Add a package for modelling cards

Time to do the fun non-yakshaving part.  I'll start out by writing
some custom types for the objects of concern: ranks, suits, cards and
sets of cards.

cantedraw.asd

@@ -2,6 +2,7 @@
   :components ((:file "packages")
                (:file "lib.macros")
                (:file "lib.functions")
+               (:file "model")
                (:file "main"))
   :build-operation "program-op"
   :build-pathname "bin/cantedraw"

model.lisp

@@ -0,0 +1,37 @@
+;;; model.lisp - 2025-02-14
+
+;; Copyright (C) 2025 Aryadev Chavali
+
+;; This program is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+;; FOR A PARTICULAR PURPOSE.  See the GNU General Public License Version 2 for
+;; details.
+
+;; You may distribute and modify this code under the terms of the GNU General
+;; Public License Version 2, which you should have received a copy of along with
+;; this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Model of cards and sets of cards in Lisp.
+
+;;; Code:
+
+(in-package :cantedraw.model)
+
+(deftype rank ()
+  `(or (member :Jack :Queen :King :Ace)
+       (integer 2 10)))
+
+(deftype suit ()
+  `(member :Diamonds :Clubs :Hearts :Spades :Joker))
+
+(deftype card () `(cons rank suit))
+
+(deftype int-card () `(integer 0 51))
+
+(fn cardsetp (lst) (-> (list) boolean)
+  (every #'(lambda (x) (typep x 'card)) lst))
+
+(deftype cardset () `(and list (satisfies cardsetp)))
+

packages.lisp

@@ -32,6 +32,10 @@
    :range :take :split
    :rev-map))
 
+(defpackage cantedraw.model
+  (:use :cl :cantedraw.lib.macros :cantedraw.lib.functions)
+  (:export :int-card :rank :suit :card :cardset))
+
 (defpackage cantedraw.main
   (:use :cl :cantedraw.lib.macros :cantedraw.lib.functions)
   (:export :start))