/// <summary>
/// Creates an instantiation of the dispatch routine (or proto, which may
/// serve as one) supplied and augments it with the provided candidates.
/// It relies on being passed the instantiation of the dispatcher from the
/// last outer scope that had an instantiation, and we thus take its
/// candidates. This may or may not hold up in the long run; it works out
/// in the Perl 6-y "you can make a new instance from any object" sense
/// though, and seems more likely to get the closure semantics right than
/// any of the other approaches I've considered so far.
/// </summary>
/// <param name="TC"></param>
/// <param name="ToInstantiate"></param>
/// <param name="ExtraDispatchees"></param>
/// <returns></returns>
public static RakudoObject create_dispatch_and_add_candidates(ThreadContext TC, RakudoObject ToInstantiate, RakudoObject ExtraDispatchees)
{
// Make sure we got the right things.
var Source = ToInstantiate as RakudoCodeRef.Instance;
var AdditionalDispatchList = ExtraDispatchees as P6list.Instance;
if (Source == null || AdditionalDispatchList == null)
throw new Exception("create_dispatch_and_add_candidates expects a RakudoCodeRef and a P6list");
// Clone all but SC (since it's a new object and doesn't live in any
// SC yet) and dispatchees (which we want to munge).
var NewDispatch = new RakudoCodeRef.Instance(Source.STable);
NewDispatch.Body = Source.Body;
NewDispatch.CurrentContext = Source.CurrentContext;
NewDispatch.Handlers = Source.Handlers;
NewDispatch.OuterBlock = Source.OuterBlock;
NewDispatch.OuterForNextInvocation = Source.OuterForNextInvocation;
NewDispatch.Sig = Source.Sig;
NewDispatch.StaticLexPad = Source.StaticLexPad;
// Take existing candidates and add new ones.
NewDispatch.Dispatchees = new RakudoObject[Source.Dispatchees.Length + AdditionalDispatchList.Storage.Count];
var i = 0;
for (int j = 0; j < Source.Dispatchees.Length; j++)
NewDispatch.Dispatchees[i++] = Source.Dispatchees[j];
for (int j = 0; j < AdditionalDispatchList.Storage.Count; j++)
NewDispatch.Dispatchees[i++] = AdditionalDispatchList.Storage[j];
return NewDispatch;
}
/// <summary>
/// Initializes the context.
/// </summary>
/// <param name="StaticCodeObject"></param>
/// <param name="Caller"></param>
public Context(RakudoObject StaticCodeObject_Uncast, Context Caller, RakudoObject Capture)
{
// Set up static code object and caller pointers.
var StaticCodeObject = (RakudoCodeRef.Instance)StaticCodeObject_Uncast;
this.StaticCodeObject = StaticCodeObject;
this.Caller = Caller;
this.Capture = Capture;
// Static sub object should have this as the current
// context.
StaticCodeObject.CurrentContext = this;
// Lex pad should be an "instantiation" of the static one.
// Instantiating a lexpad creates a new dynamic instance of it
// from a static one, copying over the slot storage entries
// from the static one but sharing the slot mapping.
this.LexPad.SlotMapping = StaticCodeObject.StaticLexPad.SlotMapping;
this.LexPad.Storage = (RakudoObject[])StaticCodeObject.StaticLexPad.Storage.Clone();
// Set outer context.
if (StaticCodeObject.OuterForNextInvocation != null)
{
this.Outer = StaticCodeObject.OuterForNextInvocation;
}
else if (StaticCodeObject.OuterBlock.CurrentContext != null)
{
this.Outer = StaticCodeObject.OuterBlock.CurrentContext;
}
else
{
// Auto-close. In this we go setting up fake contexts
// that use the static lexpad until we find a real one.
var CurContext = this;
var OuterBlock = StaticCodeObject.OuterBlock;
while (OuterBlock != null)
{
// If we found a block with a context, we're done.
if (OuterBlock.CurrentContext != null)
{
CurContext.Outer = OuterBlock.CurrentContext;
break;
}
// Build the fake context.
var OuterContext = new Context();
OuterContext.StaticCodeObject = OuterBlock;
OuterContext.LexPad = OuterBlock.StaticLexPad;
// Link it.
