Merge pull request #1 from zenangst/feature/semantic-compare

Feature/semantic compare

Source/Versions.swift

@@ -8,14 +8,47 @@
 
 import Foundation
 
-public extension NSString {
-
+public enum Semantic {
+    case Major, Minor, Patch, Same, Unknown
+}
+
+public extension String {
+
+    subscript (i: Int) -> Character {
+        return self[advance(self.startIndex, i)]
+    }
+
+    subscript (i: Int) -> String {
+        return String(self[i] as Character)
+    }
+
+    subscript (r: Range<Int>) -> String {
+        return substringWithRange(Range(start: advance(startIndex, r.startIndex), end: advance(startIndex, r.endIndex)))
+    }
+
     func newerThan(version :String) -> Bool {
         return self.compare(version, options: NSStringCompareOptions.NumericSearch) == NSComparisonResult.OrderedDescending
     }
 
     func olderThan(version: String) -> Bool {
-        return !self.isEqualToString(version) ? !self.newerThan(version) : false
+        let isEqual: Bool = self == version
+        return !isEqual ? !self.newerThan(version) : false
+    }
+
+    func semanticCompare(version: String) -> Semantic {
+        var semanticType = Semantic.Unknown
+
+        if self == version {
+            semanticType = Semantic.Same
+        } else if self[0] != version[advance(self.startIndex, 0)] {
+            semanticType = Semantic.Major
+        } else if self[0...2] != version[0...2] && self.olderThan(version) {
+            semanticType = Semantic.Minor
+        } else if self[0...4] != version[0...4] && self.olderThan(version) {
+            semanticType = Semantic.Patch
+        }
+
+        return semanticType
     }
 
 }

Versions Tests/Versions_Tests.swift

@@ -43,4 +43,11 @@ class Versions_Tests: XCTestCase {
         XCTAssertFalse("".newerThan("1.0"))
     }
 
+    func testSymanticVersioning() {
+        XCTAssertEqual(Semantic.Same, "1.0".semanticCompare("1.0"))
+        XCTAssertEqual(Semantic.Major, "1.0".semanticCompare("2.0"))
+        XCTAssertEqual(Semantic.Minor, "1.2".semanticCompare("1.3"))
+        XCTAssertEqual(Semantic.Patch, "1.2.1".semanticCompare("1.2.2"))
+    }
+
 }

Versions.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name = "Versions"
-  s.version = "0.1"
+  s.version = "0.2"
   s.summary = "Helping you find inner peace when comparing version numbers in Swift."
   s.description = <<-DESC
                    * Helping you find inner peace when comparing version numbers in Swift.