Represents a proof context (ML type Proof.context) in the ML context.

An instance of this class is merely a thin wrapper around an MLValue, that is, the context is never transferred to the Scala process (which would not be possible because a context cannot be serialized). However, by having this wrapper, a context can be treated as if it were a Scala object (as opposed to a value stored in the Isabelle process).

This class is compatible with the MLValue mechanism. That is, from a Context context, we can create an MLValueContext by MLValue(context), and we can get a Context back using .retrieve/.retrieveNow. This conversion is needed if we want to pass contexts to (or return contexts from) ML functions compiled using MLValue.compileFunction. For example, say countTheorems : Proof.context -> int is an ML function, then we can compile it using

val countTheorems = MLValue.compileFunction[Context,Int]("countTheorems")

and invoke it as

val num : Int = countTheorems(context).retrieveNow  // where context : Context

Make sure to import de.unruh.isabelle.pure.Implicits._ for the MLValue-related functions to work.

Not that contexts (being MLValues), are internally futures and may still fail. To make sure a Context actually contains a value, use, e.g., Context.force.