CurContext.Outer = OuterContext;
// Step back one level.
CurContext = OuterContext;
OuterBlock = OuterBlock.OuterBlock;
}
}
}
/// <summary>
/// Creates a clone of the given code object, and makes its outer context
/// be set to the current context.
/// </summary>
/// <param name="TC"></param>
/// <param name="Block"></param>
/// <returns></returns>
public static RakudoObject new_closure(ThreadContext TC, RakudoCodeRef.Instance Block)
{
// Clone all but OuterForNextInvocation and SC (since it's a new
// object and doesn't live in any SC yet).
var NewBlock = new RakudoCodeRef.Instance(Block.STable);
NewBlock.Body = Block.Body;
NewBlock.CurrentContext = Block.CurrentContext;
NewBlock.Dispatchees = Block.Dispatchees;
NewBlock.Handlers = Block.Handlers;
NewBlock.OuterBlock = Block.OuterBlock;
NewBlock.Sig = Block.Sig;
NewBlock.StaticLexPad = Block.StaticLexPad;
// Set the outer for next invocation and return the cloned block.
NewBlock.OuterForNextInvocation = TC.CurrentContext;
return NewBlock;
}
/// <summary>
/// Creates a LeaveStackUnwinderException to target the given block
/// and exit it with the specified payload.
/// </summary>
/// <param name="TargetBlock"></param>
/// <param name="PayLoad"></param>
public LeaveStackUnwinderException(RakudoCodeRef.Instance TargetBlock, RakudoObject PayLoad)
{
this.TargetBlock = TargetBlock;
this.PayLoad = PayLoad;
}
/// <summary>
/// Sorts the candidates.
/// </summary>
/// <param name="Unsorted"></param>
/// <returns></returns>
private static RakudoCodeRef.Instance[] Sort(ThreadContext TC, RakudoObject[] Unsorted)
{
/* Allocate results array (just allocate it for worst case, which
* is no ties ever, so a null between all of them, and then space
* for the terminating null. */
var NumCandidates = Unsorted.Length;
var Result = new RakudoCodeRef.Instance[2 * NumCandidates + 1];
/* Create a node for each candidate in the graph. */
var Graph = new CandidateGraphNode[NumCandidates];
for (int i = 0; i < NumCandidates; i++)
{
Graph[i] = new CandidateGraphNode()
{
Candidate = (RakudoCodeRef.Instance)Unsorted[i],
Edges = new CandidateGraphNode[NumCandidates]
};
}
/* Now analyze type narrowness of the candidates relative to each other
* and create the edges. */
for (int i = 0; i < NumCandidates; i++) {
for (int j = 0; j < NumCandidates; j++) {
if (i == j)
continue;
if (IsNarrower(TC, Graph[i].Candidate, Graph[j].Candidate) != 0) {
Graph[i].Edges[Graph[i].EdgesOut] = Graph[j];
Graph[i].EdgesOut++;
Graph[j].EdgesIn++;
}
}
}
/* Perform the topological sort. */
int CandidatesToSort = NumCandidates;
int ResultPos = 0;
while (CandidatesToSort > 0)
{
int StartPoint = ResultPos;
/* Find any nodes that have no incoming edges and add them to
* results. */
for (int i = 0; i < NumCandidates; i++) {
if (Graph[i].EdgesIn == 0) {
/* Add to results. */
Result[ResultPos] = Graph[i].Candidate;
Graph[i].Candidate = null;
ResultPos++;
CandidatesToSort--;
Graph[i].EdgesIn = EDGE_REMOVAL_TODO;
}
}
if (StartPoint == ResultPos) {
throw new Exception("Circularity detected in multi sub types.");
}
/* Now we need to decrement edges in counts for things that had
* edges from candidates we added here. */
for (int i = 0; i < NumCandidates; i++) {
if (Graph[i].EdgesIn == EDGE_REMOVAL_TODO) {
for (int j = 0; j < Graph[i].EdgesOut; j++)
Graph[i].Edges[j].EdgesIn--;
Graph[i].EdgesIn = EDGE_REMOVED;
}
}
/* This is end of a tied group, so leave a gap. */
ResultPos++;
}
return Result;
}
