/// <returns>true if 'o' is an identifier</returns>
private bool IsFunctionApplication(Object o)
{
FunctionApplication FA = o as FunctionApplication;
return(FA != null);
}
private Object Parse(Object[] lexedStr, String str)
{
ArrayList L = new ArrayList(lexedStr.Length);
// parse all subexpressions; replace the Object[]s with FunctionApplications
for (int i = 0; i < lexedStr.Length; i++) {
Object[] lexedSubExprStr = lexedStr[i] as Object[];
if (lexedSubExprStr != null) // if subexpression, then parse that first:
L.Add(Parse(lexedSubExprStr, str));
else L.Add(lexedStr[i]);
}
for (int o = 0; o < m_operators.Length; o++)
{
// go from left-to-right or from right-to-left (depending on associativity) through the entire list of lexed objects
String currentOpSymbol = " " + m_operators[o].Symbol; // lexed operator have a ' ' in front of them
if (m_operators[o].Symbol == " ")
L = InsertSpaceOperators(L);
int startIdx = (m_operators[o].LeftAssociative ? 0 : L.Count-1);
int direction = (m_operators[o].LeftAssociative ? +1 : -1);
for (int l = startIdx; (l >= 0) && (l < L.Count); l += direction)
{
String opSymbol = L[l] as String;
// check if operator matches:
if ((opSymbol != null) && (opSymbol == currentOpSymbol))
{
// operator matches, check each possible case
if (m_operators[o].Unary)
{
if (m_operators[o].Postfix)
{
// postfix unary op
if (l < 1) continue; // we cannot match a postfix op if nothing sits before it
if (IsIdentifier(L[l - 1]) || IsFunctionApplication(L[l - 1]))
{
L[l - 1] = new FunctionApplication(m_operators[o].FunctionName, L[l - 1]);
L.RemoveAt(l);
l -= direction;
}
else continue;
}
else
{
// prefix unary op
if (l > L.Count-2) continue; // we cannot match a postfix op if nothing sits after it
if (IsIdentifier(L[l + 1]) || IsFunctionApplication(L[l + 1]))
{
L[l] = new FunctionApplication(m_operators[o].FunctionName, L[l + 1]);
L.RemoveAt(l+1);
l -= direction;
}
else continue;
}
}
else
{
// binary op
if ((l < 1) || (l > L.Count - 2)) continue; // we cannot match a binary op if nothing sits left or right
if ((IsIdentifier(L[l - 1]) || IsFunctionApplication(L[l - 1])) &&
(IsIdentifier(L[l + 1]) || IsFunctionApplication(L[l + 1])))
{
L[l-1] = new FunctionApplication(m_operators[o].FunctionName, L[l - 1], L[l + 1]);
L.RemoveRange(l, 2);
if (direction>0)
l -= direction;
}
else continue;
}
}
}
}
if (L.Count == 0) return null;
if (L.Count == 1)
return L[0];
else throw new Exception("Error parsing '" + str + "'");
}
private Object Parse(Object[] lexedStr, String str)
{
ArrayList L = new ArrayList(lexedStr.Length);
// parse all subexpressions; replace the Object[]s with FunctionApplications
for (int i = 0; i < lexedStr.Length; i++)
{
Object[] lexedSubExprStr = lexedStr[i] as Object[];
if (lexedSubExprStr != null) // if subexpression, then parse that first:
{
L.Add(Parse(lexedSubExprStr, str));
}
else
{
L.Add(lexedStr[i]);
}
}
for (int o = 0; o < m_operators.Length; o++)
{
// go from left-to-right or from right-to-left (depending on associativity) through the entire list of lexed objects
String currentOpSymbol = " " + m_operators[o].Symbol; // lexed operator have a ' ' in front of them
if (m_operators[o].Symbol == " ")
{
L = InsertSpaceOperators(L);
}
int startIdx = (m_operators[o].LeftAssociative ? 0 : L.Count - 1);
int direction = (m_operators[o].LeftAssociative ? +1 : -1);
for (int l = startIdx; (l >= 0) && (l < L.Count); l += direction)
{
String opSymbol = L[l] as String;
// check if operator matches:
if ((opSymbol != null) && (opSymbol == currentOpSymbol))
{
// operator matches, check each possible case
if (m_operators[o].Unary)
{
if (m_operators[o].Postfix)
{
// postfix unary op
if (l < 1)
{
continue; // we cannot match a postfix op if nothing sits before it
}
if (IsIdentifier(L[l - 1]) || IsFunctionApplication(L[l - 1]))
{
L[l - 1] = new FunctionApplication(m_operators[o].FunctionName, L[l - 1]);
L.RemoveAt(l);
l -= direction;
}
else
{
continue;
}
}
else
{
// prefix unary op
if (l > L.Count - 2)
{
continue; // we cannot match a postfix op if nothing sits after it
}
if (IsIdentifier(L[l + 1]) || IsFunctionApplication(L[l + 1]))
{
L[l] = new FunctionApplication(m_operators[o].FunctionName, L[l + 1]);
L.RemoveAt(l + 1);
l -= direction;
}
else
{
continue;
}
}
}
else
{
// binary op
if ((l < 1) || (l > L.Count - 2))
{
continue; // we cannot match a binary op if nothing sits left or right
}
if ((IsIdentifier(L[l - 1]) || IsFunctionApplication(L[l - 1])) &&
(IsIdentifier(L[l + 1]) || IsFunctionApplication(L[l + 1])))
{
L[l - 1] = new FunctionApplication(m_operators[o].FunctionName, L[l - 1], L[l + 1]);
L.RemoveRange(l, 2);
if (direction > 0)
{
l -= direction;
}
}
else
{
continue;
}
}
}
}
}
if (L.Count == 0)
{
return(null);
}
if (L.Count == 1)
{
return(L[0]);
}
else
{
throw new Exception("Error parsing '" + str + "'");
}
}
