tasks a-s

Task/Self-referential-sequence/Bracmat/self-referential-sequence.bracmat

@@ -0,0 +1,72 @@
+( ( self-referential
+  =   seq N next
+    .   ( next
+        =   R S d f
+          .   0:?S
+            &   whl
+              ' (@(!arg:%@?d ?arg)&(.!d)+!S:?S)
+            & :?R
+            &   whl
+              ' ( !S:#?f*(.?d)+?S
+                & !f !d !R:?R
+                )
+            & str$!R
+        )
+      & 1:?N
+      & !arg:?seq
+      &   whl
+        ' ( next$!arg:?arg
+          & ~(!seq:? !arg ?)
+          & !arg !seq:?seq
+          & 1+!N:?N
+          )
+      & (!seq.!N)
+  )
+& ( Perm
+  =   permutations S p
+    .   :?permutations
+      & ( perm
+        =   prefix List original A Z p
+          .     !arg:(?prefix.)
+              & str$!prefix:?p
+              & (!S:?+(.!p)+?|(.!p)+!S:?S)
+            | !arg:(0 ?.?)&
+            |   !arg:(?prefix.?List:?original)
+              &   whl
+                ' ( @(!List:%?A ?Z)
+                  & perm$(!prefix !A.!Z)
+                  & str$(!Z !A):~!original:?List
+                  )
+        )
+      & 0:?S
+      & perm$(.!arg)
+      & :?permutations
+      &   whl
+        ' ( !S:?*(.?p)+?S
+          & !p !permutations:?permutations
+          )
+      & !permutations
+  )
+& -1:?i:?max
+& :?seqs
+&   whl
+  ' ( 1+!i:<1000000:?i
+    & ( @(!i:? %@?a >%@!a ?)
+      |   self-referential$!i
+        : ( ?seq
+          .   ( >!max:?max&:?seqs
+              | !max
+              )
+            &     ( "Seed Value(s):" Perm$!i
+                  .   "Sequence: (same for all three seeds except for first element)
+"
+                      !seq
+                  )
+                  !seqs
+              : ?seqs
+          )
+      |
+      )
+    )
+& out$("Iterations:" !max !seqs)
+);