/// <summary>
/// Extracts the individual expression elements, or tokens, from a string
/// representation of a mathematical expression before they are sent to
/// the calculation unit for final processing.
/// </summary>
/// <returns> A <see cref="System.Collections.Generic.List{DotNetAsm.ExpressionElement}"/>
/// </returns>
/// <param name="expression">The mathematical expression.</param>
public List <ExpressionElement> ParseElements(string expression)
{
var elements = new List <ExpressionElement>();
StringBuilder elementBuilder = new StringBuilder();
ExpressionElement currentElement = new ExpressionElement();
for (int i = 0; i < expression.Length; i++)
{
var c = expression[i];
if (char.IsWhiteSpace(c))
{
AddElement();
}
else if (c.IsOperator() || c == ',')
{
char next = i < expression.Length - 1 ? expression[i + 1] : char.MinValue;
bool nextIsOperand = char.IsLetterOrDigit(next) || next == '_' || next == '.' || next == '#';
if (currentElement.type != ExpressionElement.Type.Operator)
{
AddElement();
currentElement.type = ExpressionElement.Type.Operator;
if (c == ',')
{
currentElement.subType = ExpressionElement.Subtype.Binary;
}
else
{
if (currentElement.subType == ExpressionElement.Subtype.Open)
{
if (c.IsRadixOperator() && nextIsOperand)
{
currentElement.type = ExpressionElement.Type.Operand;
currentElement.subType = ExpressionElement.Subtype.None;
}
else
{
currentElement.subType = ExpressionElement.Subtype.Unary;
}
}
else
{
currentElement.subType = ExpressionElement.Subtype.Binary;
}
}
}
else if (!_compounds.Contains(elementBuilder.ToString() + c))
{
currentElement.subType = ExpressionElement.Subtype.Binary;
AddElement();
if (c.IsRadixOperator())
{
currentElement.type = ExpressionElement.Type.Operand;
currentElement.subType = ExpressionElement.Subtype.None;
}
else
{
currentElement.subType = ExpressionElement.Subtype.Unary;
}
}
elementBuilder.Append(c);
}
else if (c == '(' || c == ')')
{
AddElement();
if (c == '(' && elements.Count > 0 && (currentElement.type == ExpressionElement.Type.Operand && char.IsLetter(currentElement.word[0])))
{
// Convert operand expressions to functions where appropriate
elementBuilder.Append(elements.Last().word);
currentElement.type = ExpressionElement.Type.Function;
elements.RemoveAt(elements.Count - 1);
AddElement();
}
currentElement.type = ExpressionElement.Type.Group;
if (c == '(')
{
currentElement.subType = ExpressionElement.Subtype.Open;
}
else
{
currentElement.subType = ExpressionElement.Subtype.Close;
}
elementBuilder.Append(c);
}
else
{
if (currentElement.type != ExpressionElement.Type.Operand)
{
AddElement();
currentElement.type = ExpressionElement.Type.Operand;
currentElement.subType = ExpressionElement.Subtype.None;
}
elementBuilder.Append(c);
}
if (i == expression.Length - 1)
{
AddElement();
}
}
return(elements);
void AddElement()
{
if (elementBuilder.Length > 0)
{
currentElement.word = elementBuilder.ToString();
elementBuilder.Clear();
elements.Add(currentElement);
}
}
}
double Calculate(List <ExpressionElement> parsedElements)
{
var operators = new Stack <ExpressionElement>();
Stack <double> result = new Stack <double>();
int openParens = 0;
for (int i = 0; i < parsedElements.Count; i++)
{
var element = parsedElements[i];
if (openParens > 0)
{
int parmsPassed = 1;
int start = i + 1, len = 0;
for (i++; i < parsedElements.Count && openParens > 0; i++)
{
element = parsedElements[i];
if (element.word.Equals(",") && openParens < 2)
{
if (len == 0)
{
throw new Exception(); // we did a f(,n) thing
}
result.Push(Calculate(parsedElements.GetRange(start, len)));
