diff --git a/basis/regexp/ast/ast.factor b/basis/regexp/ast/ast.factor
index be657227e5..2916ef7c32 100644
--- a/basis/regexp/ast/ast.factor
+++ b/basis/regexp/ast/ast.factor
@@ -21,12 +21,12 @@ CONSTANT: epsilon T{ tagged-epsilon { tag t } }
 TUPLE: concatenation first second ;
 
 : <concatenation> ( seq -- concatenation )
-    [ epsilon ] [ unclip [ concatenation boa ] reduce ] if-empty ;
+    [ epsilon ] [ [ ] [ concatenation boa ] map-reduce ] if-empty ;
 
 TUPLE: alternation first second ;
 
 : <alternation> ( seq -- alternation )
-    unclip [ alternation boa ] reduce ;
+    [ ] [ alternation boa ] map-reduce ;
 
 TUPLE: star term ;
 C: <star> star
diff --git a/basis/regexp/transition-tables/transition-tables.factor b/basis/regexp/transition-tables/transition-tables.factor
index 3c33ae8846..f452e3d24a 100644
--- a/basis/regexp/transition-tables/transition-tables.factor
+++ b/basis/regexp/transition-tables/transition-tables.factor
@@ -11,12 +11,7 @@ TUPLE: transition-table transitions start-state final-states ;
         H{ } clone >>transitions
         H{ } clone >>final-states ;
 
-: maybe-initialize-key ( key hashtable -- )
-    ! Why do we have to do this?
-    2dup key? [ 2drop ] [ [ H{ } clone ] 2dip set-at ] if ;
-
 :: (set-transition) ( from to obj hash -- )
-    to condition? [ to hash maybe-initialize-key ] unless
     from hash at
     [ [ to obj ] dip set-at ]
     [ to obj associate from hash set-at ] if* ;
@@ -25,7 +20,6 @@ TUPLE: transition-table transitions start-state final-states ;
     transitions>> (set-transition) ;
 
 :: (add-transition) ( from to obj hash -- )
-    to hash maybe-initialize-key
     from hash at
     [ [ to obj ] dip push-at ]
     [ to 1vector obj associate from hash set-at ] if* ;