public static Func <IEnumerable <IEnumerable <RHS_ElemT> >, MotherT> MkFun <RHS_ElemT>(Func <RHS_ElemT, ElemT> elemFunc, int len_outer, int len_inner)
{
// can't really determine wheter indexer property is implemented from the type system
MethodInfo setterMI = typeof(MotherT).GetMethod("set_Item", new [] { typeof(int), typeof(int), typeof(ElemT) });
Func <IEnumerable <IEnumerable <RHS_ElemT> >, MotherT> F = (L_in) =>
{
var R = new MotherT();
object obR = RuntimeHelpers.GetObjectValue(R); // todo only for value types - how is this different from casting to (object) ??
var rator_outer = L_in.GetEnumerator();
for (int i_outer = 0; i_outer < len_outer; i_outer++)
{
if (!rator_outer.MoveNext())
{
throw new RHS_Shape_Exception(); // <- these don't fly properly they are somehow
}
var rator_inner = rator_outer.Current.GetEnumerator();
for (int i_inner = 0; i_inner < len_inner; i_inner++)
{
if (!rator_inner.MoveNext())
{
throw new RHS_Shape_Exception();
}
setterMI.Invoke(obR, new object[] { i_outer, i_inner, elemFunc(rator_inner.Current) });
}
}
return((MotherT)obR);
};
return(F);
}
/*
* the sole reason for this indirection is that c# can't translate member calls on open generic types
* e.g. i need T in: List<T>.Count() bound here
* (introduce RHS_ElemT as generic variable, only to specialize it the constructor )
* ... there probably is a less convoluted way of doing this
*/
public static Func <IEnumerable <RHS_ElemT>, LHS_ElemT[]> MkFunc <RHS_ElemT>(Func <RHS_ElemT, LHS_ElemT> elemFunc)
{
Func <IEnumerable <RHS_ElemT>, LHS_ElemT[]> F = (L_in) =>
{
int len = L_in.Count();
var R = new LHS_ElemT[len];
var rator = L_in.GetEnumerator();
for (int i = 0; i < len; i++)
{
rator.MoveNext();
R[i] = elemFunc(rator.Current);
}
return(R);
};
return(F);
}
public static Func <IEnumerable <RHS_ElemT>, MotherT> MkFun <RHS_ElemT>(Func <RHS_ElemT, ElemT> elemFunc, int len)
{
// can't really determine wheter indexer property is implemented from the type system
MethodInfo setterMI = typeof(MotherT).GetProperty("Item").GetSetMethod();
Func <IEnumerable <RHS_ElemT>, MotherT> F = (L_in) =>
{
var R = new MotherT();
object obR = RuntimeHelpers.GetObjectValue(R); // todo only for value types - how is this different from casting to (object) ??
var rator = L_in.GetEnumerator();
for (int i = 0; i < len; i++)
{
if (!rator.MoveNext())
{
throw new RHS_Shape_Exception();
}
setterMI.Invoke(obR, new object[] { i, elemFunc(rator.Current) });
}
return((MotherT)obR);
};
return(F);
}
