Add call as function to all sets

Sources/FuzzyRelations/BinaryCartesianProduct.swift

@@ -34,6 +34,10 @@ extension BinaryCartesianProduct: FuzzySet {
     public subscript(_ u: U, _ v: V) -> Grade {
         grade(forElement: (u, v))
     }
+        
+    public func callAsFunction(_ u: U, _ v: V) -> Grade {
+        grade(forElement: (u, v))
+    }
 }
 
 extension BinaryCartesianProduct: AnyFuzzySetRepresentable {

Sources/FuzzyRelations/BinaryFuzzyRelation.swift

@@ -21,6 +21,10 @@ extension BinaryFuzzyRelation: FuzzySet {
     public subscript(_ u: U, _ v: V) -> Grade {
         grade(forElement: (u, v))
     }
+    
+    public func callAsFunction(_ u: U, _ v: V) -> Grade {
+        grade(forElement: (u, v))
+    }
 }
 
 extension BinaryFuzzyRelation: AnyFuzzySetRepresentable {

Sources/FuzzyRelations/FuzzyRelationsComposition.swift

@@ -63,4 +63,8 @@ extension FuzzyRelationsComposition: FuzzySet {
     public subscript(_ u: U, _ w: W) -> Grade {
         grade(forElement: (u, w))
     }
+    
+    public func callAsFunction(_ u: U, _ w: W) -> Grade {
+        grade(forElement: (u, w))
+    }
 }

Sources/FuzzyRelations/HomogenousFuzzyRelation.swift

@@ -21,6 +21,10 @@ extension HomogenousFuzzyRelation: FuzzySet {
     public subscript(_ u: U...) -> Grade {
         grade(forElement: u)
     }
+        
+    public func callAsFunction(_ u: U...) -> Grade {
+        grade(forElement: u)
+    }
 }
 
 extension HomogenousFuzzyRelation: AnyFuzzySetRepresentable {

Sources/FuzzyRelations/TernaryFuzzyRelation.swift

@@ -21,6 +21,10 @@ extension TernaryFuzzyRelation: FuzzySet {
     public subscript(_ u: U, _ v: V, _ w: W) -> Grade {
         grade(forElement: (u, v, w))
     }
+        
+    public func callAsFunction(_ u: U, _ v: V, _ w: W) -> Grade {
+        grade(forElement: (u, v, w))
+    }
 }
  
 extension TernaryFuzzyRelation: AnyFuzzySetRepresentable {

Sources/FuzzySets/FuzzySet.swift

@@ -15,4 +15,8 @@ public extension FuzzySet {
             grade(forElement: element)
         }
     }
+    
+    func callAsFunction(_ element: Universe) -> Grade {
+        grade(forElement: element)
+    }
 }

Tests/FuzzyLogicTests/Helpers/Helpers.swift

@@ -0,0 +1,7 @@
+import XCTest
+import FuzzySets
+
+func XCTAssertApproximatelyEqual(_ v1: Double, _ v2: Double, tolerance: Double = 0.0001) {
+    let diff = v1 - v2
+    XCTAssert(-tolerance <= diff && diff <= +tolerance)
+}

Tests/FuzzyLogicTests/ImplicationTests.swift

@@ -21,6 +21,7 @@ final class ImplicationTests: XCTestCase {
         
         let sut = bigPressure --> smallVolume
         
-        XCTAssertEqual(sut(4, 1, method: .standardStrict), 1.0)
+        XCTAssertApproximatelyEqual(sut(4, 1), 0.75)
+        XCTAssertApproximatelyEqual(sut(4, 1, method: .standardStrict), 1)
     }
 }

Tests/FuzzyRelationsTests/Helpers/Helpers.swift

@@ -5,13 +5,3 @@ public func XCTAssertApproximatelyEqual(_ v1: Double, _ v2: Double, tolerance: D
     let diff = v1 - v2
     XCTAssert(-tolerance <= diff && diff <= +tolerance)
 }
-
-public func assertExpectedGrade<E, S: FuzzySet>(element: E, expectedGrade: Grade, sut: S)
-where S.Universe == E {
-    let grade1 = sut[element]
-    let grade2 = sut.grade(forElement: element)
-    
-    XCTAssertApproximatelyEqual(grade1, grade2)
-    XCTAssertApproximatelyEqual(expectedGrade, grade1)
-    XCTAssertApproximatelyEqual(expectedGrade, grade2)
-}

Tests/FuzzySetsTests/Helpers/Helpers.swift

@@ -10,8 +10,12 @@ func assertExpectedGrade<E, S: FuzzySet>(element: E, expectedGrade: Grade, sut:
 where S.Universe == E {
     let grade1 = sut[element]
     let grade2 = sut.grade(forElement: element)
+    let grade3 = sut(element)
     
     XCTAssertApproximatelyEqual(grade1, grade2)
+    XCTAssertApproximatelyEqual(grade2, grade3)
+    XCTAssertApproximatelyEqual(grade1, grade3)
     XCTAssertApproximatelyEqual(expectedGrade, grade1)
     XCTAssertApproximatelyEqual(expectedGrade, grade2)
+    XCTAssertApproximatelyEqual(expectedGrade, grade3)
 }