Esempio n. 1
0
		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();
		}