2013-08-16: added some unicode math fun.

added some unicode math fun.

diff --git a/d6.w b/d6.w
--- a/d6.w
+++ b/d6.w
@@ -17,6 +17,34 @@ define : check skill target effect-thres
                 . #t
             . #f
 
+define : Σ . n
+    apply + n
+
+define : ∪ . lists
+    apply append lists
+
+define : ∩ list1 list2
+    let : : h : make-hash-table
+        let fill : : toadd list2
+            when : not : equal? toadd '()
+                hash-set! h (list-ref toadd 0) #t
+                fill : list-tail toadd 1
+        let loop : (inboth '()) (tocheck list1)
+            if : equal? tocheck '()
+                . inboth
+                let : : cur : list-ref tocheck 0
+                    if : member cur list2
+                        loop 
+                            append inboth : list cur
+                            list-tail tocheck 1
+                        loop inboth : list-tail tocheck 1
+
+display : Σ 1 2 8 0  5 7 59 12 5
+newline
+display : ∪ '(1 2 3) '(4 5 6)
+newline
+display : ∩ '(1 789 7 897 89 78 78 97 89 2 3 6) '(4 5 6 2  8 7 879 879 879 879 8797 97 97 987 89789 7 7897 987 897 987 87 897 896)
+newline
 display : check 12 9 3
 newline
 display : roll