public void EvaluateNodeWritesToTopFrameStack()
{
// Create context
var context = CreateContext();
var symbol = SymbolTable.Symbols.TextToSymbol("id");
// Insert value in lower frame
context.SetLocalValue(symbol, 24);
context.PushFrame("x", null, context.CurrentFrame);
// Insert value in top frame
context.SetLocalValue(symbol, 42);
context.PushFrame("y", null, context.CurrentFrame);
context.Data.Push(100);
// Try evaluating
var sut = new LocalIdentifierNode();
var token = new TestToken(symbol);
sut.Init(null, new ParseTreeNode(token));
sut.EvaluateNode(context, AstMode.Write);
var actual = context.CurrentFrame.Values[symbol];
Assert.That(actual, Is.EqualTo(100));
// Check that parent value is untouched. This is what differentiate LocalIdentifierNode from IdentifierNode
Assert.That(context.CurrentFrame.Parent.Values[symbol], Is.EqualTo(42));
}
public void EvaluateNodeReadsFromTopMostSymbolInFrameStack()
{
// Create context
var context = CreateContext();
var symbol = SymbolTable.Symbols.TextToSymbol("id");
// Insert value in lower frame
context.SetLocalValue(symbol, 24);
context.PushFrame("x", null, context.CurrentFrame);
// Insert value in top frame
context.SetLocalValue(symbol, 42);
context.PushFrame("y", null, context.CurrentFrame);
// Try evaluating
var sut = new LocalIdentifierNode();
var token = new TestToken(symbol);
sut.Init(null, new ParseTreeNode(token));
sut.EvaluateNode(context, AstMode.Read);
var actual = context.LastResult;
Assert.That(actual, Is.EqualTo(42));
}