/**
* Check that the expression has enough numbers and variables to fit the
* requirements of the operators and functions, also check
* for only 1 result stored at the end of the evaluation.
*/
internal void Validate(List <Token> rpn)
{
/*-
* Thanks to Norman Ramsey:
* http://http://stackoverflow.com/questions/789847/postfix-notation-validation
*/
// each push on to this stack is a new function scope, with the value of each
// layer on the stack being the count of the number of parameters in that scope
Stack <int> stack = new Stack <int>();
// push the 'global' scope
stack.Push(0);
foreach (Token token in rpn)
{
switch (token.type)
{
case TokenType.UNARY_OPERATOR:
if (stack.Peek() < 1)
{
throw new ExpressionException("Missing parameter(s) for operator " + token);
}
break;
case TokenType.OPERATOR:
if (stack.Peek() < 2)
{
throw new ExpressionException("Missing parameter(s) for operator " + token);
}
// pop the operator's 2 parameters and add the result
int v = stack.Pop();
stack.Push(v - 2 + 1);
break;
case TokenType.FUNCTION:
bool isMap = false, isReduce = false;
string s = token.surface;
if (s[0] == '$')
{
isMap = true;
s = s.Substring(1);
}
if (s[0] == '@')
{
isReduce = true;
s = s.Substring(1);
}
if (!functions.TryGetValue(s, out LazyFunction tmplazyfun))
{
throw new UnknownFunctionInExpressionException(string.Format("Unknown function: {0}", s), s);
}
LazyFunction f = tmplazyfun;
if (f == null)
{
throw new ExpressionException("Unknown function '" + token + "' at position " + (token.pos + 1));
}
int numParams = stack.Pop();
if (isReduce)
{
numParams++;
}
if (!f.NumParamsVaries())
{
if (numParams != f.NumParams)
{
throw new ExpressionException("Function " + token + " expected " + f.NumParams + " parameters, got " + numParams);
}
// TODO check numero parametri della funzione mappata
if (isMap && numParams == 0)
{
throw new ExpressionException("Mapping requires at least one parameter, calling function " + token);
}
// TODO check numero parametri della funzione ridotta
if (isReduce && numParams < 2)
{
throw new ExpressionException("Reduce requires at least two parameters, calling function " + token);
}
}
if (stack.Count <= 0)
{
throw new ExpressionException("Too many function calls, maximum scope exceeded");
}
// push the result of the function
int val = stack.Pop();
stack.Push(val + 1);
break;
case TokenType.OPEN_PAREN:
stack.Push(0);
break;
case TokenType.OBJPATH:
break;
default:
val = stack.Pop();
stack.Push(val + 1);
break;
}
}
if (stack.Count > 1)
{
throw new ExpressionException("Too many unhandled function parameter lists");
}
else if (stack.Peek() > 1)
{
throw new ExpressionException("Too many numbers or variables");
}
else if (stack.Peek() < 1)
{
throw new ExpressionException("Empty expression");
}
}
private LazyNumber LazyEval(string expression)
{
if (string.IsNullOrEmpty(expression))
{
throw new ExpressionException("Empty expression");
}
Stack <LazyNumber> stack = new Stack <LazyNumber>();
foreach (Token token in GetRPN(expression))
{
switch (token.type)
{
case TokenType.UNARY_OPERATOR:
LazyNumber value = stack.Pop();
stack.Push(operators[token.surface].Eval(value, null));
break;
case TokenType.OPERATOR:
LazyNumber v2 = stack.Pop();
LazyNumber v1 = stack.Pop();
stack.Push(operators[token.surface].Eval(v1, v2));
break;
case TokenType.VARIABLE:
LazyNumber lazyNumber;
if (variables.ContainsKey(token.surface))
{
lazyNumber = new FunLazyNumberS(() => variables[token.surface]);
}
else
{
if (vararrays.ContainsKey(token.surface))
{
lazyNumber = new FunLazyNumberA(() => vararrays[token.surface]);
}
else
{
if (stringVariables.ContainsKey(token.surface))
{
lazyNumber = new FunLazyString(() => stringVariables[token.surface]);
}
else
{
throw new UnknownVariableInExpressionException("Unknown variable: " + token.ToString(), token.ToString());
}
}
}
stack.Push(lazyNumber);
break;
case TokenType.OBJPATH:
if (!string.IsNullOrEmpty(token.surface))
{
LazyNumber avar = stack.Peek();
if (avar is FunLazyString)
{
var lazyjson = new FunLazyJSON((FunLazyString)avar)
{
ObjectPath = token.surface
};
stack.Pop();
stack.Push(lazyjson);
}
else
{
throw new ExpressionException("Object path set to a variable that is not a JSON object");
}
}
else
{
throw new ExpressionException("Empty or invalid object path");
}
break;
case TokenType.FUNCTION:
bool isMap = false, isReduce = false;
string s = token.surface;
if (s[0] == MapChar)
{
s = s.Substring(1);
isMap = true;
}
if (s[0] == ReduceChar)
{
s = s.Substring(1);
isReduce = true;
}
LazyFunction f = functions[s];
List <LazyNumber> p = new List <LazyNumber>(
!f.NumParamsVaries() ? f.NumParams : 0);
// pop parameters off the stack until we hit the start of
// this function's parameter list
while (!stack.IsEmpty() && stack.Peek() != PARAMS_START)
{
p.Insert(0, stack.Pop());
}
if (stack.Peek() == PARAMS_START)
{
stack.Pop();
}
LazyNumber fResult;
if (isMap)
{
fResult = new FunLazyNumberA(() =>
{
double[] vals = p[0].EvalArray();
if (vals.Length == 0)
{
return(new double[0]);
}
double[] res = new double[vals.Length];
int i = 0;
foreach (double val in vals)
{
p[0] = new FunLazyNumberS(() => val);
res[i++] = f.LazyEval(p).Eval();
}
return(res);
});
}
else
{
if (isReduce)
{
fResult = new FunLazyNumberS(() =>
{
double[] vals = p[0].EvalArray();
if (vals.Length == 0)
{
return(0.0D);
}
if (vals.Length == 1)
{
return(vals[0]);
}
double res = 0.0D;
List <LazyNumber> pred = new List <LazyNumber>(p.Count + 1)
{ // collection initialization ... ugly ....:)
null,
null
};
if (p.Count > 1)
{
pred.AddRange(p.GetRange(1, p.Count - 1));
}
pred[0] = new FunLazyNumberS(() => vals[0]);
pred[1] = new FunLazyNumberS(() => vals[1]);
res = f.LazyEval(pred).Eval();
for (int i = 2; i < vals.Length; i++)
{
pred[0] = new FunLazyNumberS(() => res);
pred[1] = new FunLazyNumberS(() => vals[i]);
res = f.LazyEval(pred).Eval();
}
return(res);
});
}
else
{
fResult = f.LazyEval(p);
}
}
stack.Push(fResult);
break;
case TokenType.OPEN_PAREN:
stack.Push(PARAMS_START);
break;
case TokenType.LITERAL:
stack.Push(new FunLazyNumberS(() => StoD(token.surface)));
break;
case TokenType.STRINGPARAM:
FunLazyString tmpNumber = new FunLazyString(() => token.surface);
stack.Push(tmpNumber);
break;
case TokenType.HEX_LITERAL:
double hexd = double.NaN;
try
{
hexd = (double)Convert.ToInt64(token.surface, 16);
}
catch (Exception) { } // no need to worry, just NaN
stack.Push(new FunLazyNumberS(() => hexd));
break;
}
}
return(stack.Pop());
}