Merge pull request #29 from nakiostudio/issue-28-extend-multiplier-usage

ISSUE-28 Extend multipliers usage

.fastlane/Fastfile

@@ -12,7 +12,7 @@ platform :ios do
     scan(
       scheme: scheme,
       workspace: workspace,
-      devices: ["iPhone 6s"],
+      device: "iPhone 6s",
       code_coverage: true
     )
 

.travis.yml

@@ -6,6 +6,7 @@ branches:
     - develop
 before_install:
   - bundle install
+  - instruments -s
 script:
   - set -o pipefail
   - fastlane travis

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## v.1.1.0
+
+* Now it's possible to combine `multipliers` with `Equal`, `GreaterThatOrEqual`
+and `LessThanOrEqual` relations.
+
+```swift
+// i.e.
+Width(>=20*0.5) // value = 20, multiplier = 0.5, relation = .GreaterThanOrEqual
+Width(<=20*0.5) // value = 20, multiplier = 0.5, relation = .LessThanOrEqual
+Width(==20*0.5) // value = 20, multiplier = 0.5, relation = .Equal
+```
+
 # v.1.0.0
 
 * Improved performance, benchmarks show up to a 250% improvement applying `Attributes` with the apply operator `<-`, resolving

EasyPeasy.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = "EasyPeasy"
-  s.version          = "1.0.0"
+  s.version          = "1.1.0"
   s.summary          = "EasyPeasy is a Swift framework that eases the creation of
                         Autolayout constraints programmatically"
   s.description      = <<-DESC

EasyPeasy/Attribute.swift

@@ -64,7 +64,25 @@ public class Attribute {
     /// Element identifying the node this attribute will be 
     /// stored in
     internal lazy var signature: String = {
-        return String.easy_signature(for: self)
+        // Signature of the create `ReferenceAttribute` of
+        // the passed `Attribute`
+        var signature = self.createAttribute.signatureString
+
+        // Signature of the `Relation` of the passed `Attribute`
+        switch self.constant.relation {
+        case .Equal:
+            signature += "eq_"
+        case .GreaterThanOrEqual:
+            signature += "gt_"
+        case .LessThanOrEqual:
+            signature += "lt_"
+        }
+
+        // Signature of the `Priority` of the passed
+        // `Attribute`
+        signature += String(self.priority.layoutPriority())
+
+        return signature
     }()
 
     /**
@@ -74,7 +92,7 @@ public class Attribute {
         - returns: the `Attribute` instance created
      */
     public init() {
-        self.constant = Constant(0.0)
+        self.constant = Constant(value: 0.0, relation: .Equal, multiplier: 1.0)
         self.priority = .HighPriority
     }
 
@@ -86,7 +104,7 @@ public class Attribute {
         - returns: the `Attribute` instance created
      */
     public init(_ value: CGFloat) {
-        self.constant = Constant(value)
+        self.constant = Constant(value: value, relation: .Equal, multiplier: 1.0)
         self.priority = .HighPriority
     }
 
@@ -152,11 +170,11 @@ public class Attribute {
         let layoutConstraint = NSLayoutConstraint(
             item: item,
             attribute: self.createAttribute.layoutAttribute,
-            relatedBy: self.constant.layoutRelation(),
+            relatedBy: self.constant.relation,
             toItem: self.referenceItem,
             attribute: self.referenceAttributeHelper().layoutAttribute,
-            multiplier: self.constant.layoutMultiplier(),
-            constant: (self.constant.layoutValue() * constantFactor)
+            multiplier: self.constant.multiplier,
+            constant: (self.constant.value * constantFactor)
         )
 
         // Set priority
@@ -204,8 +222,8 @@ public class Attribute {
 }
 
 /**
-    Methods applicable to an `Array` of `Attributes`. The modifiers
-    will affect to each one of the `Attributes` within the `Array`
+    Methods applicable to an `Array` of `Attributes`. The `Constants`
+    will apply to each one of the `Attributes` within the `Array`
     overriding the values individually set.
  */
 public extension Array where Element: Attribute {

