : assignment * store) -> let newindex = List.length g (* first we store d at index newindex in g, which is at the very end *) (* the following line achieves that in a simple but very inefficient way *) in let g' = List.append g [d] (* next we assign 'x' to location newindex *) in let r' = fun variable' -> if variable' = variable then newindex else r variable' (* the reason for returning a triple with () in first position will emerge *) in ((), r',g')