public static BaseExpression Parse(ParsingEnvironment env, string input)
{
var vistor = new MyExpressionParser()
{
_environment = env
};
ICharStream stream = CharStreams.fromString(input);
ExpressionLexer lexer = new ExpressionLexer(stream);
lexer.AddErrorListener(vistor);
ITokenStream tokens = new CommonTokenStream(lexer);
var parser = new ExpressionParser(tokens);
parser.AddErrorListener(vistor);
parser.BuildParseTree = true;
var tree = parser.completeExpression();
// TODO: the default error listens write to the console
BaseExpression result = vistor.Visit(tree);
if (result is null)
{
// Probably missed an override of ExpressionBaseVisitor if this is thrown
throw new Exception("Programming error, no expression returned.");
}
return(result);
}
public static BaseExpression Parse(ParsingEnvironment env, XElement node)
{
switch (node.Name.LocalName)
{
case "ValueFromFirstFormThatExists":
return(new ValueFromFirstFormThatExistsExpression(env, node));
case "SelectBasedOnStatus":
return(new SelectBasedOnStatusExpression(env, node));
case "Form8949Lines":
return(new Form8949LinesLiteralExpression(node));
default:
throw new FileLoadException(node, "Unknown node type: " + node.Name);
}
}
public static BaseExpression Parse(ParsingEnvironment env, XElement node, string attributeName)
{
var calcStr = node.Attribute(attributeName)?.Value;
var calcNode = node.Elements().ToArray();
//make sure there is at most one Calc definition
if (calcStr is null && calcNode.Length == 0)
{
return(null);
}
if (calcStr is object && calcNode.Length > 0)
{
throw new FileLoadException(node, $"Line contains both and {attributeName} attribute and a {attributeName} node.");
}
// do some light validation
if (calcStr is not null)
{
if (string.IsNullOrWhiteSpace(calcStr))
{
if (calcStr is null)
{
return(null);
}
throw new FileLoadException(node, "Empty expression.");
}
}
else if (calcNode.Length > 1)
{
throw new FileLoadException(calcNode[1], $"Multiple {attributeName} sub-elements.");
}
try
{
return(calcStr is not null?Parse(env, calcStr) : XmlExpressionParser.Parse(env, calcNode[0]));
}
catch (Exception ex)
{
throw new FileLoadException(node, $"Failed to parse {attributeName}.", ex);
}
}