parmsPassed++;
start = i + 1;
len = 0;
}
else
{
if (element.subType == ExpressionElement.Subtype.Open)
{
openParens++;
}
else if (element.subType == ExpressionElement.Subtype.Close)
{
openParens--;
}
if (openParens > 0)
{
len++;
}
}
}
if (len == 0)
{
throw new Exception(); // we did a f()/f(n,) thing
}
i--;
result.Push(Calculate(parsedElements.GetRange(start, len)));
result.Push(parmsPassed);
}
else if (element.type == ExpressionElement.Type.Operand)
{
if (element.word[0].IsRadixOperator())
{
var hexbin = element.word.Substring(1);
int radix;
if (element.word[0] == '%')
{
radix = 2;
hexbin = Regex.Replace(hexbin, @"^([#.]+)$", m => m.Groups[1].Value.Replace("#", "1").Replace(".", "0"));
}
else
{
radix = 16;
}
result.Push(Convert.ToInt64(hexbin, radix));
}
else
{
result.Push(double.Parse(element.word));
}
}
else if (element.type == ExpressionElement.Type.Function || element.subType == ExpressionElement.Subtype.Open)
{
operators.Push(element);
if (element.type == ExpressionElement.Type.Function)
{
openParens = 1;
}
else if (openParens > 0)
{
openParens++; // we're in a function track opening parens
}
}
else if (element.type == ExpressionElement.Type.Operator)
{
if (operators.Count > 0)
{
ExpressionElement topElement = new ExpressionElement();
var elemOrder = _operators[element].Item2;
topElement = operators.Peek();
while (topElement.type == ExpressionElement.Type.Function || topElement.type == ExpressionElement.Type.Operator || topElement.subType == ExpressionElement.Subtype.Open)
{
var topOrder = topElement.type == ExpressionElement.Type.Operator ? _operators[topElement].Item2 : int.MaxValue;
if (topElement.subType != ExpressionElement.Subtype.Open && topOrder >= elemOrder)
{
operators.Pop();
DoOperation(topElement);
if (operators.Count > 0)
{
topElement = operators.Peek();
}
else
{
break;
}
}
else
{
break;
}
}
}
operators.Push(element);
}
else if (element.subType == ExpressionElement.Subtype.Close)
{
if (operators.Count > 0)
{
var topElement = operators.Peek();
while (topElement.subType != ExpressionElement.Subtype.Open)
{
operators.Pop();
DoOperation(topElement);
if (operators.Count == 0)
{
throw new Exception();
}
topElement = operators.Peek();
}
if (topElement.subType == ExpressionElement.Subtype.Open)
{
operators.Pop();
}
}
}
}
if (openParens > 0)
{
throw new Exception();
}
while (operators.Count > 0)
{
DoOperation(operators.Pop());
}
void DoOperation(ExpressionElement op)
{
OperationDef operation = null;
List <double> parms = new List <double> {
result.Pop()
};
if (op.type == ExpressionElement.Type.Function)
{
operation = _functions[op.word];
var parmcount = operation.Item2;
if (parmcount != (int)parms.Last())
{
throw new Exception(); // parms passed does not match function's definition
}
parms.Clear();
while (parmcount-- > 0)
{
parms.Add(result.Pop());
}
}
else
{
operation = _operators[op];
if (op.subType == ExpressionElement.Subtype.Binary)
{
parms.Add(result.Pop());
}
if (op.arithmeticType == ExpressionElement.ArithmeticType.Boolean &&
parms.Any(p => !(p.AlmostEquals(1) || p.AlmostEquals(0))))
{
throw new Exception();
}
if (op.arithmeticType == ExpressionElement.ArithmeticType.Integral &&
parms.Any(p => !p.AlmostEquals(Math.Round(p))))
{
throw new Exception();
}
}
result.Push(operation.Item1(parms));
}
if (result.Count > 1)
{
throw new Exception();
}
return(result.Pop());
}
/// <summary>
/// Translates all special symbols in the expression into a
/// <see cref="System.Collections.Generic.List{DotNetAsm.ExpressionElement}"/>
/// for use by the evualator.
