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Close| 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 converted value if it succeeds. |
Adds a type parser that parses a string and returns a custom type. Used by custom operator handlers (see AddOperatorHandler).
<TFilterConstant>: The type of the parsed operand that is on the right-hand side of the operator.
using System.Collections.Generic; using System.Globalization; using System.Linq; using UnityEditor; using UnityEditor.Search; using UnityEngine; static class Example_QueryEngine_AddTypeParser { static List<MyObjectType> s_Data; [MenuItem("Examples/QueryEngine/AddTypeParser")] public static void RunExample() { // Set up the query engine var queryEngine = new QueryEngine<MyObjectType>(); queryEngine.AddFilter("id", myObj => myObj.id); queryEngine.AddFilter("p", myObj => myObj.position, new[] { "=", "!=" }); queryEngine.SetSearchDataCallback(myObj => new[] { myObj.id.ToString(), myObj.name }); // Add a new type parser for Vector2 written as "[x, y]" queryEngine.AddTypeParser<Vector2>(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); }); queryEngine.AddOperatorHandler("=", (Vector2 ev, Vector2 fv) => ev == fv); queryEngine.AddOperatorHandler("!=", (Vector2 ev, Vector2 fv) => ev != fv); s_Data = new List<MyObjectType>() { new MyObjectType { id = 0, name = "Test 1", position = new Vector2(0, 0), active = false }, new MyObjectType { id = 1, name = "Test 2", position = new Vector2(0, 1), active = true }, new MyObjectType { id = 2, name = "Test 3", position = new Vector2(1, 0), active = false }, new MyObjectType { id = 3, name = "Test 4", position = new Vector2(1.2f, 0), active = false }, }; // Find all items that are located at position [0, 1] var query = queryEngine.ParseQuery("p=\"[0, 1]\""); var filteredData = query.Apply(s_Data).ToList(); Debug.Assert(filteredData.Count == 1, $"There should be 1 item in the filtered list but found {filteredData.Count} items."); Debug.Assert(filteredData.Contains(s_Data[1]), "Test 2 should be in the list as its position [0, 1]."); } class MyObjectType { public int id { get; set; } public string name { get; set; } = string.Empty; public Vector2 position { get; set; } = Vector2.zero; public bool active { get; set; } public override string ToString() { return $"({id}, {name}, ({position.x}, {position.y}), {active})"; } } }