/// <summary>
/// Looks up the state associated with the specified parameter expression by scanning the scoped symbol table, starting from the current scope.
/// </summary>
/// <param name="parameter">Parameter expression to look up.</param>
/// <param name="state">State associated with the specified parameter expression.</param>
/// <returns>true if the symbol was found; otherwise, false.</returns>
protected bool TryLookup(ParameterExpression parameter, out TState state)
{
if (parameter == null)
{
throw new ArgumentNullException(nameof(parameter));
}
if (_symbolTable.TryLookup(parameter, out Indexed <Indexed <TState> > value))
{
state = value.Value.Value;
return(true);
}
state = default;
return(false);
}
public void ScopedSymbolTable_Basics()
{
var res = default(Indexed <Indexed <string> >);
var sst = new ScopedSymbolTable <string, string>
{
{ "glb", "val" }
};
var assertGlobal = new Action(() =>
{
Assert.IsTrue(sst.TryLookup("glb", out res));
Assert.AreEqual(-1, res.Index);
Assert.AreEqual(0, res.Value.Index);
Assert.AreEqual("val", res.Value.Value);
Assert.IsFalse(sst.TryLookup("blg", out res));
});
assertGlobal();
AssertPushPop(sst,
() =>
{
assertGlobal();
Assert.IsFalse(sst.TryLookup("bar", out res));
},
() =>
{
sst.Add("bar", "foo");
sst.Add("baz", "qux");
AssertPushPop(sst,
() =>
{
assertGlobal();
Assert.IsTrue(sst.TryLookup("bar", out res));
Assert.AreEqual(0, res.Index);
Assert.AreEqual(0, res.Value.Index);
Assert.AreEqual("foo", res.Value.Value);
Assert.IsTrue(sst.TryLookup("baz", out res));
Assert.AreEqual(0, res.Index);
Assert.AreEqual(1, res.Value.Index);
Assert.AreEqual("qux", res.Value.Value);
},
() =>
{
sst.Add("foo", "bar");
sst.Add("bar", "qux");
AssertPushPop(sst,
() =>
{
assertGlobal();
Assert.IsTrue(sst.TryLookup("foo", out res));
Assert.AreEqual(0, res.Index);
Assert.AreEqual(0, res.Value.Index);
Assert.AreEqual("bar", res.Value.Value);
Assert.IsTrue(sst.TryLookup("bar", out res));
Assert.AreEqual(0, res.Index);
Assert.AreEqual(1, res.Value.Index);
Assert.AreEqual("qux", res.Value.Value);
Assert.IsTrue(sst.TryLookup("baz", out res));
Assert.AreEqual(1, res.Index);
Assert.AreEqual(1, res.Value.Index);
Assert.AreEqual("qux", res.Value.Value);
},
() =>
{
sst.Add("qux", "baz");
AssertPushPop(sst,
() =>
{
assertGlobal();
Assert.IsTrue(sst.TryLookup("qux", out res));
Assert.AreEqual(0, res.Index);
Assert.AreEqual(0, res.Value.Index);
Assert.AreEqual("baz", res.Value.Value);
Assert.IsTrue(sst.TryLookup("foo", out res));
Assert.AreEqual(1, res.Index);
Assert.AreEqual(0, res.Value.Index);
Assert.AreEqual("bar", res.Value.Value);
Assert.IsTrue(sst.TryLookup("bar", out res));
Assert.AreEqual(1, res.Index);
Assert.AreEqual(1, res.Value.Index);
Assert.AreEqual("qux", res.Value.Value);
Assert.IsTrue(sst.TryLookup("baz", out res));
Assert.AreEqual(2, res.Index);
Assert.AreEqual(1, res.Value.Index);
Assert.AreEqual("qux", res.Value.Value);
},
() =>
{
// NOTE: The test method pushes a frame before entering, so we're off by 1 for the outer indices.
Assert.IsNotNull(((IEnumerable)sst).GetEnumerator());
var symbols = sst.SelectMany(ist => ist.Value, (o, i) => (Outer: o.Index, Inner: i.Index, Symbol: i.Value.Key, i.Value.Value)).ToArray();
Assert.IsTrue(symbols.SequenceEqual(new[]
{
(Outer: 1, Inner: 0, Symbol: "qux", Value: "baz"),
(Outer: 2, Inner: 0, Symbol: "foo", Value: "bar"),
(Outer: 2, Inner: 1, Symbol: "bar", Value: "qux"),
(Outer: 3, Inner: 0, Symbol: "bar", Value: "foo"),
(Outer: 3, Inner: 1, Symbol: "baz", Value: "qux"),
(Outer: -1, Inner: 0, Symbol: "glb", Value: "val"),
}));
