public override void Compile(ByteCode bc)
{
//for var_1, ···, var_n in explist do block end
bc.PushSourceRef(m_RefFor);
Loop L = new Loop()
{
Scope = m_StackFrame
};
bc.LoopTracker.Loops.Push(L);
// get iterator tuple
m_RValues.Compile(bc);
// prepares iterator tuple - stack : iterator-tuple
bc.Emit_IterPrep();
// loop start - stack : iterator-tuple
int start = bc.GetJumpPointForNextInstruction();
bc.Emit_Enter(m_StackFrame);
// expand the tuple - stack : iterator-tuple, f, var, s
bc.Emit_ExpTuple(0);
// calls f(s, var) - stack : iterator-tuple, iteration result
bc.Emit_Call(2, "for..in");
// perform assignment of iteration result- stack : iterator-tuple, iteration result
for (int i = 0; i < m_NameExps.Length; i++)
m_NameExps[i].CompileAssignment(bc, 0, i);
// pops - stack : iterator-tuple
bc.Emit_Pop();
// repushes the main iterator var - stack : iterator-tuple, main-iterator-var
bc.Emit_Load(m_Names[0]);
// updates the iterator tuple - stack : iterator-tuple, main-iterator-var
bc.Emit_IterUpd();
// checks head, jumps if nil - stack : iterator-tuple, main-iterator-var
var endjump = bc.Emit_Jump(OpCode.JNil, -1);
// executes the stuff - stack : iterator-tuple
m_Block.Compile(bc);
bc.PopSourceRef();
bc.PushSourceRef(m_RefEnd);
// loop back again - stack : iterator-tuple
bc.Emit_Leave(m_StackFrame);
bc.Emit_Jump(OpCode.Jump, start);
bc.LoopTracker.Loops.Pop();
int exitpointLoopExit = bc.GetJumpPointForNextInstruction();
bc.Emit_Leave(m_StackFrame);
int exitpointBreaks = bc.GetJumpPointForNextInstruction();
bc.Emit_Pop();
foreach (Instruction i in L.BreakJumps)
i.NumVal = exitpointBreaks;
endjump.NumVal = exitpointLoopExit;
bc.PopSourceRef();
}