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;
}