Merge pull request #9 from RougeWare/feature/Swift-currentAverageOrNil

Added `currentAverageOrNil`
RougeWare · Apr 6, 2021 · 28b0692 · 28b0692
2 parents 376a908 + af8f5c1
commit 28b0692
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diff --git a/Tests/EfficientAveragerTests/testbench.swift b/Tests/EfficientAveragerTests/testbench.swift
@@ -5,26 +5,40 @@ final class Testbench: XCTestCase {
 
     func testExample() {
         var a = Averager<Double>(startingNumber: 13)
+        XCTAssertEqual(1, a.timesAveraged)
+        XCTAssertEqual(13, a.currentAverageOrNil)
         XCTAssertEqual(   13.0 , a.currentAverage)
         a.average(3)
         XCTAssertEqual(    8.0 , a.currentAverage)
         a.average(5, 12, 8, 7.3)
         XCTAssertEqual(   8.05 , a.currentAverage, accuracy: 0.001)
 
         var b = Averager<Double>()
+        XCTAssertEqual(b.currentAverage, 0)
+        XCTAssertEqual(b.timesAveraged, 0)
+        XCTAssertNil(b.currentAverageOrNil)
         XCTAssertEqual(    0.0 , b.currentAverage)
         b.average(13)
         XCTAssertEqual(   13.0 , b.currentAverage)
         b.average(55, 712.197, 18, 99)
         XCTAssertEqual(179.439 , b.currentAverage, accuracy: 0.001)
 
         var c = Averager<Double>()
+        XCTAssertEqual(c.currentAverage, 0)
+        XCTAssertEqual(c.timesAveraged, 0)
+        XCTAssertNil(c.currentAverageOrNil)
         c.average(-2147483648, 2147483647, 2147483647, -2147483648)
         XCTAssertEqual(   -0.5 , c.currentAverage)
 
         XCTAssertEqual(      6 , a.timesAveraged)
         XCTAssertEqual(      5 , b.timesAveraged)
         XCTAssertEqual(      4 , c.timesAveraged)
+
+
+        c.clear()
+        XCTAssertEqual(c.currentAverage, 0)
+        XCTAssertEqual(c.timesAveraged, 0)
+        XCTAssertNil(c.currentAverageOrNil)
     }
 
     static let allTests = [

diff --git a/lib/Averager.swift b/lib/Averager.swift
@@ -117,6 +117,7 @@ public extension Averager {
 
 
     /// Resets this averager to a state before any number has been averaged
+    @discardableResult
     mutating func clear() -> Averager<Number> {
         currentAverage = 0.0
         timesAveraged = 0
@@ -126,6 +127,18 @@ public extension Averager {
 
 
 
+public extension Averager {
+
+    /// If any numbers have been averaged, this returns the current average. Else, if no numbers have yet been averaged, this returns `nil`
+    var currentAverageOrNil: Number? {
+        timesAveraged > 0
+            ? currentAverage
+            : nil
+    }
+}
+
+
+
 /// Mutates the averager on the left-hand side so that the number on the right-hand side is averaged into it
 ///
 /// - Parameters: