public object Evaluate()
{
if (expression == null)
{
throw new ExpressionEvaluatorException("the expression should not be empty or null");
}
object result;
try
{
ExpressionLexer lexer = new ExpressionLexer(expression);
ExpressionParser parser = new ExpressionParser(
new TokenStream(lexer),
context);
ExpressionNode tree = parser.Parse();
ExpressionVisitor visitor = new ExpressionVisitor(context);
IExpression expr = ExpressionBuilder.Build(tree);
expr.Accept(visitor);
result = visitor.EvaluationResult;
}
catch (Exception e) // reports all unexpected exceptions
{
context.ReportError(
String.Format(
CultureInfo.InvariantCulture,
"failed to evaluate expression '{0}' : '{1}'",
expression,
e.Message));
result = expression;
}
return(result);
}
public TokenStream(ExpressionLexer lexer)
{
this.lexer = lexer;
}
public TokenStream(ExpressionLexer lexer)
{
this.lexer = lexer;
}
public object Evaluate()
{
if (expression == null)
{
throw new ExpressionEvaluatorException("the expression should not be empty or null");
}
object result;
try
{
ExpressionLexer lexer = new ExpressionLexer(expression);
ExpressionParser parser = new ExpressionParser(
new TokenStream(lexer),
context);
ExpressionNode tree = parser.Parse();
ExpressionVisitor visitor = new ExpressionVisitor(context);
IExpression expr = ExpressionBuilder.Build(tree);
expr.Accept(visitor);
result = visitor.EvaluationResult;
}
catch (Exception e) // reports all unexpected exceptions
{
context.ReportError(
String.Format(
CultureInfo.InvariantCulture,
"failed to evaluate expression '{0}' : '{1}'",
expression,
e.Message));
result = expression;
}
return result;
}