IValue Parse(string aExpression)
{
aExpression = aExpression.Trim();
int index = aExpression.IndexOf('(');
while (index >= 0)
{
SubstitudeBracket(ref aExpression, index);
index = aExpression.IndexOf('(');
}
if (aExpression.Contains(','))
{
string[] parts = aExpression.Split(',');
List<IValue> exp = new List<IValue>(parts.Length);
for (int i = 0; i < parts.Length; i++)
{
string s = parts[i].Trim();
if (!string.IsNullOrEmpty(s))
exp.Add(Parse(s));
}
return new MultiParameterList(exp.ToArray());
}
else if (aExpression.Contains('+'))
{
string[] parts = aExpression.Split('+');
List<IValue> exp = new List<IValue>(parts.Length);
for (int i = 0; i < parts.Length; i++)
{
string s = parts[i].Trim();
if (!string.IsNullOrEmpty(s))
exp.Add(Parse(s));
}
if (exp.Count == 1)
return exp[0];
return new OperationSum(exp.ToArray());
}
else if (aExpression.Contains('-'))
{
string[] parts = aExpression.Split('-');
List<IValue> exp = new List<IValue>(parts.Length);
if (!string.IsNullOrEmpty(parts[0].Trim()))
exp.Add(Parse(parts[0]));
for (int i = 1; i < parts.Length; i++)
{
string s = parts[i].Trim();
if (!string.IsNullOrEmpty(s))
exp.Add(new OperationNegate(Parse(s)));
}
if (exp.Count == 1)
return exp[0];
return new OperationSum(exp.ToArray());
}
else if (aExpression.Contains('*'))
{
string[] parts = aExpression.Split('*');
List<IValue> exp = new List<IValue>(parts.Length);
for (int i = 0; i < parts.Length; i++)
{
exp.Add(Parse(parts[i]));
}
if (exp.Count == 1)
return exp[0];
return new OperationProduct(exp.ToArray());
}
else if (aExpression.Contains('/'))
{
string[] parts = aExpression.Split('/');
List<IValue> exp = new List<IValue>(parts.Length);
if (!string.IsNullOrEmpty(parts[0].Trim()))
exp.Add(Parse(parts[0]));
for (int i = 1; i < parts.Length; i++)
{
string s = parts[i].Trim();
if (!string.IsNullOrEmpty(s))
exp.Add(new OperationReciprocal(Parse(s)));
}
return new OperationProduct(exp.ToArray());
}
else if (aExpression.Contains('^'))
{
int pos = aExpression.IndexOf('^');
var val = Parse(aExpression.Substring(0, pos));
var pow = Parse(aExpression.Substring(pos + 1));
return new OperationPower(val, pow);
}
foreach (var M in m_Funcs)
{
if (aExpression.StartsWith(M.Key))
{
var inner = aExpression.Substring(M.Key.Length);
var param = Parse(inner);
var multiParams = param as MultiParameterList;
IValue[] parameters;
if (multiParams != null)
parameters = multiParams.Parameters;
else
parameters = new IValue[] { param };
return new CustomFunction(M.Key, M.Value, parameters);
}
}
foreach (var C in m_Consts)
{
if (aExpression.StartsWith(C.Key))
{
return new CustomFunction(C.Key, (p) => C.Value(), null);
}
}
int index2a = aExpression.IndexOf('&');
int index2b = aExpression.IndexOf(';');
if (index2a >= 0 && index2b >= 2)
{
var inner = aExpression.Substring(index2a + 1, index2b - index2a - 1);
int bracketIndex;
if (int.TryParse(inner, out bracketIndex) && bracketIndex >= 0 && bracketIndex < m_BracketHeap.Count)
{
return Parse(m_BracketHeap[bracketIndex]);
}
else
throw new ParseException("Can't parse substitude token");
}
double doubleValue;
if (double.TryParse(aExpression, out doubleValue))
{
return new Number(doubleValue);
}
if (ValidIdentifier(aExpression))
{
if (m_Context.Parameters.ContainsKey(aExpression))
return m_Context.Parameters[aExpression];
var val = new Parameter(aExpression);
m_Context.Parameters.Add(aExpression, val);
return val;
}
throw new ParseException("Reached unexpected end within the parsing tree");
}
double[] InvokeMultiResult(double[] aParams, Parameter[] aParamList)
{
int count = System.Math.Min(aParamList.Length, aParams.Length);
for (int i = 0; i < count; i++)
{
if (aParamList[i] != null)
aParamList[i].Value = aParams[i];
}
return MultiValue;
}