// If only we could "consume" the lists somehow... ;)
// We can work around this with immutability at least
public static SortedBy <int, Comp> GdpSortBy <Comp>(List <int> list, Named <Comparison <int>, Comp> comp)
{
List <int> listCopy = list.Select(item => item).ToList();
listCopy.Sort(comp.GetVal());
return(new SortedBy <int, Comp>(listCopy));
}
public static Proof <Equals <Length <Xs>, Succ <Succ <Zero> > > > LengthIsTwo <Xs>(Named <int, Length <Xs> > len)
{
if (len.GetVal() == 2)
{
return(Proof <Equals <Length <Xs>, Succ <Succ <Zero> > > > .Axiom());
}
return(null);
}
public static List <int> GdpMergeBy <Comp>(SortedBy <int, Comp> l1, SortedBy <int, Comp> l2, Named <Comparison <int>, Comp> comp)
{
return(MergeBy(l1.GetList(), l2.GetList(), comp.GetVal()));
}
public static Named <int, Length <Xs> > Len <Xs>(Named <List <int>, Xs> xs)
{
return(Named <int, Length <Xs> > .Defn(xs.GetVal().Count, new Length <Xs>()));
}