/// <summary>
/// Evaluates an expression and returns a <see cref="Variable" />.
/// </summary>
/// <param name="expression">The expression to evaluate.</param>
/// <param name="data">The <see cref="Data" /> object containing all of the story variables.</param>
/// <returns>A <see cref="Variable" /> instance containing the results of the evaluation.</returns>
private static Variable Evaluate(string expression, Data data)
{
var lexer = new MathLexer(new AntlrInputStream(expression));
var parser = new MathParser(new CommonTokenStream(lexer));
var visitor = new MathVisitor {
Data = data
};
return(visitor.Visit(parser.expr()));
}
/// <summary>
/// 执行函数
/// </summary>
/// <returns></returns>
public Operand Evaluate()
{
if (_context == null)
{
LastError = "Please use Parse to compile formula !";
throw new Exception("Please use Parse to compile formula !");
}
var visitor = new MathVisitor();
visitor.GetParameter += GetParameter;
visitor.excelIndex = UseExcelIndex ? 1 : 0;
visitor.DiyFunction += ExecuteDiyFunction;
return(visitor.Visit(_context));
}