     0 pos set
     f lrstack set
     V{ } clone error-stack set
-    H{ } clone heads set
-    H{ } clone packrat set
+    H{ } clone \ heads set
+    H{ } clone \ packrat set
   ] H{ } make-assoc swap bind ; inline
 
 


:: setup-lr ( r l -- )
  l head>> [
    r V{ } clone V{ } clone <head> l (>>head)
  ] unless
  r l lrstack get (setup-lr) ;


:: recall ( r p -- memo-entry )
  [let* |
          m [ p r memo ]
          h [ p heads at ]
        |
    h [
      m r h involved-set>> h rule>> suffix member? not and [
        fail p memo-entry boa
      ] [
        r h eval-set>> member? [
          h [ r swap remove ] change-eval-set drop