/// </summary>
/// <returns>The expression symbols.</returns>
/// <param name="line">The current source line.</param>
/// <param name="expression">The expression to evaluate.</param>
/// <param name="scope">The current scope.</param>
/// <param name="errorOnNotFound">If set to <c>true</c> raise an error
/// if a symbol encountered in the expression was not found.</param>
public List <ExpressionElement> TranslateExpressionSymbols(SourceLine line, string expression, string scope, bool errorOnNotFound)
{
char lastTokenChar = char.MinValue;
StringBuilder translated = new StringBuilder(), symbolBuilder = new StringBuilder();
for (int i = 0; i < expression.Length; i++)
{
char c = expression[i];
if (c == '\'' || c == '"')
{
var literal = expression.GetNextQuotedString(i);
var unescaped = literal.TrimOnce(c);
if (unescaped.Contains("\\"))
{
unescaped = Regex.Unescape(unescaped);
}
var bytes = Assembler.Encoding.GetBytes(unescaped);
if (bytes.Length > sizeof(int))
{
throw new OverflowException(literal);
}
if (bytes.Length < sizeof(int))
{
Array.Resize(ref bytes, sizeof(int));
}
var encodedValue = BitConverter.ToInt32(bytes, 0);
translated.Append(encodedValue);
i += literal.Length - 1;
lastTokenChar = '0'; // can be any operand
}
else if ((c == '*' || c == '-' || c == '+') &&
(lastTokenChar.IsOperator() || lastTokenChar == '(' || lastTokenChar == char.MinValue))
{
bool isSpecial = false;
if (c == '*' && (lastTokenChar == '(' || i == 0 || expression[i - 1] != '*'))
{
isSpecial = true;
translated.Append(Assembler.Output.LogicalPC.ToString());
}
else if (lastTokenChar == '(' ||
lastTokenChar == char.MinValue || (lastTokenChar.IsOperator()) && char.IsWhiteSpace(expression[i - 1]))
{
int j = i, k;
for (; j < expression.Length && expression[j] == c; j++)
{
symbolBuilder.Append(c);
}
for (k = j; k < expression.Length && char.IsWhiteSpace(expression[k]); k++)
{
}
if (j >= expression.Length ||
(lastTokenChar == '(' && expression[k] == ')') ||
((lastTokenChar == char.MinValue || lastTokenChar.IsOperator()) &&
char.IsWhiteSpace(expression[k - 1]) && expression[k].IsOperator()))
{
isSpecial = true;
translated.Append(ConvertAnonymous(symbolBuilder.ToString(), line, errorOnNotFound));
i = j - 1;
}
symbolBuilder.Clear();
}
if (isSpecial)
{
lastTokenChar = translated[translated.Length - 1];
}
else
{
lastTokenChar = c;
translated.Append(c);
}
}
else
{
if (!char.IsWhiteSpace(c))
{
lastTokenChar = c;
}
translated.Append(c);
}
}
var elements = Assembler.Evaluator.ParseElements(translated.ToString()).ToList();
for (int i = 0; i < elements.Count; i++)
{
if (elements[i].type == ExpressionElement.Type.Operand && (elements[i].word[0] == '_' || char.IsLetter(elements[i].word[0])))
{
var symbol = elements[i].word;
if (_constants.ContainsKey(symbol))
{
symbol = _constants[symbol].ToString();
}
else
{
symbol = GetNamedSymbolValue(symbol, line, scope);
}
if (symbol[0] == '-')
{
elements.Insert(i, new ExpressionElement
{
word = "-",
type = ExpressionElement.Type.Operator,
subType = ExpressionElement.Subtype.Unary
});
i++;
symbol = symbol.Substring(1);
}
elements[i] = new ExpressionElement
{
word = symbol,
type = ExpressionElement.Type.Operand,
subType = ExpressionElement.Subtype.None
};
}
}
return(elements);
}
