1 files changed, 31 insertions, 0 deletions
diff --git a/ipl/packs/idol/sequence.iol b/ipl/packs/idol/sequence.iol
new file mode 100644
index 0000000..87bc2b7
--- /dev/null
+++ b/ipl/packs/idol/sequence.iol
@@ -0,0 +1,31 @@
+procedure sequence(bounds[ ])
+  return Sequence(bounds)
+end
+
+class Sequence(bounds,indices)
+  method max(i)
+    elem := self.bounds[i]
+    return (type(elem)== "integer",elem) | *elem-1
+  end
+  method elem(i)
+    elem := self.bounds[i]
+    return (type(elem)== "integer",self.indices[i]) | elem[self.indices[i]+1]
+  end
+  method activate()
+    top := *(self.indices)
+    if self.indices[1] > self$max(1) then fail
+    s := ""
+    every i := 1 to top do {
+      s ||:= self$elem(i)
+    }
+    repeat {
+       self.indices[top] +:= 1
+       if top=1 | (self.indices[top] <= self$max(top)) then break
+       self.indices[top] := 0
+       top -:= 1
+    }
+    return s
+  end
+initially
+  / (self.indices) := list(*self.bounds,0)
+end