/// Read expression from string, evaluate it and return the value
public object Eval(string expression)
{
if (expression == null)
return null;
IOperation ex = _exprCache[expression];
if (ex == null)
{
using (var sr = new ParsingReader(new StringReader(expression)))
{
ex = new Parser(TokenSpecialCharacters).Parse(sr);
sr.SkipWhiteSpace();
sr.ReadAndThrowIfNot(-1);
_exprCache[expression] = ex;
}
}
if (ex == null)
return null;
return Eval(ex);
}
/// Read multi-expression (like ${a|b|=3+5}) from the string, evaluate it and return the value
public object EvalMulti(string multiExpression)
{
if (multiExpression==null)
return null;
IOperation o = _exprCache[multiExpression];
if (o == null)
{
using (var sr = new ParsingReader(new StringReader(multiExpression)))
{
o = new Parser(TokenSpecialCharacters).ParseMulti(sr);
sr.SkipWhiteSpace();
sr.ReadAndThrowIfNot(-1);
_exprCache[multiExpression] = o;
}
}
return Eval(o);
}
public TokenQueue(Parser p, ParsingReader r)
{
_reader = r;
_parser = p;
}
