Added MultipleDeck which can be used in place of the old QuadDeck, converted cards from classes to records as it is useful to have default equality checks.

src/Nadeko.Econ/Deck/Regular/MultipleRegularDeck/MultipleRegularDeck.cs

@@ -0,0 +1,28 @@
+namespace Nadeko.Econ;
+
+public class MultipleRegularDeck : NewDeck<RegularCard, RegularSuit, RegularValue>
+{
+    private int Decks { get; }
+
+    public override int TotalCount { get; }
+
+    public MultipleRegularDeck(int decks = 1)
+    {
+        if (decks < 1)
+            throw new ArgumentOutOfRangeException(nameof(decks), "Has to be more than 0");
+
+        Decks = decks;
+        TotalCount = base.TotalCount * decks;
+        
+        for (var i = 0; i < Decks; i++)
+        {
+            foreach (var suit in _suits)
+            {
+                foreach (var val in _values)
+                {
+                    _cards.AddLast((RegularCard)Activator.CreateInstance(typeof(RegularCard), suit, val)!);
+                }
+            }
+        }
+    }
+}

src/Nadeko.Econ/Deck/Regular/RegularCard.cs

@@ -1,20 +1,4 @@
 namespace Nadeko.Econ;
 
-public sealed class RegularCard : NewCard<RegularSuit, RegularValue>
-{
-    public RegularCard(RegularSuit suit, RegularValue value) : base(suit, value)
-    {
-    }
-
-    private bool Equals(RegularCard other)
-        => other.Suit == this.Suit && other.Value == this.Value;
-
-    public override bool Equals(object? obj)
-        => ReferenceEquals(this, obj) || obj is RegularCard other && Equals(other);
-
-    public override int GetHashCode()
-        => Suit.GetHashCode() * 17 + Value.GetHashCode();
-
-    public override string ToString()
-        => $"{Value.ToString()}-{Suit.ToString()}";
-}
+public sealed record class RegularCard(RegularSuit Suit, RegularValue Value) 
+    : NewCard<RegularSuit, RegularValue>(Suit, Value);

src/Nadeko.Econ/Deck/Regular/RegularDeck.cs

@@ -2,4 +2,14 @@
 
 public sealed class RegularDeck : NewDeck<RegularCard, RegularSuit, RegularValue>
 {
+    public RegularDeck()
+    {
+        foreach (var suit in _suits)
+        {
+            foreach (var val in _values)
+            {
+                _cards.AddLast((RegularCard)Activator.CreateInstance(typeof(RegularCard), suit, val)!);
+            }
+        }
+    }
 }