public override Type Instantiate()
{
var subst = new Substitution();
foreach (var arg in Arguments.Where(arg => arg.RigidName == null))
{
subst.Bind(arg, new TypeVariable());
}
return(Inner.Perform(subst));
}
public void Unify(Type that, Substitution substitution)
{
try
{
Perform(substitution).SubstUnify(that.Perform(substitution), substitution);
}
catch (StackedException ex)
{
var sb = new StringBuilder("While trying to unify ");
PrettyPrint(ex.PrettyPrinter, sb, 0);
sb.Append(" with ");
that.PrettyPrint(ex.PrettyPrinter, sb, 0);
ex.Push(sb.ToString());
throw;
}
}
public override void DoUnify(Type var, Substitution substitution)
{
if (this == var)
{
return;
}
if (RigidName != null)
{
var.UnifyWithRigid(this, substitution);
}
else
{
if (var.FreeVariables().Contains(this))
{
throw OccursCheckException.Create(var.Perform(substitution), this.Perform(substitution));
}
substitution.Bind(this, var);
}
}
public override Type Perform(Substitution substitution)
{
return(new FunctionType(Argument.Perform(substitution), Result.Perform(substitution)));
}
public virtual void DoUnify(Type that, Substitution substitution)
{
throw TypeException.Create(Perform(substitution), that.Perform(substitution));
}