| parser | Callback used to determine if a string can be converted into "TFilterConstant". Takes a string and returns a ParseResult object. This contains the success flag, and the actual converted value if it succeeded. |
IQueryEngineFilter The current filter.
Add a type parser specific to the filter.
Add a type parser specific to the filter that parses a string and returns a custom type. Used by custom operator handlers. This type parser will only be used by this filter and will not affect other filters.
// Add a new type parser for Vector2 written as "[x, y]", but only for this filter. // This type parser will not affect other filters. queryEngine.TryGetFilter("p", out var filter); filter.AddTypeParser(s => { // If the format requirement is not met, return a failure. if (!s.StartsWith("[") || !s.EndsWith("]")) return ParseResult<Vector2>.none; var trimmed = s.Trim('[', ']'); var vectorTokens = trimmed.Split(','); var vectorValues = vectorTokens.Select(token => float.Parse(token, CultureInfo.InvariantCulture.NumberFormat)).ToList(); if (vectorValues.Count != 2) return ParseResult<Vector2>.none; var vector = new Vector2(vectorValues[0], vectorValues[1]); // When the conversion succeeds, return a success. return new ParseResult<Vector2>(true, vector); });
See IQueryEngineFilter for a complete example.