/// <summary>
/// Pushes a new evaluation frame against the specified node.
/// </summary>
/// <param name="node">Node.</param>
/// <param name="childCounter">Child counter.</param>
public void Push(AstNode node, int childCounter = 0)
{
var frame = new EvaluationFrame(node, (cur_scope == null) ? 0 :
ShouldIntroduceScope(node) ? stack.Count : cur_scope.ScopeFramePointer,
childCounter, this);
frames.Add(frame);
if(node is CallExpression)
cur_scope = frame;
}
/// <summary>
/// Pushes a new evaluation frame without introducing a new scope.
/// </summary>
/// <param name="node">Node.</param>
/// <param name="childCounter">Child counter.</param>
public void PushWithoutScope(AstNode node, int childCounter = 0)
{
var frame = new EvaluationFrame(node, (cur_scope != null) ? cur_scope.ScopeFramePointer : 0, childCounter, this);
frames.Add(frame);
}
/// <summary>
/// Pops the top evalution frame.
/// </summary>
/// <returns>The removed evaluation frame.</returns>
public EvaluationFrame Pop()
{
if(frames.Count == 0)
throw new InvalidOperationException();
var tmp = frames[frames.Count - 1];
frames.RemoveAt(frames.Count - 1);
if(tmp.TargetNode is ScopeStatement) //一つ上のスコープに対応する評価フレームをセットする
cur_scope = ((IEnumerable<EvaluationFrame>)frames).Reverse().FirstOrDefault(x => x.TargetNode is CallExpression);
return tmp;
}