public static YieldTarget[] BuildYieldTargets(FuncDef func, CodeGen cg)
{
YieldLabelBuilder b = new YieldLabelBuilder(func, cg);
func.Walk(b);
return(b.topYields);
}
private void EmitGenerator(CodeGen ncg)
{
YieldTarget[] targets = YieldLabelBuilder.BuildYieldTargets(this, ncg);
Label[] jumpTable = new Label[yieldCount];
for (int i = 0; i < yieldCount; i++)
{
jumpTable[i] = targets[i].topBranchTarget;
}
ncg.yieldLabels = jumpTable;
ncg.PushTryBlock();
ncg.BeginExceptionBlock();
ncg.Emit(OpCodes.Ldarg_0);
ncg.EmitFieldGet(typeof(Generator), "location");
ncg.Emit(OpCodes.Switch, jumpTable);
// fall-through on first pass
// yield statements will insert the needed labels after their returns
body.Emit(ncg);
// fall-through is almost always possible in generators, so this
// is almost always needed
ncg.EmitReturnInGenerator(null);
// special handling for StopIteration thrown in body
ncg.BeginCatchBlock(typeof(StopIterationException));
ncg.EndExceptionBlock();
ncg.EmitReturnInGenerator(null);
ncg.PopTargets();
ncg.Finish();
}