From a25856a9196939a839c395a609a16742ce7cb6ed Mon Sep 17 00:00:00 2001
From: Declan <5962877+dec1@users.noreply.github.com>
Date: Thu, 15 Jul 2021 20:17:01 +0200
Subject: [PATCH 1/4] extend OrderedSet with convenience methods
 ensure_at_front/end, useful eg in implementing a list of "recent documents"

---
 Ordered Set/OrderedSet.swift | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/Ordered Set/OrderedSet.swift b/Ordered Set/OrderedSet.swift
index 8b6df7d3e..275d9278f 100644
--- a/Ordered Set/OrderedSet.swift	
+++ b/Ordered Set/OrderedSet.swift	
@@ -73,5 +73,38 @@ public class OrderedSet<T: Hashable> {
   public func all() -> [T] {
     return objects
   }
+
+  // convenience checker - minimize need for client's knowledge of internals
+  public func contains(_ object: T) ->Bool {
+      return indexOfKey[object] != nil
+  }
+  
+  // O(1)
+  // append object (removing any existing other occurence)
+  public func ensure_at_end(_ object: T) {
+      if contains(object) {
+          remove(object)
+      }
+      add(object)
+  }
+  
+  // O(n)
+  // prepend object (removing any existing other occurence)
+  public func ensure_at_front(_ object: T) {
+      if contains(object) {
+          remove(object)      // could make this more efficient (at the expense of maintenance complexity) by not delegating to remove() and insert()
+                              // but instead doing manually, and running for loop just once at end
+      }
+      insert(object, at:0)
+      
+  }
+  
+  func debug_str() -> String  // useful for printing/debugging
+  {
+      var str = "OrderedSet: \n"
+      str += objects.map{"\($0)"}.joined(separator: ",")
+      
+      return str
+  }
 }
 

From de96a060c664b92cb7780bfdddfbedc552c707d2 Mon Sep 17 00:00:00 2001
From: Declan <5962877+dec1@users.noreply.github.com>
Date: Thu, 15 Jul 2021 20:26:16 +0200
Subject: [PATCH 2/4] fix typo

---
 Ordered Set/OrderedSet.swift | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Ordered Set/OrderedSet.swift b/Ordered Set/OrderedSet.swift
index 275d9278f..65483f8a2 100644
--- a/Ordered Set/OrderedSet.swift	
+++ b/Ordered Set/OrderedSet.swift	
@@ -80,7 +80,7 @@ public class OrderedSet<T: Hashable> {
   }
   
   // O(1)
-  // append object (removing any existing other occurence)
+  // append object (removing any existing other occurrence)
   public func ensure_at_end(_ object: T) {
       if contains(object) {
           remove(object)
@@ -89,7 +89,7 @@ public class OrderedSet<T: Hashable> {
   }
   
   // O(n)
-  // prepend object (removing any existing other occurence)
+  // prepend object (removing any existing other occurrence)
   public func ensure_at_front(_ object: T) {
       if contains(object) {
           remove(object)      // could make this more efficient (at the expense of maintenance complexity) by not delegating to remove() and insert()

From 6cdbfedf03596408203c23bb375ac726deb2d504 Mon Sep 17 00:00:00 2001
From: Declan <5962877+dec1@users.noreply.github.com>
Date: Thu, 15 Jul 2021 20:28:38 +0200
Subject: [PATCH 3/4] maintain consistent formatting

---
 Ordered Set/OrderedSet.swift | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/Ordered Set/OrderedSet.swift b/Ordered Set/OrderedSet.swift
index 65483f8a2..69fb56efd 100644
--- a/Ordered Set/OrderedSet.swift	
+++ b/Ordered Set/OrderedSet.swift	
@@ -96,14 +96,12 @@ public class OrderedSet<T: Hashable> {
                               // but instead doing manually, and running for loop just once at end
       }
       insert(object, at:0)
-      
   }
   
-  func debug_str() -> String  // useful for printing/debugging
-  {
+  // string representation, useful for printing/debugging
+  public func debug_str() -> String  {
       var str = "OrderedSet: \n"
       str += objects.map{"\($0)"}.joined(separator: ",")
-      
       return str
   }
 }

From aae2e071b0d0e6c87939502eede528e663532ffa Mon Sep 17 00:00:00 2001
From: Declan <5962877+dec1@users.noreply.github.com>
Date: Fri, 16 Jul 2021 08:58:36 +0200
Subject: [PATCH 4/4] bugfix: inserting at index 0 in empty container fails

---
 Ordered Set/OrderedSet.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Ordered Set/OrderedSet.swift b/Ordered Set/OrderedSet.swift
index 69fb56efd..850050098 100644
--- a/Ordered Set/OrderedSet.swift	
+++ b/Ordered Set/OrderedSet.swift	
@@ -16,7 +16,7 @@ public class OrderedSet<T: Hashable> {
   
   // O(n)
   public func insert(_ object: T, at index: Int) {
-    assert(index < objects.count, "Index should be smaller than object count")
+    assert(index <= objects.count, "Index should be smaller than object count")
     assert(index >= 0, "Index should be bigger than 0")
     
     guard indexOfKey[object] == nil else {