private static void ToString(Expression x, StringBuilder sb)
{
if (x is OpNode)
{
OpNode o = (OpNode)x;
sb.Append("(");
ToString(o.leftChild, sb);
sb.Append(o.GetSymbol());
ToString(o.rightChild, sb);
sb.Append(")");
}
else
{
if (x is TermNode)
{
TermNode t = (TermNode)x;
if (t.GetNegate())
{
sb.Append("(");
sb.Append("-");
}
sb.Append(t.GetName());
if (t is FuncNode)
{
FuncNode f = (FuncNode)t;
sb.Append("(");
if (f.NumChildren() > 0)
{
ToString(f.Child(0), sb);
}
for (int i = 1; i < f.NumChildren(); i++)
{
sb.Append(", ");
ToString(f.Child(i), sb);
}
sb.Append(")");
}
if (t.GetNegate())
{
sb.Append(")");
}
}
else
{
if (x is ValNode)
{
sb.Append(((ValNode)x).val);
}
}
}
}
private static void GetTermNames(Expression x, Bag b, bool varNames)
{
if (x is OpNode)
{
OpNode o = (OpNode)x;
GetTermNames(o.leftChild, b, varNames);
GetTermNames(o.rightChild, b, varNames);
}
else
{
if (x is VarNode)
{
if (varNames)
{
VarNode v = (VarNode)x;
if (!b.Contains(v.name))
{
b.Add(v.name);
}
}
}
else
{
if (x is FuncNode)
{
FuncNode f = (FuncNode)x;
if (!varNames)
{
if (!b.Contains(f.name))
{
b.Add(f.name);
}
}
for (int i = 0; i < f.NumChildren(); i++)
{
GetTermNames(f.Child(i), b, varNames);
}
}
}
}
}
private static Expression Build(string s, int indexErrorOffset)
{
// do not remove (required condition for functions with no parameters, e.g. Pi())
if (s.Trim().Length == 0)
{
return(null);
}
Stack s1 = Stack.Allocate();
// contains expression nodes
Stack s2 = Stack.Allocate();
try
{
// contains open brackets ( and operators ^,*,/,+,-
bool term = true;
// indicates a term should come next, not an operator
bool signed = false;
// indicates if the current term has been signed
bool negate = false;
// indicates if the sign of the current term is negated
for (int i = 0; i < s.Length; i++)
{
char c = s[i];
if (c == ' ' || c == '\t' || c == '\n')
{
continue;
}
if (term)
{
if (c == '(')
{
if (negate)
{
throw new ExpressionParseException("Open bracket found after negate.", i);
}
s2.Push("(");
}
else
{
if (!signed && (c == '+' || c == '-'))
{
signed = true;
if (c == '-')
{
negate = true;
}
}
else
{
// by default negate is false
if (c >= '0' && c <= '9' || c == '.')
{
int j = i + 1;
while (j < s.Length)
{
c = s[j];
if (c >= '0' && c <= '9' || c == '.')
{
j++;
}
else
{
// code to account for "computerized scientific notation"
if (c == 'e' || c == 'E')
{
j++;
if (j < s.Length)
{
c = s[j];
if (c != '+' && c != '-' && (c < '0' || c > '9'))
{
throw new ExpressionParseException(
"Expected digit, plus sign or minus sign but found: " +
c.ToString(), j + indexErrorOffset);
}
j++;
}
while (j < s.Length)
{
c = s[j];
if (c < '0' || c > '9')
{
break;
}
j++;
}
break;
}
else
{
break;
}
}
}
double d = 0;
string _d = Sharpen.Runtime.Substring(s, i, j);
try
{
d = double.Parse(_d);
}
catch
{
throw new ExpressionParseException("Improperly formatted value: " + _d,
i + indexErrorOffset);
}
if (negate)
{
d = -d;
}
s1.Push(new ValNode(d));
i = j - 1;
negate = false;
term = false;
signed = false;
}
else
{
if (c != ',' && c != ')' && c != '^' && c != '*' && c != '/' && c != '+' &&
c != '-')
{
int j = i + 1;
while (j < s.Length)
{
c = s[j];
if (c != ',' && c != ' ' && c != '\t' && c != '\n' && c != '(' &&
c != ')' && c != '^' && c != '*' && c != '/' && c != '+' && c != '-')
{
j++;
}
else
{
break;
}
}
if (j < s.Length)
{
int k = j;
while (c == ' ' || c == '\t' || c == '\n')
{
k++;
if (k == s.Length)
{
break;
}
c = s[k];
}
if (c == '(')
{
FuncNode fn = new FuncNode(Sharpen.Runtime.Substring(s, i, j), negate);
int b = 1;
int kOld = k + 1;
while (b != 0)
{
k++;
if (k >= s.Length)
{
throw new ExpressionParseException(
"Missing function close bracket.", i + indexErrorOffset);
}
c = s[k];
if (c == ')')
{
b--;
}
else
{
if (c == '(')
{
b++;
}
else
{
if (c == ',' && b == 1)
{
Expression o = Build(
Sharpen.Runtime.Substring(s, kOld, k), kOld);
if (o == null)
{
throw new ExpressionParseException(
"Incomplete function.",
kOld + indexErrorOffset);
}
fn.Add(o);
kOld = k + 1;
}
}
}
}
Expression o_1 = Build(Sharpen.Runtime.Substring(s, kOld, k), kOld);
if (o_1 == null)
{
if (fn.NumChildren() > 0)
{
throw new ExpressionParseException("Incomplete function.",
kOld + indexErrorOffset);
}
}
else
{
fn.Add(o_1);
}
s1.Push(fn);
i = k;
}
else
{
s1.Push(new VarNode(Sharpen.Runtime.Substring(s, i, j), negate));
i = k - 1;
}
}
else
{
s1.Push(new VarNode(Sharpen.Runtime.Substring(s, i, j), negate));
i = j - 1;
}
negate = false;
term = false;
signed = false;
}
else
{
throw new ExpressionParseException("Unexpected character: " + c.ToString(),
i + indexErrorOffset);
}
}
}
}
}
else
{
if (c == ')')
{
Stack s3 = Stack.Allocate();
Stack s4 = Stack.Allocate();
try
{
while (true)
{
if (s2.IsEmpty())
{
throw new ExpressionParseException("Missing open bracket.",
i + indexErrorOffset);
}
object o = s2.Pop();
if (o.Equals("("))
{
break;
}
s3.AddToTail(s1.Pop());
s4.AddToTail(o);
}
s3.AddToTail(s1.Pop());
s1.Push(Build(s3, s4));
}
finally
{
s3.ReleaseReference();
s4.ReleaseReference();
}
}
else
{
if (c == '^' || c == '*' || c == '/' || c == '+' || c == '-')
{
term = true;
s2.Push(c.ToString());
}
else
{
throw new ExpressionParseException(
"Expected operator or close bracket but found: " + c.ToString(),
i + indexErrorOffset);
}
}
}
}
if (s1.Size() != s2.Size() + 1)
{
throw new ExpressionParseException("Incomplete expression.", indexErrorOffset + s.Length);
}
return(Build(s1, s2));
}
finally
{
s1.ReleaseReference();
s2.ReleaseReference();
}
}
