Function: AcceptIf (#198)

AcceptIf returns another function of the same signature as the apply function but also includes a bool value to indicate success or failure.
A predicate function that takes an argument of type T and returns a bool.
An apply function that also takes an argument of type T and returns a modified value of the same type.

function/function_example_test.go

@@ -145,3 +145,32 @@ func ExamplePipeline() {
 	// Output:
 	// 36
 }
+
+func ExampleAcceptIf() {
+
+	adder := AcceptIf(
+		And(
+			func(x int) bool {
+				return x > 10
+			}, func(x int) bool {
+				return x%2 == 0
+			}),
+		func(x int) int {
+			return x + 1
+		},
+	)
+
+	result, ok := adder(20)
+	fmt.Println(result)
+	fmt.Println(ok)
+
+	result, ok = adder(21)
+	fmt.Println(result)
+	fmt.Println(ok)
+
+	// Output:
+	// 21
+	// true
+	// 0
+	// false
+}