Add method getting constraint with closure to ConstraintMakerRelatable (#663)

* add ConstraintMakerRelatable extension

* fix fatalError message

Co-authored-by: Jimi <jimi-hpcnt@hpcnt.com>

SnapKit.xcodeproj/project.pbxproj

@@ -8,6 +8,7 @@
 
 /* Begin PBXBuildFile section */
 		2DBA080E1F1FAD66001CFED4 /* Typealiases.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2DBA080D1F1FAD66001CFED4 /* Typealiases.swift */; };
+		3CA7D6C224592D4D005E10C2 /* ConstraintMakerRelatable+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3CA7D6C124592D4D005E10C2 /* ConstraintMakerRelatable+Extensions.swift */; };
 		7E1CB2AE227BB5520066B6C0 /* ConstraintDirectionalInsetTarget.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7E1CB2AD227BB5520066B6C0 /* ConstraintDirectionalInsetTarget.swift */; };
 		7E1CB2B0227BBDF70066B6C0 /* ConstraintDirectionalInsets.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7E1CB2AF227BBDF70066B6C0 /* ConstraintDirectionalInsets.swift */; };
 		EE235F5F1C5785BC00C08960 /* Debugging.swift in Sources */ = {isa = PBXBuildFile; fileRef = EE235F5E1C5785BC00C08960 /* Debugging.swift */; };
@@ -50,6 +51,7 @@
 
 /* Begin PBXFileReference section */
 		2DBA080D1F1FAD66001CFED4 /* Typealiases.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Typealiases.swift; sourceTree = "<group>"; };
+		3CA7D6C124592D4D005E10C2 /* ConstraintMakerRelatable+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "ConstraintMakerRelatable+Extensions.swift"; sourceTree = "<group>"; };
 		537DCE9A1C35CD4100B5B899 /* UIKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UIKit.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS9.1.sdk/System/Library/Frameworks/UIKit.framework; sourceTree = DEVELOPER_DIR; };
 		7E1CB2AD227BB5520066B6C0 /* ConstraintDirectionalInsetTarget.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConstraintDirectionalInsetTarget.swift; sourceTree = "<group>"; };
 		7E1CB2AF227BBDF70066B6C0 /* ConstraintDirectionalInsets.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConstraintDirectionalInsets.swift; sourceTree = "<group>"; };
@@ -139,6 +141,7 @@
 				EE235FC61C5785E200C08960 /* ConstraintView+Extensions.swift */,
 				EEF68FAF1D784FB100980C26 /* ConstraintLayoutGuide+Extensions.swift */,
 				EEF68FB31D784FBA00980C26 /* UILayoutSupport+Extensions.swift */,
+				3CA7D6C124592D4D005E10C2 /* ConstraintMakerRelatable+Extensions.swift */,
 			);
 			name = Extensions;
 			sourceTree = "<group>";
@@ -399,6 +402,7 @@
 				EE235FC01C5785DC00C08960 /* ConstraintViewDSL.swift in Sources */,
 				EE235F5F1C5785BC00C08960 /* Debugging.swift in Sources */,
 				EE235FC31C5785DC00C08960 /* ConstraintLayoutSupportDSL.swift in Sources */,
+				3CA7D6C224592D4D005E10C2 /* ConstraintMakerRelatable+Extensions.swift in Sources */,
 				EE235F7F1C5785C600C08960 /* ConstraintRelation.swift in Sources */,
 				EEF68FB41D784FBA00980C26 /* UILayoutSupport+Extensions.swift in Sources */,
 				EE235F701C5785C600C08960 /* ConstraintDescription.swift in Sources */,

Source/ConstraintMakerRelatable+Extensions.swift

@@ -0,0 +1,57 @@
+//
+//  SnapKit
+//
+//  Copyright (c) 2011-Present SnapKit Team - https://github.com/SnapKit
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if os(iOS) || os(tvOS)
+    import UIKit
+#else
+    import AppKit
+#endif
+
+
+extension ConstraintMakerRelatable {
+  
+    @discardableResult
+    public func equalToSuperview<T: ConstraintRelatableTarget>(_ closure: (ConstraintView) -> T, _ file: String = #file, line: UInt = #line) -> ConstraintMakerEditable {
+        guard let other = self.description.item.superview else {
+            fatalError("Expected superview but found nil when attempting make constraint `equalToSuperview`.")
+        }
+        return self.relatedTo(closure(other), relation: .equal, file: file, line: line)
+    }
+  
+    @discardableResult
+    public func lessThanOrEqualToSuperview<T: ConstraintRelatableTarget>(_ closure: (ConstraintView) -> T, _ file: String = #file, line: UInt = #line) -> ConstraintMakerEditable {
+        guard let other = self.description.item.superview else {
+            fatalError("Expected superview but found nil when attempting make constraint `lessThanOrEqualToSuperview`.")
+        }
+        return self.relatedTo(closure(other), relation: .lessThanOrEqual, file: file, line: line)
+    }
+  
+    @discardableResult
+    public func greaterThanOrEqualTo<T: ConstraintRelatableTarget>(_ closure: (ConstraintView) -> T, _ file: String = #file, line: UInt = #line) -> ConstraintMakerEditable {
+        guard let other = self.description.item.superview else {
+            fatalError("Expected superview but found nil when attempting make constraint `greaterThanOrEqualToSuperview`.")
+        }
+        return self.relatedTo(closure(other), relation: .greaterThanOrEqual, file: file, line: line)
+    }
+  
+}