EasyPeasy/Constant.swift

@@ -15,20 +15,9 @@ import AppKit
 #endif
 
 /**
-    Modifier used when a relationship is created between the target `UIView`
-    and the reference `UIView`. 
- 
-    Unlike `NSLayoutRelation` this enum also includes a `MultipliedBy` case
-    which acts as the `multiplier property of a `NSLayoutConstraint`
+    Alias of `NSLayoutRelation`
  */
-public enum Modifier {
-
-    case EqualTo
-    case GreaterThanOrEqualTo
-    case LessThanOrEqualTo
-    case MultipliedBy
-
-}
+typealias Relation = NSLayoutRelation
 
 /**
     Struct that aggregates `NSLayoutRelation`, constant and multiplier of a 
@@ -39,94 +28,62 @@ public struct Constant {
     /// Value of the constant
     let value: CGFloat
 
-    /// Modifier applied to the `value` of the `Constant`
-    var modifier: Modifier
+    /// Relation that applies to the `value` of the `Constant`
+    let relation: Relation
 
-    /**
-        This initializer creates a `Constant` with the value supplied
-        and the modifier `.EqualTo`
-        - parameter value: Value of the `Constant`
-        - returns: the `Constant` struct created
-     */
-    init(_ value: CGFloat) {
-        self.value = value
-        self.modifier = .EqualTo
-    }
+    /// Multiplier of the `Constant`
+    let multiplier: CGFloat
 
     /**
-        This initializer creates a `Constant` with the `value` and `modifier` 
-        supplied.
+        This initializer creates a `Constant` with the `value`, `relations`
+        and `multiplier` supplied.
         - parameter value: Value of the `Constant`
-        - parameter modifier: Modifier applied to the `value`
+        - parameter relation: `Relation that applies to the `value`
+        - parameter multiplier: Multiplier of the `Constant`
         - returns: the `Constant` struct created
      */
-    init(value: CGFloat, modifier: Modifier) {
+    init(value: CGFloat, relation: Relation, multiplier: CGFloat) {
         self.value = value
-        self.modifier = modifier
-    }
-
-    /**
-        `NSLayoutRelation` equivalent to the `modifier` of the `Constant`
-        - returns: `NSLayoutRelation` equivalent
-     */
-    internal func layoutRelation() -> NSLayoutRelation {
-        switch self.modifier {
-        case .EqualTo: return .Equal
-        case .LessThanOrEqualTo: return .LessThanOrEqual
-        case .GreaterThanOrEqualTo: return .GreaterThanOrEqual
-        case .MultipliedBy: return .Equal
-        }
-    }
-
-    /**
-        Determines the `CGFloat` value of the multiplier for the `modifier`
-        property
-        - returns: `CGFloat` multiplier
-     */
-    internal func layoutMultiplier() -> CGFloat {
-        switch self.modifier {
-        case .EqualTo: return 1.0
-        case .LessThanOrEqualTo: return 1.0
-        case .GreaterThanOrEqualTo: return 1.0
-        case .MultipliedBy: return CGFloat(self.value)
-        }
-    }
-
-    /**
-        Value of the `Constant`
-        - returns: `CGFloat` value of the `Constant`
-     */
-    internal func layoutValue() -> CGFloat {
-        switch self.modifier {
-        case .MultipliedBy: return 0.0
-        default: return CGFloat(self.value)
-        }
+        self.relation = relation
+        self.multiplier = multiplier
     }
 
 }
 
+prefix operator == {}
+
+/**
+    Prefix operator that eases the creation of a `Constant` with a
+    `.Equal` relation
+    - parameter rhs: Value for the `Constant`
+    - returns: The resulting `Constant` struct
+ */
+public prefix func == (rhs: CGFloat) -> Constant {
+    return Constant(value: rhs, relation: .Equal, multiplier: 1.0)
+}
+
 prefix operator >= {}
 
