public static IType Infer(InferenceState initial, ITerm term)
{
var inference = new TypeInference(initial).Infer(term, out var result);
Console.WriteLine($"Final: {inference}");
var normalized = inference._state.Context.Normalize().Apply(result);
return(normalized);
}
public InferenceState Unify(out IImmutableList <InferenceState> states)
{
var state = this;
states = ImmutableList.Create(state);
while (state.Context.Any(e => e is IConstraint))
{
var prefix = state.Context.TakeWhile(e => !(e is IConstraint));
var eqAndSuffix = state.Context.SkipWhile(e => !(e is IConstraint));
if (eqAndSuffix.First() is IConstraint constraint)
{
state = new InferenceState(state.Fresh, constraint.Solve(prefix.ToImmutableList(), eqAndSuffix.Skip(1).ToImmutableList()));
}
else
{
throw new Exception("Should never get here: said there was a constraint, but then didn't find it.");
}
states = states.Add(state);
}
return(state);
}
private TypeInference(FreshVariableStream fresh, IImmutableList <IContextEntry> context)
{
this._state = new InferenceState(fresh, context);
}
private TypeInference(InferenceState inference)
{
this._state = inference;
}
private TypeInference()
{
this._state = new InferenceState(new FreshVariableStream(), ImmutableList <IContextEntry> .Empty);
}