/// <summary>
/// Indexer handling reading adn writing to the registry
/// </summary>
/// <param name="key">target variable</param>
/// <returns>variable value</returns>
public IExpression this[VariableExpression key]
{
get { return registry.ContainsKey(key.Value) ? registry[key.Value] : key; }
set
{
if (registry.ContainsKey(key.Value))
{
if(registry[key.Value].Value==value.Value)
return;
throw new Exception("registry values missmatch " + value + " + " +registry[key.Value]);
}
registry.Add(key.Value, value);
}
}
/// <summary>
/// Consume next token
/// </summary>
/// <param name="l">the lexer</param>
/// <param name="expr">output expression</param>
static void EvalToken(ref Lexer l, out IExpression expr)
{
switch (l.Token)
{
case Token.QuotedString:
case Token.Float:
case Token.Int:
case Token.False:
case Token.True:
if (FuncStack.Count == 0)
{
expr = new ValueExpression(l.Value);
return;
}
ParamStack.Peek().Add(new ValueExpression(l.Value));
break;
case Token.Variable:
if (FuncStack.Count == 0)
{
expr = new VariableExpression(l.Value);
return;
}
ParamStack.Peek().Add(new VariableExpression(l.Value));
break;
case Token.Function:
FuncStack.Push(l.Value);
break;
case Token.LeftBrace:
ParamStack.Push(new List<IExpression>());
break;
case Token.RightBrace:
if(FuncStack.Count == 1)
{
var p = ParamStack.Pop().ToArray();
expr = new FunctionExpression(FuncStack.Pop(), p);
return;
}
var param = ParamStack.Pop().ToArray();
ParamStack.Peek().Add(new FunctionExpression(FuncStack.Pop(),param));
break;
case Token.Comma:
case Token.Dot:
case Token.Space:
break;
default:
throw new ArgumentOutOfRangeException();
}
expr = null;
}