 /**
     Prefix operator that eases the creation of a `Constant` with a
-    `.GreaterThanOrEqualTo` modifier.
+    `.GreaterThanOrEqual` relation
     - parameter rhs: Value for the `Constant`
     - returns: The resulting `Constant` struct
  */
 public prefix func >= (rhs: CGFloat) -> Constant {
-    return Constant(value: rhs, modifier: .GreaterThanOrEqualTo)
+    return Constant(value: rhs, relation: .GreaterThanOrEqual, multiplier: 1.0)
 }
 
 prefix operator <= {}
 
 /**
     Prefix operator that eases the creation of a `Constant` with a
-    `.LessThanOrEqualTo` modifier.
+    `.LessThanOrEqual` relation
     - parameter rhs: Value for the `Constant`
     - returns: The resulting `Constant` struct
  */
 public prefix func <= (rhs: CGFloat) -> Constant {
-    return Constant(value: rhs, modifier: .LessThanOrEqualTo)
+    return Constant(value: rhs, relation: .LessThanOrEqual, multiplier: 1.0)
 }
 
 prefix operator * {}
@@ -138,5 +95,21 @@ prefix operator * {}
     - returns: The resulting `Constant` struct
  */
 public prefix func * (rhs: CGFloat) -> Constant {
-    return Constant(value: rhs, modifier: .MultipliedBy)
+    return Constant(value: rhs, relation: .Equal, multiplier: rhs)
+}
+
+/**
+    Infix operator that applies the `multiplier` at the right hand side to the
+    `Constant` at the left hand side. 
+    i.e. `Width((>=200.0)*0.5)` creates a `Constant` with `multiplier = 0.5`,
+    `relation = .GreaterThanOrEqual` and `value = 200.0`.
+    If the left hand side `Constant` already has a `multiplier` defined the 
+    resulting `multiplier` will be the multiplication of both, previous and new
+    `multipliers`.
+    - parameter lhs: a `Constant`
+    - parameter rhs: a `CGFloat` multiplier
+    - returns: A new `Constant` with the `multiplier` applied
+ */
+public func * (lhs: Constant, rhs: CGFloat) -> Constant {
+    return Constant(value: lhs.value, relation: lhs.relation, multiplier: lhs.multiplier * rhs)
 }

EasyPeasy/ReferenceAttribute.swift

@@ -163,3 +163,47 @@ public enum ReferenceAttribute {
     }
 
 }
+
+#if os(iOS) || os(tvOS)
+
+/**
+    Extends `ReferenceAttribute` to ease the creation of
+    an `Attribute` signature
+ */
+internal extension ReferenceAttribute {
+
+    /// Signature of a `ReferenceAttribute`. Two possible values
+    /// depending on the Axis the `ReferenceAttribute` applies
+    var signatureString: String {
+        switch self {
+        case .Left, .Leading, .LeftMargin, .LeadingMargin, .Right, .Trailing, .RightMargin, .TrailingMargin, .CenterX, .CenterXWithinMargins, .Width:
+            return "h_"
+        case .Top, .FirstBaseline, .TopMargin, .Bottom, .LastBaseline, .BottomMargin, .CenterY, .CenterYWithinMargins, .Height:
+            return "v_"
+        }
+    }
+
+}
+
+#else
+
+/**
+    Extends `ReferenceAttribute` to ease the creation of
+    an `Attribute` signature
+ */
+internal extension ReferenceAttribute {
+
+    /// Signature of a `ReferenceAttribute`. Two possible values
+    /// depending on the Axis the `ReferenceAttribute` applies
+    var signatureString: String {
+        switch self {
+        case .Left, .Leading, .Right, .Trailing, .CenterX, .Width:
+            return "h_"
+        case .Top, .FirstBaseline, .Bottom, .LastBaseline, .CenterY, .Height:
+            return "v_"
+        }
+    }
+
+}
+
+#endif