Add subscripts to access components of entity

Sources/FirebladeECS/Entity+Component.swift

@@ -31,4 +31,23 @@ extension Entity {
         let compC: C? = get(component: C.self)
         return (compA, compB, compC)
     }
+
+    @inlinable
+    public subscript<C: Component, Value>(_ componentKeyPath: WritableKeyPath<C, Value>) -> Value? {
+        nonmutating set {
+            guard var comp = self.get(component: C.self),
+                let value = newValue else {
+                    return
+            }
+            comp[keyPath: componentKeyPath] = value
+        }
+        get {
+            self.get(component: C.self)?[keyPath: componentKeyPath]
+        }
+    }
+
+    @inlinable
+    public subscript<C: Component>(_ componentType: C.Type) -> C? {
+        self.get(component: componentType)
+    }
 }

Tests/FirebladeECSTests/EntityTests.swift

@@ -81,6 +81,33 @@ class EntityTests: XCTestCase {
 
         XCTAssertEqual(generator.count, 1)
     }
+
+    func testEntitySubscripts() {
+        let nexus = Nexus()
+        let pos = Position(x: 12, y: 45)
+        let name = Name(name: "SomeName")
+        let entity = nexus.createEntity(with: pos, name)
+
+        XCTAssertEqual(entity[\Position.x], 12)
+        XCTAssertEqual(entity[\Position.y], 45)
+        XCTAssertEqual(entity[\Name.name], "SomeName")
+
+        entity[\Position.x] = 67
+        entity[\Position.y] = 89
+        entity[\Name.name] = "AnotherName"
+
+        XCTAssertEqual(entity[\Position.x], 67)
+        XCTAssertEqual(entity[\Position.y], 89)
+        XCTAssertEqual(entity[\Name.name], "AnotherName")
+
+        entity[\Velocity.a] = 123
+        XCTAssertNil(entity[\Velocity.a])
+
+        entity[Position.self]?.x = 1234
+        XCTAssertEqual(entity[Position.self]?.x, 1234)
+        XCTAssertNil(entity[Velocity.self]?.a)
+    }
+
 }
 
 extension Sequence {

Tests/FirebladeECSTests/XCTestManifests.swift

@@ -29,6 +29,7 @@ extension EntityTests {
         ("testEntityEquality", testEntityEquality),
         ("testEntityIdentifierAndIndex", testEntityIdentifierAndIndex),
         ("testEntityIdGenerator", testEntityIdGenerator),
+        ("testEntitySubscripts", testEntitySubscripts),
         ("testRemoveAllComponentsFromEntity", testRemoveAllComponentsFromEntity)
     ]
 }